1
|
Almeida AJD, Hobson BA, Saito N, Bruun DA, Porter VA, Harvey DJ, Garbow JR, Chaudhari AJ, Lein PJ. Quantitative T 2 mapping-based longitudinal assessment of brain injury and therapeutic rescue in the rat following acute organophosphate intoxication. Neuropharmacology 2024; 249:109895. [PMID: 38437913 PMCID: PMC11227117 DOI: 10.1016/j.neuropharm.2024.109895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 02/07/2024] [Accepted: 02/29/2024] [Indexed: 03/06/2024]
Abstract
Acute intoxication with organophosphate (OP) cholinesterase inhibitors poses a significant public health risk. While currently approved medical countermeasures can improve survival rates, they often fail to prevent chronic neurological damage. Therefore, there is need to develop effective therapies and quantitative metrics for assessing OP-induced brain injury and its rescue by these therapies. In this study we used a rat model of acute intoxication with the OP, diisopropylfluorophosphate (DFP), to test the hypothesis that T2 measures obtained from brain magnetic resonance imaging (MRI) scans provide quantitative metrics of brain injury and therapeutic efficacy. Adult male Sprague Dawley rats were imaged on a 7T MRI scanner at 3, 7 and 28 days post-exposure to DFP or vehicle (VEH) with or without treatment with the standard of care antiseizure drug, midazolam (MDZ); a novel antiseizure medication, allopregnanolone (ALLO); or combination therapy with MDZ and ALLO (DUO). Our results show that mean T2 values in DFP-exposed animals were: (1) higher than VEH in all volumes of interest (VOIs) at day 3; (2) decreased with time; and (3) decreased in the thalamus at day 28. Treatment with ALLO or DUO, but not MDZ alone, significantly decreased mean T2 values relative to untreated DFP animals in the piriform cortex at day 3. On day 28, the DUO group showed the most favorable T2 characteristics. This study supports the utility of T2 mapping for longitudinally monitoring brain injury and highlights the therapeutic potential of ALLO as an adjunct therapy to mitigate chronic morbidity associated with acute OP intoxication.
Collapse
Affiliation(s)
- Alita Jesal D Almeida
- Department of Biomedical Engineering, University of California-Davis College of Engineering, Davis, CA, 95616, USA; Department of Radiology, University of California-Davis School of Medicine, Sacramento, CA, 95817, USA.
| | - Brad A Hobson
- Center for Molecular and Genomic Imaging, Department of Biomedical Engineering, University of California-Davis College of Engineering, Davis, CA, 95616, USA.
| | - Naomi Saito
- Department of Public Health Sciences, University of California-Davis School of Medicine, Davis, CA, 95616, USA
| | - Donald A Bruun
- Department of Molecular Biosciences, University of California-Davis School of Veterinary Medicine, Davis, CA, 95616, USA.
| | - Valerie A Porter
- Department of Biomedical Engineering, University of California-Davis College of Engineering, Davis, CA, 95616, USA; Department of Radiology, University of California-Davis School of Medicine, Sacramento, CA, 95817, USA.
| | - Danielle J Harvey
- Department of Public Health Sciences, University of California-Davis School of Medicine, Davis, CA, 95616, USA.
| | - Joel R Garbow
- Department of Radiology, Washington University School of Medicine, St Louis, MO, 63110, USA.
| | - Abhijit J Chaudhari
- Department of Radiology, University of California-Davis School of Medicine, Sacramento, CA, 95817, USA; Center for Molecular and Genomic Imaging, Department of Biomedical Engineering, University of California-Davis College of Engineering, Davis, CA, 95616, USA.
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California-Davis School of Veterinary Medicine, Davis, CA, 95616, USA.
| |
Collapse
|
2
|
Tsai YH, González EA, Grodzki ACG, Bruun DA, Saito NH, Harvey DJ, Lein PJ. Acute intoxication with diisopropylfluorophosphate promotes cellular senescence in the adult male rat brain. FRONTIERS IN TOXICOLOGY 2024; 6:1360359. [PMID: 38745692 PMCID: PMC11091247 DOI: 10.3389/ftox.2024.1360359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 04/12/2024] [Indexed: 05/16/2024] Open
Abstract
Acute intoxication with high levels of organophosphate (OP) cholinesterase inhibitors can cause cholinergic crisis, which is associated with acute, life-threatening parasympathomimetic symptoms, respiratory depression and seizures that can rapidly progress to status epilepticus (SE). Clinical and experimental data demonstrate that individuals who survive these acute neurotoxic effects often develop significant chronic morbidity, including behavioral deficits. The pathogenic mechanism(s) that link acute OP intoxication to chronic neurological deficits remain speculative. Cellular senescence has been linked to behavioral deficits associated with aging and neurodegenerative disease, but whether acute OP intoxication triggers cellular senescence in the brain has not been investigated. Here, we test this hypothesis in a rat model of acute intoxication with the OP diisopropylfluorophosphate (DFP). Adult male Sprague-Dawley rats were administered DFP (4 mg/kg, s.c.). Control animals were administered an equal volume (300 µL) of sterile phosphate-buffered saline (s.c.). Both groups were subsequently injected with atropine sulfate (2 mg/kg, i.m.) and 2-pralidoxime (25 mg/kg, i.m.). DFP triggered seizure activity within minutes that rapidly progressed to SE, as determined using behavioral seizure criteria. Brains were collected from animals at 1, 3, and 6 months post-exposure for immunohistochemical analyses of p16, a biomarker of cellular senescence. While there was no immunohistochemical evidence of cellular senescence at 1-month post-exposure, at 3- and 6-months post-exposure, p16 immunoreactivity was significantly increased in the CA3 and dentate gyrus of the hippocampus, amygdala, piriform cortex and thalamus, but not the CA1 region of the hippocampus or the somatosensory cortex. Co-localization of p16 immunoreactivity with cell-specific biomarkers, specifically, NeuN, GFAP, S100β, IBA1 and CD31, revealed that p16 expression in the brain of DFP animals is neuron-specific. The spatial distribution of p16-immunopositive cells overlapped with expression of senescence associated β-galactosidase and with degenerating neurons identified by FluoroJade-C (FJC) staining. The co-occurrence of p16 and FJC was positively correlated. This study implicates cellular senescence as a novel pathogenic mechanism underlying the chronic neurological deficits observed in individuals who survive OP-induced cholinergic crisis.
Collapse
Affiliation(s)
- Yi-Hua Tsai
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Eduardo A. González
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Ana C. G. Grodzki
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Donald A. Bruun
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Naomi H. Saito
- Department of Public Health Sciences, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Danielle J. Harvey
- Department of Public Health Sciences, School of Medicine, University of California, Davis, Davis, CA, United States
| | - Pamela J. Lein
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| |
Collapse
|
3
|
Andrew PM, Feng W, Calsbeek JJ, Antrobus SP, Cherednychenko GA, MacMahon JA, Bernardino PN, Liu X, Harvey DJ, Lein PJ, Pessah IN. The α4 Nicotinic Acetylcholine Receptor Is Necessary for the Initiation of Organophosphate-Induced Neuronal Hyperexcitability. TOXICS 2024; 12:263. [PMID: 38668486 PMCID: PMC11054284 DOI: 10.3390/toxics12040263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 03/20/2024] [Accepted: 03/27/2024] [Indexed: 04/29/2024]
Abstract
Acute intoxication with organophosphorus (OP) cholinesterase inhibitors can produce seizures that rapidly progress to life-threatening status epilepticus. Significant research effort has been focused on investigating the involvement of muscarinic acetylcholine receptors (mAChRs) in OP-induced seizure activity. In contrast, there has been far less attention on nicotinic AChRs (nAChRs) in this context. Here, we address this data gap using a combination of in vitro and in vivo models. Pharmacological antagonism and genetic deletion of α4, but not α7, nAChR subunits prevented or significantly attenuated OP-induced electrical spike activity in acute hippocampal slices and seizure activity in mice, indicating that α4 nAChR activation is necessary for neuronal hyperexcitability triggered by acute OP exposures. These findings not only suggest that therapeutic strategies for inhibiting the α4 nAChR subunit warrant further investigation as prophylactic and immediate treatments for acute OP-induced seizures, but also provide mechanistic insight into the role of the nicotinic cholinergic system in seizure generation.
Collapse
Affiliation(s)
- Peter M. Andrew
- Department of Molecular Biosciences, UC Davis School of Veterinary Medicine, Davis, CA 95616, USA; (P.M.A.); (W.F.); (J.J.C.); (S.P.A.); (G.A.C.); (J.A.M.); (P.N.B.); (X.L.)
| | - Wei Feng
- Department of Molecular Biosciences, UC Davis School of Veterinary Medicine, Davis, CA 95616, USA; (P.M.A.); (W.F.); (J.J.C.); (S.P.A.); (G.A.C.); (J.A.M.); (P.N.B.); (X.L.)
| | - Jonas J. Calsbeek
- Department of Molecular Biosciences, UC Davis School of Veterinary Medicine, Davis, CA 95616, USA; (P.M.A.); (W.F.); (J.J.C.); (S.P.A.); (G.A.C.); (J.A.M.); (P.N.B.); (X.L.)
| | - Shane P. Antrobus
- Department of Molecular Biosciences, UC Davis School of Veterinary Medicine, Davis, CA 95616, USA; (P.M.A.); (W.F.); (J.J.C.); (S.P.A.); (G.A.C.); (J.A.M.); (P.N.B.); (X.L.)
| | - Gennady A. Cherednychenko
- Department of Molecular Biosciences, UC Davis School of Veterinary Medicine, Davis, CA 95616, USA; (P.M.A.); (W.F.); (J.J.C.); (S.P.A.); (G.A.C.); (J.A.M.); (P.N.B.); (X.L.)
| | - Jeremy A. MacMahon
- Department of Molecular Biosciences, UC Davis School of Veterinary Medicine, Davis, CA 95616, USA; (P.M.A.); (W.F.); (J.J.C.); (S.P.A.); (G.A.C.); (J.A.M.); (P.N.B.); (X.L.)
| | - Pedro N. Bernardino
- Department of Molecular Biosciences, UC Davis School of Veterinary Medicine, Davis, CA 95616, USA; (P.M.A.); (W.F.); (J.J.C.); (S.P.A.); (G.A.C.); (J.A.M.); (P.N.B.); (X.L.)
| | - Xiuzhen Liu
- Department of Molecular Biosciences, UC Davis School of Veterinary Medicine, Davis, CA 95616, USA; (P.M.A.); (W.F.); (J.J.C.); (S.P.A.); (G.A.C.); (J.A.M.); (P.N.B.); (X.L.)
| | - Danielle J. Harvey
- Department of Public Health Sciences, UC Davis School of Medicine, Davis, CA 95616, USA;
| | - Pamela J. Lein
- Department of Molecular Biosciences, UC Davis School of Veterinary Medicine, Davis, CA 95616, USA; (P.M.A.); (W.F.); (J.J.C.); (S.P.A.); (G.A.C.); (J.A.M.); (P.N.B.); (X.L.)
| | - Isaac N. Pessah
- Department of Molecular Biosciences, UC Davis School of Veterinary Medicine, Davis, CA 95616, USA; (P.M.A.); (W.F.); (J.J.C.); (S.P.A.); (G.A.C.); (J.A.M.); (P.N.B.); (X.L.)
| |
Collapse
|
4
|
Kolić D, Kovarik Z. N-methyl-d-aspartate receptors: Structure, function, and role in organophosphorus compound poisoning. Biofactors 2024. [PMID: 38415801 DOI: 10.1002/biof.2048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 02/05/2024] [Indexed: 02/29/2024]
Abstract
Acute organophosphorus compound (OP) poisoning induces symptoms of the cholinergic crises with the occurrence of severe epileptic seizures. Seizures are induced by hyperstimulation of the cholinergic system, but are enhanced by hyperactivation of the glutamatergic system. Overstimulation of muscarinic cholinergic receptors by the elevated acetylcholine causes glutamatergic hyperexcitation and an increased influx of Ca2+ into neurons through a type of ionotropic glutamate receptors, N-methyl-d-aspartate (NMDA) receptors (NMDAR). These excitotoxic signaling processes generate reactive oxygen species, oxidative stress, and activation of the neuroinflammatory response, which can lead to recurrent epileptic seizures, neuronal cell death, and long-term neurological damage. In this review, we illustrate the NMDAR structure, complexity of subunit composition, and the various receptor properties that change accordingly. Although NMDARs are in normal physiological conditions important for controlling synaptic plasticity and mediating learning and memory functions, we elaborate the detrimental role NMDARs play in neurotoxicity of OPs and focus on the central role NMDAR inhibition plays in suppressing neurotoxicity and modulating the inflammatory response. The limited efficacy of current medical therapies for OP poisoning concerning the development of pharmacoresistance and mitigating proinflammatory response highlights the importance of NMDAR inhibitors in preventing neurotoxic processes and points to new avenues for exploring therapeutics for OP poisoning.
Collapse
Affiliation(s)
- Dora Kolić
- Division of Toxicology, Institute for Medical Research and Occupational Health, Zagreb, Croatia
| | - Zrinka Kovarik
- Division of Toxicology, Institute for Medical Research and Occupational Health, Zagreb, Croatia
- Department of Chemistry, Faculty of Science, University of Zagreb, Zagreb, Croatia
| |
Collapse
|
5
|
Liang LP, Pearson-Smith JN, Day BJ, Patel M. Novel Catalytic Antioxidant Formulation Decreases Oxidative Stress, Neuroinflammation and Cognitive Dysfunction in a Model of Nerve Agent Intoxication. J Pharmacol Exp Ther 2024; 388:358-366. [PMID: 37652711 PMCID: PMC10801718 DOI: 10.1124/jpet.123.001708] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 08/15/2023] [Accepted: 08/18/2023] [Indexed: 09/02/2023] Open
Abstract
Reactive oxygen species have an emerging role in the pathologic consequences of status epilepticus. We have previously demonstrated the efficacy of a water-for-injection formulation of the meso-porphyrin catalytic antioxidant, manganese (III) meso-tetrakis (N-N-diethylimidazole) porphyrin (AEOL10150) against oxidative stress, neuroinflammation, and neuronal death initiated by kainic acid, pilocarpine, diisopropylflurophosphate (DFP), and soman. This previous dose and dosing strategy of AEOL10150 required smaller multiple daily injections, precluding our ability to test its efficacy against delayed consequences of nerve agent exposure such as neurodegeneration and cognitive dysfunction. Therefore, we developed formulations of AEOL10150 designed to deliver a larger dose once daily with improved brain pharmacodynamics. We examined four new formulations of AEOL10150 that resulted in 8 times higher subcutaneous dose with lower acute toxicity, slower absorption, longer half-life, and higher maximal plasma concentrations compared with our previous strategy. AEOL10150 brain levels exhibited improved pharmacodynamics over 24 hours with all four formulations. We tested a subcutaneous dose of 40 mg/kg AEOL10150 in two formulations (2% carboxymethyl cellulose and 4% polyethylene glycol-4000) in the DFP rat model, and both formulations exhibited significant protection against DFP-induced oxidative stress. Additionally, and in one formulation (4% polyethylene glycol-4000), AEOL10150 significantly protected against DFP-induced neuronal death, microglial activation, delayed memory impairment, and mortality. These results suggest that reformulation of AEOL10150 can attenuate acute and delayed outcomes of organophosphate neurotoxicity. SIGNIFICANCE STATEMENT: Reformulation of manganese (III) meso-tetrakis (N-N-diethylimidazole) porphyrin allowed higher tolerated doses of the compound with improved pharmacodynamics. Specifically, one new formulation allowed fewer daily doses and improvement in acute and delayed outcomes of organophosphate toxicity.
Collapse
Affiliation(s)
- Li-Ping Liang
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, Colorado (L.-P.L., J.N.P.-S., B.J.D., M.P.); and Department of Medicine, National Jewish Health, Denver, Colorado (B.J.D.)
| | - Jennifer N Pearson-Smith
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, Colorado (L.-P.L., J.N.P.-S., B.J.D., M.P.); and Department of Medicine, National Jewish Health, Denver, Colorado (B.J.D.)
| | - Brian J Day
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, Colorado (L.-P.L., J.N.P.-S., B.J.D., M.P.); and Department of Medicine, National Jewish Health, Denver, Colorado (B.J.D.)
| | - Manisha Patel
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, Colorado (L.-P.L., J.N.P.-S., B.J.D., M.P.); and Department of Medicine, National Jewish Health, Denver, Colorado (B.J.D.)
| |
Collapse
|
6
|
Shulaeva MM, Zueva IV, Nikolaev AE, Saifina LF, Sharafutdinova DR, Babaev VM, Semenov VE, Petrov KA. Conjugates of nucleobases with triazole-hydroxamic acids for the reactivation of acetylcholinesterase and treatment of delayed neurodegeneration induced by organophosphate poisoning. Bioorg Chem 2023; 141:106858. [PMID: 37774432 DOI: 10.1016/j.bioorg.2023.106858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/26/2023] [Accepted: 09/09/2023] [Indexed: 10/01/2023]
Abstract
A series of new uncharged conjugates of adenine, 3,6-dimetyl-, 1,6-dimethyl- and 6-methyluracil with 1,2,4-triazole-3-hydroxamic and 1,2,3-triazole-4-hydroxamic acid moieties were synthesized and studied as reactivators of organophosphate-inhibited cholinesterase. It is shown that triazole-hydroxamic acids can reactivate acetylcholinesterase (AChE) inhibited by paraoxon (POX) in vitro, offering reactivation constants comparable to those of pralidoxime (2-PAM). However, in contrast to 2-PAM, triazole-hydroxamic acids demonstrated the ability to reactivate AChE in the brain of rats poisoned with POX. At a dose of 200 mg/kg (i.v.), the lead compound 3e reactivated 22.6 ± 7.3% of brain AChE in rats poisoned with POX. In a rat model of POX-induced delayed neurodegeneration, compound 3e reduced the neuronal injury labeled with FJB upon double administration 1 and 3 h after poisoning. Compound 3e was also shown to prevent memory impairment of POX-poisoned rats as tested in a Morris water maze.
Collapse
Affiliation(s)
- Marina M Shulaeva
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan 420088, Russian Federation
| | - Irina V Zueva
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan 420088, Russian Federation
| | - Anton E Nikolaev
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan 420088, Russian Federation
| | - Liliya F Saifina
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan 420088, Russian Federation
| | - Dilyara R Sharafutdinova
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan 420088, Russian Federation
| | - Vasily M Babaev
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan 420088, Russian Federation
| | - Vyacheslav E Semenov
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan 420088, Russian Federation.
| | - Konstantin A Petrov
- Arbuzov Institute of Organic and Physical Chemistry, Federal Research Center "Kazan Scientific Center of the Russian Academy of Sciences", Arbuzov str., 8, Kazan 420088, Russian Federation; Kazan Federal University, Kremlyovskaya str., 18, Kazan 420008, Russian Federation
| |
Collapse
|
7
|
Zou S, Wang Q, He Q, Liu G, Song J, Li J, Wang F, Huang Y, Hu Y, Zhou D, Lv Y, Zhu Y, Wang B, Zhang L. Brain-targeted nanoreactors prevent the development of organophosphate-induced delayed neurological damage. J Nanobiotechnology 2023; 21:256. [PMID: 37550745 PMCID: PMC10405429 DOI: 10.1186/s12951-023-02039-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Accepted: 07/31/2023] [Indexed: 08/09/2023] Open
Abstract
BACKGROUND Organophosphate (OP)-induced delayed neurological damage is attributed to permanent neuropathological lesions caused by irreversible OP-neurocyte interactions, without potent brain-targeted etiological antidotes to date. The development of alternative therapies to achieve intracerebral OP detoxification is urgently needed. METHODS We designed a brain-targeted nanoreactor by integrating enzyme immobilization and biomimetic membrane camouflaging protocols with careful characterization, and then examined its blood-brain barrier (BBB) permeability both in vitro and in vivo. Subsequently, the oxidative stress parameters, neuroinflammatory factors, apoptotic proteins and histopathological changes were measured and neurobehavioral tests were performed. RESULTS The well-characterized nanoreactors exerted favourable BBB penetration capability both in vitro and in vivo, significantly inhibiting OP-induced intracerebral damage. At the cellular and tissue levels, nanoreactors obviously blocked oxidative stress, cellular apoptosis, inflammatory reactions and brain histopathological damage. Furthermore, nanoreactors radically prevented the occurrence of OP-induced delayed cognitive deficits and psychiatric abnormality. CONCLUSION The nanoreactors significantly prevented the development of OP-induced delayed neurological damage, suggesting a potential brain-targeted etiological strategy to attenuate OP-related delayed neurological and neurobehavioral disorders.
Collapse
Affiliation(s)
- Shuaijun Zou
- Department of Marine Biomedicine and Polar Medicine, Naval Special Medical Centre, Naval Medical University, Shanghai, 200433, China
| | - Qianqian Wang
- Department of Marine Biomedicine and Polar Medicine, Naval Special Medical Centre, Naval Medical University, Shanghai, 200433, China
| | - Qian He
- The Third Affiliated Hospital, Naval Medical University, Shanghai, 200433, China
| | - Guoyan Liu
- Department of Marine Biomedicine and Polar Medicine, Naval Special Medical Centre, Naval Medical University, Shanghai, 200433, China
| | - Juxingsi Song
- Department of Marine Biomedicine and Polar Medicine, Naval Special Medical Centre, Naval Medical University, Shanghai, 200433, China
| | - Jie Li
- Department of Marine Biomedicine and Polar Medicine, Naval Special Medical Centre, Naval Medical University, Shanghai, 200433, China
| | - Fan Wang
- Department of Marine Biomedicine and Polar Medicine, Naval Special Medical Centre, Naval Medical University, Shanghai, 200433, China
| | - Yichao Huang
- Department of Marine Biomedicine and Polar Medicine, Naval Special Medical Centre, Naval Medical University, Shanghai, 200433, China
| | - Yanan Hu
- Department of Marine Biomedicine and Polar Medicine, Naval Special Medical Centre, Naval Medical University, Shanghai, 200433, China
| | - Dayuan Zhou
- Department of Marine Biomedicine and Polar Medicine, Naval Special Medical Centre, Naval Medical University, Shanghai, 200433, China
| | - Yongfei Lv
- Department of Marine Biomedicine and Polar Medicine, Naval Special Medical Centre, Naval Medical University, Shanghai, 200433, China
| | - Yuanjie Zhu
- Department of Marine Biological Injury and Dermatology, Naval Special Medical Centre, Naval Medical University, Shanghai, 200052, China.
| | - Beilei Wang
- Department of Marine Biomedicine and Polar Medicine, Naval Special Medical Centre, Naval Medical University, Shanghai, 200433, China.
| | - Liming Zhang
- Department of Marine Biomedicine and Polar Medicine, Naval Special Medical Centre, Naval Medical University, Shanghai, 200433, China.
| |
Collapse
|
8
|
Younis NS, Mohamed ME. Anethole Pretreatment Modulates Cerebral Ischemia/Reperfusion: The Role of JNK, p38, MMP-2 and MMP-9 Pathways. Pharmaceuticals (Basel) 2023; 16:ph16030442. [PMID: 36986541 PMCID: PMC10057436 DOI: 10.3390/ph16030442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Revised: 03/08/2023] [Accepted: 03/13/2023] [Indexed: 03/17/2023] Open
Abstract
Anethole (AN) is one of the major constituents of several plant oils, demonstrating plentiful pharmacological actions. Ischemic stroke is the main cause of morbidity and death worldwide, particularly since ischemic stroke therapeutic choices are inadequate and limited; thus, the development of new therapeutic options is indispensable. This study was planned to explore the preventive actions of AN in ameliorating cerebral ischemia/reperfusion-induced brain damage and BBB permeability leakage, as well as to explore anethole’s potential mechanisms of action. The proposed mechanisms included modulating JNK and p38 as well as MMP-2 and MMP-9 pathways. Sprague–Dawley male rats were randomly assigned into four groups: sham, middle cerebral artery occlusion (MCAO), AN125 + MCAO, and AN250 + MCAO. Animals in the third and fourth groups were pretreated with AN 125 or 250 mg/kg orally, respectively, for two weeks before performing middle cerebral artery occlusion (MCAO)-induced cerebral ischemic/reperfusion surgery. Animals that experienced cerebral ischemia/reperfusion exhibited amplified infarct volume, Evans blue intensity, brain water content, Fluoro-Jade B-positive cells, severe neurological deficits, and numerous histopathological alterations. MCAO animals exhibited elevated MMP-9 and MMP-2 gene expressions, enzyme activities, augmented JNK, and p38 phosphorylation. On the other hand, pretreatment with AN diminished the infarct volume, Evans blue dye intensity, brain water content, and Fluoro-Jade B-positive cells, improved the neurological score and enhanced histopathological examination. AN effectively lowered MMP-9 and MMP-2 gene expression and enzyme activities and diminished phosphorylated JNK, p38. AN decreased MDA content, amplified GSH/GSSG ratio, SOD, and CAT, decreased the serum and brain tissue homogenate inflammatory cytokines (TNF-α, IL-6, IL-1β), NF-κB, and deterred the apoptotic status. This study revealed the neuroprotective ability of AN against cerebral ischemia/reperfusion in rats. AN boosted blood–brain barrier integrity via modulating MMPs and diminished oxidative stress, inflammation, and apoptosis through the JNK/p38 pathway.
Collapse
Affiliation(s)
- Nancy S. Younis
- Department of Pharmaceutical Sciences, College of Clinical Pharmacy, King Faisal University, Al-Ahsa 31982, Saudi Arabia
- Zagazig University Hospitals, Zagazig University, Zagazig 44519, Egypt
- Correspondence:
| | - Maged E. Mohamed
- Department of Pharmaceutical Sciences, College of Clinical Pharmacy, King Faisal University, Al-Ahsa 31982, Saudi Arabia
- Department of Pharmacognosy, College of Pharmacy, Zagazig University, Zagazig 44519, Egypt
| |
Collapse
|
9
|
Ruíz-Arias MA, Medina-Díaz IM, Bernal-Hernández YY, Agraz-Cibrián JM, González-Arias CA, Barrón-Vivanco BS, Herrera-Moreno JF, Verdín-Betancourt FA, Zambrano-Zaragoza JF, Rojas-García AE. Hematological indices as indicators of inflammation induced by exposure to pesticides. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:19466-19476. [PMID: 36239889 PMCID: PMC9561311 DOI: 10.1007/s11356-022-23509-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 10/04/2022] [Indexed: 06/16/2023]
Abstract
Pesticide toxicity, both acute and chronic, is a global public health concern. Pesticides are involved in abnormal inflammatory responses by interfering with the normal physiology and metabolic status of cells. In this regard, inflammatory indices aggregate index of systemic inflammation (AISI), monocyte-to-high-density lipoprotein ratio, monocyte-to-lymphocyte ratio (MLR), neutrophil-to-lymphocyte platelet ratio (NLPR), neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, systemic immune inflammation index, and systemic inflammation response index (SIRI) have been used as predictive markers of inflammatory status in several diseases and also in acute poisoning events. This study aimed to determine systemic inflammation indices and their relationship with pesticide exposure from urban sprayers in 302 individuals categorized into three groups (reference group and moderate and high exposure groups). The data suggest that the AISI, MLR, NLPR, and SIRI indices were significantly higher in the exposed groups compared with the reference group. In conclusion, this study proposes that inflammation indices warrant further attention in order to assess their value as early biomarkers of acute and chronic pesticide intoxication.
Collapse
Affiliation(s)
- Miguel Alfonso Ruíz-Arias
- Laboratorio de Contaminación y Toxicología Ambiental, Secretaría de Investigación y Posgrado, Universidad Autónoma de Nayarit, Ciudad de La Cultura S/N. Col. Centro, Tepic, 63000, Nayarit, México
- Programa de Doctorado en Ciencias Biológico Agropecuarias. Área de Ciencias Ambientales. Universidad Autónoma de Nayarit, Km. 9 Carretera Tepic-Compostela, Xalisco, Nayarit, México
| | - Irma Martha Medina-Díaz
- Laboratorio de Contaminación y Toxicología Ambiental, Secretaría de Investigación y Posgrado, Universidad Autónoma de Nayarit, Ciudad de La Cultura S/N. Col. Centro, Tepic, 63000, Nayarit, México
| | - Yael Yvette Bernal-Hernández
- Laboratorio de Contaminación y Toxicología Ambiental, Secretaría de Investigación y Posgrado, Universidad Autónoma de Nayarit, Ciudad de La Cultura S/N. Col. Centro, Tepic, 63000, Nayarit, México
| | - Juan Manuel Agraz-Cibrián
- Unidad Académica de Ciencias Químico Biológicas y Farmacéuticas, Universidad Autónoma de Nayarit, Ciudad de La Cultura S/N. Col. Centro, Tepic, 63000, Nayarit, México
| | - Cyndia Azucena González-Arias
- Laboratorio de Contaminación y Toxicología Ambiental, Secretaría de Investigación y Posgrado, Universidad Autónoma de Nayarit, Ciudad de La Cultura S/N. Col. Centro, Tepic, 63000, Nayarit, México
| | - Briscia Socorro Barrón-Vivanco
- Laboratorio de Contaminación y Toxicología Ambiental, Secretaría de Investigación y Posgrado, Universidad Autónoma de Nayarit, Ciudad de La Cultura S/N. Col. Centro, Tepic, 63000, Nayarit, México
| | - José Francisco Herrera-Moreno
- Laboratorio de Contaminación y Toxicología Ambiental, Secretaría de Investigación y Posgrado, Universidad Autónoma de Nayarit, Ciudad de La Cultura S/N. Col. Centro, Tepic, 63000, Nayarit, México
| | - Francisco Alberto Verdín-Betancourt
- Laboratorio de Contaminación y Toxicología Ambiental, Secretaría de Investigación y Posgrado, Universidad Autónoma de Nayarit, Ciudad de La Cultura S/N. Col. Centro, Tepic, 63000, Nayarit, México
| | - José Francisco Zambrano-Zaragoza
- Unidad Académica de Ciencias Químico Biológicas y Farmacéuticas, Universidad Autónoma de Nayarit, Ciudad de La Cultura S/N. Col. Centro, Tepic, 63000, Nayarit, México
| | - Aurora Elizabeth Rojas-García
- Laboratorio de Contaminación y Toxicología Ambiental, Secretaría de Investigación y Posgrado, Universidad Autónoma de Nayarit, Ciudad de La Cultura S/N. Col. Centro, Tepic, 63000, Nayarit, México.
| |
Collapse
|
10
|
Somkhit J, Yanicostas C, Soussi-Yanicostas N. Microglia Remodelling and Neuroinflammation Parallel Neuronal Hyperactivation Following Acute Organophosphate Poisoning. Int J Mol Sci 2022; 23:ijms23158240. [PMID: 35897817 PMCID: PMC9332153 DOI: 10.3390/ijms23158240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Revised: 07/08/2022] [Accepted: 07/13/2022] [Indexed: 01/27/2023] Open
Abstract
Organophosphate (OP) compounds include highly toxic chemicals widely used both as pesticides and as warfare nerve agents. Existing countermeasures are lifesaving, but do not alleviate all long-term neurological sequelae, making OP poisoning a public health concern worldwide and the search for fully efficient antidotes an urgent need. OPs cause irreversible acetylcholinesterase (AChE) inhibition, inducing the so-called cholinergic syndrome characterized by peripheral manifestations and seizures associated with permanent psychomotor deficits. Besides immediate neurotoxicity, recent data have also identified neuroinflammation and microglia activation as two processes that likely play an important, albeit poorly understood, role in the physiopathology of OP intoxication and its long-term consequences. To gain insight into the response of microglia to OP poisoning, we used a previously described model of diisopropylfluorophosphate (DFP) intoxication of zebrafish larvae. This model reproduces almost all the defects seen in poisoned humans and preclinical models, including AChE inhibition, neuronal epileptiform hyperexcitation, and increased neuronal death. Here, we investigated in vivo the consequences of acute DFP exposure on microglia morphology and behaviour, and on the expression of a set of pro- and anti-inflammatory cytokines. We also used a genetic method of microglial ablation to evaluate the role in the OP-induced neuropathology. We first showed that DFP intoxication rapidly induced deep microglial phenotypic remodelling resembling that seen in M1-type activated macrophages and characterized by an amoeboid morphology, reduced branching, and increased mobility. DFP intoxication also caused massive expression of genes encoding pro-inflammatory cytokines Il1β, Tnfα, Il8, and to a lesser extent, immuno-modulatory cytokine Il4, suggesting complex microglial reprogramming that included neuroinflammatory activities. Finally, microglia-depleted larvae were instrumental in showing that microglia were major actors in DFP-induced neuroinflammation and, more importantly, that OP-induced neuronal hyperactivation was markedly reduced in larvae fully devoid of microglia. DFP poisoning rapidly triggered massive microglia-mediated neuroinflammation, probably as a result of DFP-induced neuronal hyperexcitation, which in turn further exacerbated neuronal activation. Microglia are thus a relevant therapeutic target, and identifying substances reducing microglial activation could add efficacy to existing OP antidote cocktails.
Collapse
|
11
|
Time-dependent neuropathology in rats following organophosphate-induced status epilepticus. Neurotoxicology 2022; 91:45-59. [DOI: 10.1016/j.neuro.2022.04.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 04/11/2022] [Accepted: 04/24/2022] [Indexed: 11/17/2022]
|
12
|
Rodríguez-Massó SR, Erickson MA, Banks WA, Ulrich H, Martins AH. The Bradykinin B2 Receptor Agonist (NG291) Causes Rapid Onset of Transient Blood-Brain Barrier Disruption Without Evidence of Early Brain Injury. Front Neurosci 2021; 15:791709. [PMID: 34975388 PMCID: PMC8715084 DOI: 10.3389/fnins.2021.791709] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 11/15/2021] [Indexed: 12/12/2022] Open
Abstract
Background: The blood-brain barrier (BBB) describes the brain's highly specialized capillaries, which form a dynamic interface that maintains central nervous system (CNS) homeostasis. The BBB supports the CNS, in part, by preventing the entry of potentially harmful circulating molecules into the brain. However, this specialized function is challenging for the development of CNS therapeutics. Several strategies to facilitate drug delivery into the brain parenchyma via disruption of the BBB have been proposed. Bradykinin has proven effective in disrupting mechanisms across the blood-tumor barrier. Unfortunately, bradykinin has limited therapeutic value because of its short half-life and the undesirable biological activity elicited by its active metabolites. Objective: To evaluate NG291, a stable bradykinin analog, with selective agonist activity on the bradykinin-B2 receptor and its ability to disrupt the BBB transiently. Methods: Sprague Dawley rats and CD-1 mice were subjected to NG291 treatment (either 50 or 100 μg/kg, intravenously). Time and dose-dependent BBB disruption were evaluated by histological analysis of Evans blue (EB) extravasation. Transcellular and paracellular BBB leakage were assessed by infiltration of 99mTc-albumin (66.5 KDa) and 14C-sucrose (340 Da) radiolabeled probes into the brains of CD-1 mice treated with NG291. NG291 influence on P-glycoprotein (P-gp) efflux pump activity was evaluated by quantifying the brain accumulation of 3H-verapamil, a known P-gp substrate, in CD-1 mice. Results: NG291-mediated BBB disruption was localized, dose-dependent, and reversible as measured by EB extravasation. 99mTc-albumin leakage was significantly increased by 50 μg/kg of NG291, whereas 100 μg/kg of NG291 significantly augmented both 14C-sucrose and 99mTc-albumin leakage. NG291 enhanced P-gp efflux transporter activity and was unable to increase brain uptake of the P-gp substrate pralidoxime. NG291 did not evoke significant short-term neurotoxicity, as it did not increase brain water content, the number of Fluoro-Jade C positive cells, or astrocyte activation. Conclusion: Our findings strongly suggest that NG291 increases BBB permeability by two different mechanisms in a dose-dependent manner and increases P-gp efflux transport. This increased permeability may facilitate the penetration into the brain of therapeutic candidates that are not P-gp substrates.
Collapse
Affiliation(s)
- Sergio R. Rodríguez-Massó
- Department of Pharmacology and Toxicology, University of Puerto Rico Medical Sciences Campus, San Juan, PR, United States
| | - Michelle A. Erickson
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA, United States
- Division of Gerontology and Geriatric Medicine, Department of Medicine, School of Medicine, University of Washington, Seattle, WA, United States
| | - William A. Banks
- Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA, United States
- Division of Gerontology and Geriatric Medicine, Department of Medicine, School of Medicine, University of Washington, Seattle, WA, United States
| | - Henning Ulrich
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | - Antonio Henrique Martins
- Department of Pharmacology and Toxicology, University of Puerto Rico Medical Sciences Campus, San Juan, PR, United States
| |
Collapse
|
13
|
Calsbeek JJ, González EA, Bruun DA, Guignet MA, Copping N, Dawson ME, Yu AJ, MacMahon JA, Saito NH, Harvey DJ, Silverman JL, Lein PJ. Persistent neuropathology and behavioral deficits in a mouse model of status epilepticus induced by acute intoxication with diisopropylfluorophosphate. Neurotoxicology 2021; 87:106-119. [PMID: 34509511 PMCID: PMC8595753 DOI: 10.1016/j.neuro.2021.09.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 08/27/2021] [Accepted: 09/06/2021] [Indexed: 01/01/2023]
Abstract
Organophosphate (OP) nerve agents and pesticides are a class of neurotoxic compounds that can cause status epilepticus (SE), and death following acute high-dose exposures. While the standard of care for acute OP intoxication (atropine, oxime, and high-dose benzodiazepine) can prevent mortality, survivors of OP poisoning often experience long-term brain damage and cognitive deficits. Preclinical studies of acute OP intoxication have primarily used rat models to identify candidate medical countermeasures. However, the mouse offers the advantage of readily available knockout strains for mechanistic studies of acute and chronic consequences of OP-induced SE. Therefore, the main objective of this study was to determine whether a mouse model of acute diisopropylfluorophosphate (DFP) intoxication would produce acute and chronic neurotoxicity similar to that observed in rat models and humans following acute OP intoxication. Adult male C57BL/6J mice injected with DFP (9.5 mg/kg, s.c.) followed 1 min later with atropine sulfate (0.1 mg/kg, i.m.) and 2-pralidoxime (25 mg/kg, i.m.) developed behavioral and electrographic signs of SE within minutes that continued for at least 4 h. Acetylcholinesterase inhibition persisted for at least 3 d in the blood and 14 d in the brain of DFP mice relative to vehicle (VEH) controls. Immunohistochemical analyses revealed significant neurodegeneration and neuroinflammation in multiple brain regions at 1, 7, and 28 d post-exposure in the brains of DFP mice relative to VEH controls. Deficits in locomotor and home-cage behavior were observed in DFP mice at 28 d post-exposure. These findings demonstrate that this mouse model replicates many of the outcomes observed in rats and humans acutely intoxicated with OPs, suggesting the feasibility of using this model for mechanistic studies and therapeutic screening.
Collapse
Affiliation(s)
- Jonas J Calsbeek
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, USA.
| | - Eduardo A González
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, USA.
| | - Donald A Bruun
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, USA.
| | - Michelle A Guignet
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, USA.
| | - Nycole Copping
- Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California, Davis, Sacramento, CA, 95817, USA; MIND Institute, School of Medicine, University of California, Davis, Sacramento, CA, 95817, USA.
| | - Mallory E Dawson
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, USA.
| | - Alexandria J Yu
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, USA.
| | - Jeremy A MacMahon
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, USA.
| | - Naomi H Saito
- Department of Public Health Sciences, University of California, Davis, School of Medicine, Davis, CA, 95616, USA.
| | - Danielle J Harvey
- Department of Public Health Sciences, University of California, Davis, School of Medicine, Davis, CA, 95616, USA.
| | - Jill L Silverman
- Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California, Davis, Sacramento, CA, 95817, USA; MIND Institute, School of Medicine, University of California, Davis, Sacramento, CA, 95817, USA.
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, USA; MIND Institute, School of Medicine, University of California, Davis, Sacramento, CA, 95817, USA.
| |
Collapse
|
14
|
Rojas A, McCarren HS, Wang J, Wang W, Abreu-Melon J, Wang S, McDonough JH, Dingledine R. Comparison of neuropathology in rats following status epilepticus induced by diisopropylfluorophosphate and soman. Neurotoxicology 2021; 83:14-27. [PMID: 33352274 PMCID: PMC7987879 DOI: 10.1016/j.neuro.2020.12.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 12/07/2020] [Accepted: 12/16/2020] [Indexed: 12/29/2022]
Abstract
The increasing number of cases involving the use of nerve agents as deadly weapons has spurred investigation into the molecular mechanisms underlying nerve agent-induced pathology. The highly toxic nature of nerve agents restrict their use in academic research laboratories. Less toxic organophosphorus (OP) based agents including diisopropylfluorophosphate (DFP) are used as surrogates in academic research laboratories to mimic nerve agent poisoning. However, neuropathology resulting from DFP-induced status epilepticus (SE) has not been compared directly to neuropathology observed following nerve agent poisoning in the same study. Here, the hypothesis that neuropathology measured four days after SE is the same for rats exposed to DFP and soman was tested. Adult Sprague-Dawley rats were injected with soman or DFP to induce SE. Cortical electroencephalography (EEG) was recorded prior to and during soman-induced SE. EEG power analysis of rats administered soman revealed prolonged electrographic SE similar to that of rats that endure uninterrupted SE following injection of DFP. Rats that experienced soman-induced SE displayed less hippocampal neuroinflammation and gliosis compared to rats administered DFP. Seizure-induced weight change, blood-brain barrier (BBB) leakiness and neurodegeneration in most seizure sensitive limbic brain regions were similar for rats that endured SE following soman or DFP. The amalgamated pathology score calculated by combining pathological measures (weight loss, hippocampal neuroinflammation, gliosis, BBB integrity and neurodegeneration) was similar in rats administered the OP agents. These findings support use of the rat DFP model of SE as a suitable surrogate for investigating some, but not all delayed consequences produced by nerve agents.
Collapse
Affiliation(s)
- Asheebo Rojas
- Department of Pharmacology and Chemical Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA, 30322, United States.
| | - Hilary S McCarren
- Neuroscience Department, Medical Toxicology Research Division, United States Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd, Aberdeen Proving Ground, MD, 21010, United States
| | - Jennifer Wang
- Department of Pharmacology and Chemical Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA, 30322, United States
| | - Wenyi Wang
- Department of Pharmacology and Chemical Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA, 30322, United States
| | - JuanMartin Abreu-Melon
- Department of Pharmacology and Chemical Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA, 30322, United States
| | - Sarah Wang
- Department of Pharmacology and Chemical Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA, 30322, United States
| | - John H McDonough
- Neuroscience Department, Medical Toxicology Research Division, United States Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Rd, Aberdeen Proving Ground, MD, 21010, United States
| | - Raymond Dingledine
- Department of Pharmacology and Chemical Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA, 30322, United States
| |
Collapse
|
15
|
Maupu C, Enderlin J, Igert A, Oger M, Auvin S, Hassan-Abdi R, Soussi-Yanicostas N, Brazzolotto X, Nachon F, Dal Bo G, Dupuis N. Diisopropylfluorophosphate-induced status epilepticus drives complex glial cell phenotypes in adult male mice. Neurobiol Dis 2021; 152:105276. [PMID: 33529768 DOI: 10.1016/j.nbd.2021.105276] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 12/14/2020] [Accepted: 01/24/2021] [Indexed: 12/11/2022] Open
Abstract
Organophosphate pesticides and nerve agents (OPs), are characterized by cholinesterase inhibition. In addition to severe peripheral symptoms, high doses of OPs can lead to seizures and status epilepticus (SE). Long lasting seizure activity and subsequent neurodegeneration promote neuroinflammation leading to profound pathological alterations of the brain. The aim of this study was to characterize neuroinflammatory responses at key time points after SE induced by the OP, diisopropylfluorophosphate (DFP). Immunohistochemistry (IHC) analysis and RT-qPCR on cerebral tissue are often insufficient to identity and quantify precise neuroinflammatory alterations. To address these needs, we performed RT-qPCR quantification after whole brain magnetic-activated cell-sorting (MACS) of CD11B (microglia/infiltrated macrophages) and GLAST (astrocytes)-positive cells at 1, 4, 24 h and 3 days post-SE. In order to compare these results to those obtained by IHC, we performed, classical Iba1 (microglia/infiltrated macrophages) and GFAP (astrocytes) IHC analysis in parallel, focusing on the hippocampus, a brain region affected by seizure activity and neurodegeneration. Shortly after SE (1-4 h), an increase in pro-inflammatory (M1-like) markers and A2-specific markers, proposed as neurotrophic, were observed in CD11B and GLAST-positive isolated cells, respectively. Microglial cells successively expressed immuno-regulatory (M2b-like) and anti-inflammatory (M2a-like) at 4 h and 24 h post-SE induction. At 24 h and 3 days, A1-specific markers, proposed as neurotoxic, were increased in isolated astrocytes. Although IHC analysis presented no modification in terms of percentage of marked area and cell number at 1 and 4 h after SE, at 24 h and 3 days after SE, microglial and astrocytic activation was visible by IHC as an increase in Iba1 and GFAP-positive area and Iba1-positive cells in DFP animals when compared to the control. Our work identified sequential microglial and astrocytic phenotype activation. Although the role of each phenotype in SE cerebral outcomes requires further study, targeting specific markers at specific time point could be a beneficial strategy for DFP-induced SE treatment.
Collapse
Affiliation(s)
- Clémence Maupu
- Département de Toxicologie et risques chimiques, Institut de recherche biomédicale des armées, BP73, F-91223 Brétigny sur Orge cedex, France
| | - Julie Enderlin
- Université de Paris, NeuroDiderot, Inserm, F-75019 Paris, France; Service de neurologie pédiatrique, AP-HP, Hôpital Robert Debré, F-75019 Paris, France
| | - Alexandre Igert
- Département de Toxicologie et risques chimiques, Institut de recherche biomédicale des armées, BP73, F-91223 Brétigny sur Orge cedex, France
| | - Myriam Oger
- Unité Imagerie, Institut de recherche biomédicale des armées, BP73, F-91223 Brétigny sur Orge cedex, France
| | - Stéphane Auvin
- Université de Paris, NeuroDiderot, Inserm, F-75019 Paris, France; Service de neurologie pédiatrique, AP-HP, Hôpital Robert Debré, F-75019 Paris, France
| | | | | | - Xavier Brazzolotto
- Département de Toxicologie et risques chimiques, Institut de recherche biomédicale des armées, BP73, F-91223 Brétigny sur Orge cedex, France
| | - Florian Nachon
- Département de Toxicologie et risques chimiques, Institut de recherche biomédicale des armées, BP73, F-91223 Brétigny sur Orge cedex, France
| | - Grégory Dal Bo
- Département de Toxicologie et risques chimiques, Institut de recherche biomédicale des armées, BP73, F-91223 Brétigny sur Orge cedex, France
| | - Nina Dupuis
- Département de Toxicologie et risques chimiques, Institut de recherche biomédicale des armées, BP73, F-91223 Brétigny sur Orge cedex, France.
| |
Collapse
|
16
|
Brenet A, Somkhit J, Hassan-Abdi R, Yanicostas C, Romain C, Bar O, Igert A, Saurat D, Taudon N, Dal-Bo G, Nachon F, Dupuis N, Soussi-Yanicostas N. Organophosphorus diisopropylfluorophosphate (DFP) intoxication in zebrafish larvae causes behavioral defects, neuronal hyperexcitation and neuronal death. Sci Rep 2020; 10:19228. [PMID: 33154418 PMCID: PMC7645799 DOI: 10.1038/s41598-020-76056-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 10/19/2020] [Indexed: 11/09/2022] Open
Abstract
With millions of intoxications each year and over 200,000 deaths, organophosphorus (OP) compounds are an important public health issue worldwide. OP poisoning induces cholinergic syndrome, with respiratory distress, hypertension, and neuron damage that may lead to epileptic seizures and permanent cognitive deficits. Existing countermeasures are lifesaving but do not prevent long-lasting neuronal comorbidities, emphasizing the urgent need for animal models to better understand OP neurotoxicity and identify novel antidotes. Here, using diisopropylfluorophosphate (DFP), a prototypic and moderately toxic OP, combined with zebrafish larvae, we first showed that DFP poisoning caused major acetylcholinesterase inhibition, resulting in paralysis and CNS neuron hyperactivation, as indicated by increased neuronal calcium transients and overexpression of the immediate early genes fosab, junBa, npas4b, and atf3. In addition to these epileptiform seizure-like events, DFP-exposed larvae showed increased neuronal apoptosis, which were both partially alleviated by diazepam treatment, suggesting a causal link between neuronal hyperexcitation and cell death. Last, DFP poisoning induced an altered balance of glutamatergic/GABAergic synaptic activity with increased NR2B-NMDA receptor accumulation combined with decreased GAD65/67 and gephyrin protein accumulation. The zebrafish DFP model presented here thus provides important novel insights into the pathophysiology of OP intoxication, making it a promising model to identify novel antidotes.
Collapse
Affiliation(s)
| | - Julie Somkhit
- NeuroDiderot, Inserm, Université de Paris, 75019, Paris, France
| | | | | | | | - Olivier Bar
- NeuroDiderot, Inserm, Université de Paris, 75019, Paris, France
| | - Alexandre Igert
- Département de toxicologie et risques chimiques, Institut de Recherche Biomédicale des Armées (IRBA), 91 220, Brétigny-sur-Orge, France
| | - Dominique Saurat
- Institut de Recherche Biomédicale des Armées (IRBA), Unité de Développements Analytiques et Bioanalyse, 91 220, Brétigny-sur-Orge, France
| | - Nicolas Taudon
- Institut de Recherche Biomédicale des Armées (IRBA), Unité de Développements Analytiques et Bioanalyse, 91 220, Brétigny-sur-Orge, France
| | - Gregory Dal-Bo
- Département de toxicologie et risques chimiques, Institut de Recherche Biomédicale des Armées (IRBA), 91 220, Brétigny-sur-Orge, France
| | - Florian Nachon
- Département de toxicologie et risques chimiques, Institut de Recherche Biomédicale des Armées (IRBA), 91 220, Brétigny-sur-Orge, France
| | - Nina Dupuis
- Département de toxicologie et risques chimiques, Institut de Recherche Biomédicale des Armées (IRBA), 91 220, Brétigny-sur-Orge, France
| | | |
Collapse
|
17
|
Dhir A, Bruun DA, Guignet M, Tsai Y, González E, Calsbeek J, Vu J, Saito N, Tancredi DJ, Harvey DJ, Lein PJ, Rogawski MA. Allopregnanolone and perampanel as adjuncts to midazolam for treating diisopropylfluorophosphate-induced status epilepticus in rats. Ann N Y Acad Sci 2020; 1480:183-206. [PMID: 32915470 PMCID: PMC7756871 DOI: 10.1111/nyas.14479] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/29/2020] [Accepted: 08/06/2020] [Indexed: 12/11/2022]
Abstract
Combinations of midazolam, allopregnanolone, and perampanel were assessed for antiseizure activity in a rat diisopropylfluorophosphate (DFP) status epilepticus model. Animals receiving DFP followed by atropine and pralidoxime exhibited continuous high-amplitude rhythmical electroencephalography (EEG) spike activity and behavioral seizures for more than 5 hours. Treatments were administered intramuscularly 40 min after DFP. Seizures persisted following midazolam (1.8 mg/kg). The combination of midazolam with either allopregnanolone (6 mg/kg) or perampanel (2 mg/kg) terminated EEG and behavioral status epilepticus, but the onset of the perampanel effect was slow. The combination of midazolam, allopregnanolone, and perampanel caused rapid and complete suppression of EEG and behavioral seizures. In the absence of DFP, animals treated with the three-drug combination were sedated but not anesthetized. Animals that received midazolam alone exhibited spontaneous recurrent EEG seizures, whereas those that received the three-drug combination did not, demonstrating antiepileptogenic activity. All combination treatments reduced neurodegeneration as assessed with Fluoro-Jade C staining to a greater extent than midazolam alone, and most reduced astrogliosis as assessed by GFAP immunoreactivity but had mixed effects on markers of microglial activation. We conclude that allopregnanolone, a positive modulator of the GABAA receptor, and perampanel, an AMPA receptor antagonist, are potential adjuncts to midazolam in the treatment of benzodiazepine-refractory organophosphate nerve agent-induced status epilepticus.
Collapse
Affiliation(s)
- Ashish Dhir
- Department of Neurology, School of MedicineUniversity of California, DavisSacramentoCalifornia
| | - Donald A. Bruun
- Department of Molecular Biosciences, School of Veterinary MedicineUniversity of California, DavisDavisCalifornia
| | - Michelle Guignet
- Department of Molecular Biosciences, School of Veterinary MedicineUniversity of California, DavisDavisCalifornia
| | - Yi‐Hua Tsai
- Department of Molecular Biosciences, School of Veterinary MedicineUniversity of California, DavisDavisCalifornia
| | - Eduardo González
- Department of Molecular Biosciences, School of Veterinary MedicineUniversity of California, DavisDavisCalifornia
| | - Jonas Calsbeek
- Department of Molecular Biosciences, School of Veterinary MedicineUniversity of California, DavisDavisCalifornia
| | - Joan Vu
- Department of Molecular Biosciences, School of Veterinary MedicineUniversity of California, DavisDavisCalifornia
| | - Naomi Saito
- Department of Public Health Sciences, School of MedicineUniversity of California, DavisDavisCalifornia
| | - Daniel J. Tancredi
- Department of Pediatrics, School of MedicineUniversity of California, DavisSacramentoCalifornia
| | - Danielle J. Harvey
- Department of Public Health Sciences, School of MedicineUniversity of California, DavisDavisCalifornia
| | - Pamela J. Lein
- Department of Molecular Biosciences, School of Veterinary MedicineUniversity of California, DavisDavisCalifornia
| | - Michael A. Rogawski
- Department of Neurology, School of MedicineUniversity of California, DavisSacramentoCalifornia
| |
Collapse
|
18
|
Rojas A, Wang J, Glover A, Dingledine R. Urethane attenuates early neuropathology of diisopropylfluorophosphate-induced status epilepticus in rats. Neurobiol Dis 2020; 140:104863. [PMID: 32283202 PMCID: PMC7266093 DOI: 10.1016/j.nbd.2020.104863] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 02/17/2020] [Accepted: 04/02/2020] [Indexed: 12/27/2022] Open
Abstract
Seizures can be evident within minutes of exposure to an organophosphorus (OP) agent and often progress to status epilepticus (SE) resulting in a high mortality if left untreated. Effective medical countermeasures are necessary to sustain patients suffering from OP poisoning and to mitigate the ensuing brain injury. Here, the hypothesis was tested that a single subanesthetic dose of urethane prevents neuropathology measured 24 h following diisopropylfluorophosphate (DFP)-induced SE. Adult Sprague-Dawley rats were injected with DFP to induce SE. During SE rats displayed increased neuronal activity in the hippocampus and an upregulation of immediate early genes as well as pro-inflammatory mediators. In additional experiments rats were administered diazepam (10 mg/kg, ip) or urethane (0.8 g/kg, sc) 1 h after DFP-induced SE and compared to rats that experienced uninterrupted SE. Cortical electroencephalography (EEG) and power analysis strengthen the conclusion that urethane effectively terminates SE and prevents the overnight return of seizure activity. Neurodegeneration in limbic brain regions and the seizure-induced upregulation of key inflammatory mediators present 24 h after DFP-induced SE were strongly attenuated by administration of urethane. A trivial explanation for these beneficial effects, that urethane simply reactivates acetylcholinesterase, has been ruled out. These findings indicate that, by contrast to rats administered diazepam or rats that experience uninterrupted SE, the early neuropathology after SE is prevented by subanesthetic urethane, which terminates rather than interrupts, SE.
Collapse
Affiliation(s)
- Asheebo Rojas
- Department of Pharmacology and Chemical Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, United States of America.
| | - Jennifer Wang
- Department of Pharmacology and Chemical Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, United States of America
| | - Avery Glover
- Department of Pharmacology and Chemical Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, United States of America
| | - Raymond Dingledine
- Department of Pharmacology and Chemical Biology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, United States of America
| |
Collapse
|
19
|
González EA, Rindy AC, Guignet MA, Calsbeek JJ, Bruun DA, Dhir A, Andrew P, Saito N, Rowland DJ, Harvey DJ, Rogawski MA, Lein PJ. The chemical convulsant diisopropylfluorophosphate (DFP) causes persistent neuropathology in adult male rats independent of seizure activity. Arch Toxicol 2020; 94:2149-2162. [PMID: 32303805 PMCID: PMC7305973 DOI: 10.1007/s00204-020-02747-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Accepted: 04/08/2020] [Indexed: 12/27/2022]
Abstract
Organophosphate (OP) threat agents can trigger seizures that progress to status epilepticus, resulting in persistent neuropathology and cognitive deficits in humans and preclinical models. However, it remains unclear whether patients who do not show overt seizure behavior develop neurological consequences. Therefore, this study compared two subpopulations of rats with a low versus high seizure response to diisopropylfluorophosphate (DFP) to evaluate whether acute OP intoxication causes persistent neuropathology in non-seizing individuals. Adult male Sprague Dawley rats administered DFP (4 mg/kg, sc), atropine sulfate (2 mg/kg, im), and pralidoxime (25 mg/kg, im) were monitored for seizure activity for 4 h post-exposure. Animals were separated into groups with low versus high seizure response based on behavioral criteria and electroencephalogram (EEG) recordings. Cholinesterase activity was evaluated by Ellman assay, and neuropathology was evaluated at 1, 2, 4, and 60 days post-exposure by Fluoro-Jade C (FJC) staining and micro-CT imaging. DFP significantly inhibited cholinesterase activity in the cortex, hippocampus, and amygdala to the same extent in low and high responders. FJC staining revealed significant neurodegeneration in DFP low responders albeit this response was delayed, less persistent, and decreased in magnitude compared to DFP high responders. Micro-CT scans at 60 days revealed extensive mineralization that was not significantly different between low versus high DFP responders. These findings highlight the importance of considering non-seizing patients for medical care in the event of acute OP intoxication. They also suggest that OP intoxication may induce neurological damage via seizure-independent mechanisms, which if identified, might provide insight into novel therapeutic targets.
Collapse
Affiliation(s)
- Eduardo A González
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA
| | - Alexa C Rindy
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA
| | - Michelle A Guignet
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA
| | - Jonas J Calsbeek
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA
| | - Donald A Bruun
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA
| | - Ashish Dhir
- Department of Neurology, University of California, Davis, School of Medicine, 4860 Y Street, Sacramento, CA, 95817, USA
| | - Peter Andrew
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA
| | - Naomi Saito
- Department of Public Health Sciences, University of California, Davis, School of Medicine, One Shields Avenue, Davis, CA, 95616, USA
| | - Douglas J Rowland
- Center for Molecular and Genomic Imaging, University of California, Davis, College of Engineering, 451 Health Sciences Drive, Davis, CA, 95616, USA
| | - Danielle J Harvey
- Department of Public Health Sciences, University of California, Davis, School of Medicine, One Shields Avenue, Davis, CA, 95616, USA
| | - Michael A Rogawski
- Department of Neurology, University of California, Davis, School of Medicine, 4860 Y Street, Sacramento, CA, 95817, USA
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA.
| |
Collapse
|
20
|
Zare Z, Zarbakhsh S, Tehrani M, Mohammadi M. Paraoxon-induced damage in rat hippocampus is associated with alterations in the expression of apoptosis-related proteins. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2020; 166:104580. [PMID: 32448426 DOI: 10.1016/j.pestbp.2020.104580] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 03/02/2020] [Accepted: 04/06/2020] [Indexed: 06/11/2023]
Abstract
To determine the possible role of apoptosis in the development of paraoxon-induced brain damage, we evaluated expression of apoptosis-related proteins, the extent of neuronal damage, and activation of astrocytes in rat hippocampus. Adult male Wistar rats were intraperitoneally injected with one of three doses of paraoxon (0.3, 0.7, or 1 mg/kg) or corn oil (vehicle). After 14 or 28 days, expression of apoptosis-related proteins, including B-cell leukemia/lymphoma-2 (Bcl-2), Bcl-2 associated X protein (Bax), and caspase-3, as well as the number of neurons and glial fibrillary acidic protein (GFAP) positive cells in hippocampus were examined by western blot, cresyl blue staining, and immunohistochemistry, respectively. After 14 and 28 days, Bax and caspase-3 proteins were significantly increased in rats receiving 0.7 and 1 mg/kg of paraoxon. A significant decrease in Bcl-2 protein levels was also observed in 0.7 and 1 mg/kg groups after 14 days and in 1 mg/kg group after 28 days. Animals treated with 1 mg/kg of paraoxon showed a significant decrease in the number of neurons in the CA1 area. Also, those treated with 0.7 and 1 mg/kg of paraoxon showed an increase in the number of GFAP positive cells in both CA1 and CA3 areas as well as a significant decrease in survived neurons in the CA3 area. Our results indicated that neuronal damage induced by convulsive doses of paraoxon in rat hippocampus is mediated in part through apoptosis mechanism. Activation of astrocytes might lead to reduced extent of damage and damage and consequently increased neuronal survival.
Collapse
Affiliation(s)
- Zohreh Zare
- Department of Anatomical Sciences, Molecular and Cell Biology Research Center, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - Sam Zarbakhsh
- Nervous System Stem Cells Research Center, Semnan University of Medical Sciences, Semnan, Iran
| | - Mohsen Tehrani
- Department of Immunology, Gastrointestinal Cancer Research Center, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - Moslem Mohammadi
- Department of Physiology, Molecular and Cell Biology Research Center, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.
| |
Collapse
|
21
|
Enderlin J, Igert A, Auvin S, Nachon F, Dal Bo G, Dupuis N. Characterization of organophosphate-induced brain injuries in a convulsive mouse model of diisopropylfluorophosphate exposure. Epilepsia 2020; 61:e54-e59. [PMID: 32359085 DOI: 10.1111/epi.16516] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 04/05/2020] [Accepted: 04/06/2020] [Indexed: 11/30/2022]
Abstract
Organophosphate (OP) compounds constitute a class of highly toxic molecules, characterized by irreversible cholinesterase (ChE) inhibition. Being either pesticides or chemical warfare agents, they present a major health issue in some countries, as well as a terrorist or military threat. Prompted by the need for suitable animal models to test novel medical countermeasures, we developed a new convulsive mouse model of OP poisoning using diisopropylfluorophosphate (DFP). Using electrocorticography (ECoG), we analyzed seizure and status epilepticus (SE) occurrences, as well as relative power of ECoG frequency band modifications after DFP injection in male Swiss mice. Next, we investigated DFP effect on ChE inhibition. Histological changes on neuronal activity and neuronal damage were examined by c-Fos immunolabeling and Fluoro-Jade C staining. We showed that mice exposed to DFP presented electrocorticographic seizures that rapidly progressed to SE within 20 minutes. Lasting >8 hours, DFP-induced SE was associated with major power spectrum modifications in seizing DFP animals compared to control animals. Seizures and SE development were concomitant with profound ChE inhibition and induced massive neuronal degeneration. Presenting all hallmarks of convulsive OP poisoning, we showed that our mouse model is valuable for studying pathophysiological mechanisms and preclinical testing of newly available therapeutic molecules.
Collapse
Affiliation(s)
- Julie Enderlin
- NeuroDiderot, Inserm U1141, Sorbonne Paris Cité, Paris Diderot University, Paris, France.,Pediatric Neurology Department, Robert Debré Hospital, Public Hospital Network of Paris, Paris, France
| | - Alexandre Igert
- Department of Toxicology and Chemical Risks, Institute for Biomedical Research of the Armed Forces, Brétigny sur Orge, France
| | - Stéphane Auvin
- NeuroDiderot, Inserm U1141, Sorbonne Paris Cité, Paris Diderot University, Paris, France.,Pediatric Neurology Department, Robert Debré Hospital, Public Hospital Network of Paris, Paris, France
| | - Florian Nachon
- Department of Toxicology and Chemical Risks, Institute for Biomedical Research of the Armed Forces, Brétigny sur Orge, France
| | - Grégory Dal Bo
- Department of Toxicology and Chemical Risks, Institute for Biomedical Research of the Armed Forces, Brétigny sur Orge, France
| | - Nina Dupuis
- Department of Toxicology and Chemical Risks, Institute for Biomedical Research of the Armed Forces, Brétigny sur Orge, France
| |
Collapse
|
22
|
Gage M, Golden M, Putra M, Sharma S, Thippeswamy T. Sex as a biological variable in the rat model of diisopropylfluorophosphate-induced long-term neurotoxicity. Ann N Y Acad Sci 2020; 1479:44-64. [PMID: 32090337 DOI: 10.1111/nyas.14315] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 01/24/2020] [Accepted: 01/25/2020] [Indexed: 01/13/2023]
Abstract
Sex differences in response to neurotoxicant exposure that initiates epileptogenesis are understudied. We used telemetry-implanted male and female adult rats exposed to an organophosphate (OP) neurotoxicant, diisopropylflourophosphate (DFP), to test sex differences in the severity of status epilepticus (SE) and the development of spontaneous recurrent seizures (SRS). Females had significantly less severe SE and decreased epileptiform spikes compared with males, although females received a higher dose of DFP than males. The estrous stages had no impact on seizure susceptibility, but rats with severe SE had a significantly prolonged diestrus. A previously demonstrated disease-modifying agent, an inducible nitric oxide synthase inhibitor, 1400W, was tested in both sexes. None of the eight males treated with 1400W developed convulsive SRS during 4 weeks post-DFP exposure, while two of seven females developed convulsive SRS. Concerning gliosis and neurodegeneration, there were region-specific differences in the interaction between sex and SE severity. As SE severity influences epileptogenesis, and as females had significantly less severe SE, sex as a biological variable should be factored into the design of future OP nerve agent experiments while evaluating neurotoxicity and optimizing potential disease-modifying agents.
Collapse
Affiliation(s)
- Meghan Gage
- Epilepsy Research Laboratory, Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, Iowa
| | - Madison Golden
- Epilepsy Research Laboratory, Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, Iowa
| | - Marson Putra
- Epilepsy Research Laboratory, Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, Iowa
| | - Shaunik Sharma
- Epilepsy Research Laboratory, Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, Iowa
| | - Thimmasettappa Thippeswamy
- Epilepsy Research Laboratory, Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, Iowa
| |
Collapse
|
23
|
Guignet M, Dhakal K, Flannery BM, Hobson BA, Zolkowska D, Dhir A, Bruun DA, Li S, Wahab A, Harvey DJ, Silverman JL, Rogawski MA, Lein PJ. Persistent behavior deficits, neuroinflammation, and oxidative stress in a rat model of acute organophosphate intoxication. Neurobiol Dis 2020; 133:104431. [PMID: 30905768 PMCID: PMC6754818 DOI: 10.1016/j.nbd.2019.03.019] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 03/05/2019] [Accepted: 03/20/2019] [Indexed: 01/24/2023] Open
Abstract
Current medical countermeasures for organophosphate (OP)-induced status epilepticus (SE) are not effective in preventing long-term morbidity and there is an urgent need for improved therapies. Rat models of acute intoxication with the OP, diisopropylfluorophosphate (DFP), are increasingly being used to evaluate therapeutic candidates for efficacy in mitigating the long-term neurologic effects associated with OP-induced SE. Many of these therapeutic candidates target neuroinflammation and oxidative stress because of their implication in the pathogenesis of persistent neurologic deficits associated with OP-induced SE. Critical to these efforts is the rigorous characterization of the rat DFP model with respect to outcomes associated with acute OP intoxication in humans, which include long-term electroencephalographic, neurobehavioral, and neuropathologic effects, and their temporal relationship to neuroinflammation and oxidative stress. To address these needs, we examined a range of outcomes at later times post-exposure than have previously been reported for this model. Adult male Sprague-Dawley rats were given pyridostigmine bromide (0.1 mg/kg, im) 30 min prior to administration of DFP (4 mg/kg, sc), which was immediately followed by atropine sulfate (2 mg/kg, im) and pralidoxime (25 mg/kg, im). This exposure paradigm triggered robust electroencephalographic and behavioral seizures that rapidly progressed to SE lasting several hours in 90% of exposed animals. Animals that survived DFP-induced SE (~70%) exhibited spontaneous recurrent seizures and hyperreactive responses to tactile stimuli over the first 2 months post-exposure. Performance in the elevated plus maze, open field, and Pavlovian fear conditioning tests indicated that acute DFP intoxication reduced anxiety-like behavior and impaired learning and memory at 1 and 2 months post-exposure in the absence of effects on general locomotor behavior. Immunohistochemical analyses revealed significantly increased expression of biomarkers of reactive astrogliosis, microglial activation and oxidative stress in multiple brain regions at 1 and 2 months post-DFP, although there was significant spatiotemporal heterogeneity across these endpoints. Collectively, these data largely support the relevance of the rat model of acute DFP intoxication as a model for acute OP intoxication in the human, and support the hypothesis that neuroinflammation and/or oxidative stress represent potential therapeutic targets for mitigating the long-term neurologic sequelae of acute OP intoxication.
Collapse
Affiliation(s)
- Michelle Guignet
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, 1089 Veterinary Medicine Drive, Davis, CA, 95616 USA, , , , , ,
| | - Kiran Dhakal
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, 1089 Veterinary Medicine Drive, Davis, CA, 95616 USA, , , , , ,
| | - Brenna M. Flannery
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, 1089 Veterinary Medicine Drive, Davis, CA, 95616 USA, , , , , ,
| | - Brad A. Hobson
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, 1089 Veterinary Medicine Drive, Davis, CA, 95616 USA, , , , , ,
| | - Dorota Zolkowska
- Department of Neurology, School of Medicine, University of California-Davis, 4860 Y Street, Sacramento, CA 95817 USA, , , ;
| | - Ashish Dhir
- Department of Neurology, School of Medicine, University of California-Davis, 4860 Y Street, Sacramento, CA 95817 USA, , , ;
| | - Donald A. Bruun
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, 1089 Veterinary Medicine Drive, Davis, CA, 95616 USA, , , , , ,
| | - Shuyang Li
- Department of Public Health Sciences, University of California-Davis, One Shields Avenue, Davis, CA 95616 USA, ,
| | - Abdul Wahab
- Department of Neurology, School of Medicine, University of California-Davis, 4860 Y Street, Sacramento, CA 95817 USA, , , ;
| | - Danielle J. Harvey
- Department of Public Health Sciences, University of California-Davis, One Shields Avenue, Davis, CA 95616 USA, ,
| | - Jill L. Silverman
- Department of Psychiatry and Behavioral Sciences, School of Medicine, University of California-Davis, 2230 Stockton Boulevard, Sacramento, CA 95817 USA,
- MIND Institute, School of Medicine, University of California-Davis, 2825 50 Street, Sacramento, CA 95817 USA
| | - Michael A. Rogawski
- Department of Neurology, School of Medicine, University of California-Davis, 4860 Y Street, Sacramento, CA 95817 USA, , , ;
| | - Pamela J. Lein
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, 1089 Veterinary Medicine Drive, Davis, CA, 95616 USA, , , , , ,
- MIND Institute, School of Medicine, University of California-Davis, 2825 50 Street, Sacramento, CA 95817 USA
| |
Collapse
|
24
|
Younis N, Mohamed M. Sandalwood oil neuroprotective effects on middle cerebral artery occlusion model of ischemic brain stroke. Pharmacogn Mag 2020. [DOI: 10.4103/pm.pm_398_19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
|
25
|
Rojas A, Ganesh T, Wang W, Wang J, Dingledine R. A rat model of organophosphate-induced status epilepticus and the beneficial effects of EP2 receptor inhibition. Neurobiol Dis 2020; 133:104399. [PMID: 30818067 PMCID: PMC6708729 DOI: 10.1016/j.nbd.2019.02.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 01/29/2019] [Accepted: 02/20/2019] [Indexed: 02/06/2023] Open
Abstract
This review describes an adult rat model of status epilepticus (SE) induced by diisopropyl fluorophosphate (DFP), and the beneficial outcomes of transient inhibition of the prostaglandin-E2 receptor EP2 with a small molecule antagonist, delayed by 2-4 h after SE onset. Administration of six doses of the selective EP2 antagonist TG6-10-1 over a 2-3 day period accelerates functional recovery, attenuates hippocampal neurodegeneration, neuroinflammation, gliosis and blood-brain barrier leakage, and prevents long-term cognitive deficits without blocking SE itself or altering acute seizure characteristics. This work has provided important information regarding organophosphate-induced seizure related pathologies in adults and revealed the effectiveness of delayed EP2 inhibition to combat these pathologies.
Collapse
Affiliation(s)
- Asheebo Rojas
- Department of Pharmacology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, USA.
| | - Thota Ganesh
- Department of Pharmacology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, USA
| | - Wenyi Wang
- Department of Pharmacology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, USA
| | - Jennifer Wang
- Department of Pharmacology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, USA
| | - Raymond Dingledine
- Department of Pharmacology, Emory University, 1510 Clifton Road NE, Atlanta, GA 30322, USA
| |
Collapse
|
26
|
Impact of chronic low dose exposure of monocrotophos in rat brain: Oxidative/ nitrosative stress, neuronal changes and cholinesterase activity. Toxicol Rep 2019; 6:1295-1303. [PMID: 31867220 PMCID: PMC6906705 DOI: 10.1016/j.toxrep.2019.11.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 10/17/2019] [Accepted: 11/01/2019] [Indexed: 01/25/2023] Open
Abstract
Monocrotophos (MCP) is an organophosphate mainly used as insecticides in agriculture, and veterinary practice to control pests. Exposure to MCP is known to induce significant systemic toxicity in animals and humans. Short term exposure to a high dose of MCP has been reported to cause systemic toxicity, however limited information is available regarding low dose long term exposure in rats. We studied the effects of low dose long term exposure to MCP on oxidative/nitrosative stress, cholinesterase activity and neuronal loss in rat. Male rats were exposed to MCP (0.1 μg or 1 μg/ml) via drinking water for 8 weeks. The pro-oxidant markers such as reactive oxygen species (ROS), lipid peroxidation (MDA), nitrite level and antioxidant markers such as reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and inhibition of cholinesterase activities were measured to evaluate the effects of MCP on brain along with plasma cholinesterase activity. Neuronal loss was analyzed in cortical region using H&E stained slices. The results suggested that exposure to MC even at the low dose, increased reactive oxygen species, thiobarbituric acid reactive substance levels and decreased glutathione, superoxide dismutase, catalase and cholinesterase activities in brain. No significant effect however, was observed on nitrite levels. Histological analysis revealed that low dose MCP exposure lead to structural changes in the cortical neurons in rats. It can be concluded from the study that low dose long term exposure (lower than No Observed Effect Level) of MCP may lead to the generation of oxidative stress by elevation of pro-oxidants markers and depletion of antioxidant enzymes markers along with inhibition of cholinesterase activity. These changes might thus be considered as the possible mechanism of cortical neuronal loss in these animals.
Collapse
Key Words
- ATCI, acetylthiocholineiodide
- BSA, bovine serum albumin
- ChE, cholinesterase
- Cholinesterase inhibition
- DCFDA, 2, 7-dichlrofluorescein diacetate
- DMS, dimethyl sulfoxide
- DTNB, 5, 5-dithiobis (2-nitro-benzoic acid)
- H2O2, hydrogen peroxide
- MCP, monocrotophos
- MDA, malondialdehyde
- Monocrotophos
- NADH, nicotinamide adenine dinucleotide reduced
- NBT, nitrobluetetrazolium
- NO, nitric oxide
- NOEL, no observed effect level
- Na2CO3, sodium carbonate
- NaOH, sodium hydroxide
- Neuronal loss
- Nitrosative stress
- OP, organophosphate
- Oxidative stress
- PMSP, henazinemethosulphate
- ROS, reactive oxygen species
- Rat
- SDS, sodium dodecyl sulphate
- SOD, superoxide dismutase
- TBA, thiobarbituricacid
- TBARS, thiobarbituric acid reactive substances
- rGSH, reduced glutathion
Collapse
|
27
|
Yang J, Bruun DA, Wang C, Wan D, McReynolds CB, Phu K, Inceoglu B, Lein PJ, Hammock BD. Lipidomes of brain from rats acutely intoxicated with diisopropylfluorophosphate identifies potential therapeutic targets. Toxicol Appl Pharmacol 2019; 382:114749. [PMID: 31521729 PMCID: PMC6957308 DOI: 10.1016/j.taap.2019.114749] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 08/30/2019] [Accepted: 09/07/2019] [Indexed: 01/28/2023]
Abstract
Organophosphates (OPs), a class of phosphorus-containing chemicals that act by disrupting cholinergic transmission, include both toxic and fast-acting chemical warfare agents as well as less toxic but more easily accessible OP pesticides. The classical atropine/2-PAM antidote fails to protect against long-term symptoms following acute intoxication with OPs at levels that trigger status epilepticus. Acute OP intoxication also causes a robust neuroinflammatory response, which is implicated in the pathogenesis of long-term effects. In this study, we characterized the profiles of lipid mediators, important players in neuroinflammation, in the rat model of acute DFP intoxication. The profiles of lipid mediators were monitored in three different regions of the brain (cortex, hippocampus, and cerebellum) at 0, 1, 3, 7, 14, and 28 days post-exposure. The distribution pattern of lipid mediators was distinct in the three brain regions. In the cerebellum, the profile is dominated by LOX metabolites, while the lipid mediator profiles in cortex and hippocampus are dominated by COX metabolites followed by LOX and CYP 450 metabolites. Following acute DFP intoxication, most of the pro-inflammatory lipid mediators (e.g., PGD2 and PGE2) increased rapidly from day 1, while the concentrations of some anti-inflammatory lipid mediators (e.g. 14,15 EpETrE) decreased after DFP intoxication but recovered by day 14 post-exposure. The lipidomics results suggest two potential treatment targets: blocking the formation of prostaglandins by inhibiting COX and stabilizing the anti-inflammatory lipid mediators containing epoxides by inhibiting the enzyme soluble epoxide hydrolase (sEH).
Collapse
Affiliation(s)
- Jun Yang
- Department of Entomology and Nematology, and UCD Comprehensive Cancer Center, University of California, Davis, Davis, CA 95616, USA
| | - Donald A Bruun
- Department of Molecular Biosciences, University of California, Davis, CA 95616, USA
| | - Chang Wang
- Department of Entomology and Nematology, and UCD Comprehensive Cancer Center, University of California, Davis, Davis, CA 95616, USA; School of Radiation Medicine and Protection, Medical College of Soochow University, School for Radiological and Interdisciplinary Sciences (RAD-X), Jiangsu Provincial Key Laboratory of Radiation Medicine and Protection, Suzhou 215123, PR China
| | - Debin Wan
- Department of Entomology and Nematology, and UCD Comprehensive Cancer Center, University of California, Davis, Davis, CA 95616, USA
| | - Cindy B McReynolds
- Department of Entomology and Nematology, and UCD Comprehensive Cancer Center, University of California, Davis, Davis, CA 95616, USA
| | - Kenny Phu
- Department of Entomology and Nematology, and UCD Comprehensive Cancer Center, University of California, Davis, Davis, CA 95616, USA
| | - Bora Inceoglu
- Department of Entomology and Nematology, and UCD Comprehensive Cancer Center, University of California, Davis, Davis, CA 95616, USA
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California, Davis, CA 95616, USA
| | - Bruce D Hammock
- Department of Entomology and Nematology, and UCD Comprehensive Cancer Center, University of California, Davis, Davis, CA 95616, USA.
| |
Collapse
|
28
|
Pearson-Smith JN, Patel M. Antioxidant drug therapy as a neuroprotective countermeasure of nerve agent toxicity. Neurobiol Dis 2019; 133:104457. [PMID: 31028872 PMCID: PMC7721294 DOI: 10.1016/j.nbd.2019.04.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 04/18/2019] [Accepted: 04/23/2019] [Indexed: 12/12/2022] Open
Abstract
The use of chemical warfare agents is an ongoing, significant threat to both civilians and military personnel worldwide. Nerve agents are by far the most formidable toxicants in terms of their lethality and toxicity. Nerve agents initiate neurotoxicity by the irreversible inhibition of acetylcholinesterase and resultant accumulation of acetylcholine in excitable tissues. The cholinergic toxidrome presents as miosis, lacrimation, diarrhea, fasciculations, seizures, respiratory arrest and coma. Current medical countermeasures can attenuate acute mortality and confer limited protection against secondary neuronal injury when given rapidly after exposure. However, there is an urgent need for the development of novel, add-on neuroprotective therapies to prevent mortality and long-term toxicity of nerve agents. Increasing evidence suggests that pathways other than direct acetylcholinesterase inhibition contribute to neurotoxicity and secondary neuronal injury. Among these, oxidative stress is emerging as a key therapeutic target for nerve agent toxicity. In this review, we discuss the rationale for targeting oxidative stress in nerve agent toxicity and highlight research investigating antioxidant therapy as a neuroprotective medical countermeasure to attenuate oxidative stress, neuroinflammation and neurodegeneration.
Collapse
Affiliation(s)
- Jennifer N Pearson-Smith
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, 80045, United States of America
| | - Manisha Patel
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, 80045, United States of America.
| |
Collapse
|
29
|
Putra M, Sharma S, Gage M, Gasser G, Hinojo-Perez A, Olson A, Gregory-Flores A, Puttachary S, Wang C, Anantharam V, Thippeswamy T. Inducible nitric oxide synthase inhibitor, 1400W, mitigates DFP-induced long-term neurotoxicity in the rat model. Neurobiol Dis 2019; 133:104443. [PMID: 30940499 DOI: 10.1016/j.nbd.2019.03.031] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 02/22/2019] [Accepted: 03/28/2019] [Indexed: 11/26/2022] Open
Abstract
Chemical nerve agents (CNA) are increasingly becoming a threat to both civilians and military personnel. CNA-induced acute effects on the nervous system have been known for some time and the long-term consequences are beginning to emerge. In this study, we used diisopropylfluorophosphate (DFP), a seizurogenic CNA to investigate the long-term impact of its acute exposure on the brain and its mitigation by an inducible nitric oxide synthase (iNOS) inhibitor, 1400W as a neuroprotectant in the rat model. Several experimental studies have demonstrated that DFP-induced seizures and/or status epilepticus (SE) causes permanent brain injury, even after the countermeasure medication (atropine, oxime, and diazepam). In the present study, DFP-induced SE caused a significant increase in iNOS and 3-nitrotyrosine (3-NT) at 24 h, 48 h, 7d, and persisted for a long-term (12 weeks post-exposure), which led to the hypothesis that iNOS is a potential therapeutic target in DFP-induced brain injury. To test the hypothesis, we administered 1400W (20 mg/kg, i.m.) or the vehicle twice daily for the first three days of post-exposure. 1400W significantly reduced DFP-induced iNOS and 3-NT upregulation in the hippocampus and piriform cortex, and the serum nitrite levels at 24 h post-exposure. 1400W also prevented DFP-induced mortality in <24 h. The brain immunohistochemistry (IHC) at 7d post-exposure revealed a significant reduction in gliosis and neurodegeneration (NeuN+ FJB positive cells) in the 1400W-treated group. 1400W, in contrast to the vehicle, caused a significant reduction in the epileptiform spiking and spontaneous recurrent seizures (SRS) during 12 weeks of continuous video-EEG study. IHC of brain sections from the same animals revealed a significant reduction in reactive gliosis (both microgliosis and astrogliosis) and neurodegeneration across various brain regions in the 1400W-treated group when compared to the vehicle-treated group. A multiplex assay from hippocampal lysates at 6 weeks post-exposure showed a significant increase in several key pro-inflammatory cytokines/chemokines such as IL-1α, TNFα, IL-1β, IL-2, IL-6, IL-12, IL-17a, MCP-1, LIX, and Eotaxin, and a growth factor, VEGF in the vehicle-treated animals. 1400W significantly suppressed IL-1α, TNFα, IL-2, IL-12, and MCP-1 levels. It also suppressed DFP-induced serum nitrite levels at 6 weeks post-exposure. In the Morris water maze, the vehicle-treated animals spent significantly less time in the target quadrant in a probe trial at 9d post-exposure compared to their time spent in the same quadrant 11 days previously (i.e., 2 days prior to DFP exposure). Such a difference was not observed in the 1400W and control groups. However, learning and short-term memory were unaffected when tested at 10-16d and 28-34d post-exposure. Accelerated rotarod, horizontal bar test, and the forced swim test revealed no significant changes between groups. Overall, the findings from this study suggest that 1400W may be considered as a potential therapeutic agent as a follow-on therapy for CNA exposure, after controlling the acute symptoms, to prevent mortality and some of the long-term neurotoxicity parameters such as epileptiform spiking, SRS, neurodegeneration, reactive gliosis in some brain regions, and certain key proinflammatory cytokines and chemokine.
Collapse
Affiliation(s)
- Marson Putra
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, United States
| | - Shaunik Sharma
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, United States
| | - Meghan Gage
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, United States
| | | | - Andy Hinojo-Perez
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, United States
| | - Ashley Olson
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, United States
| | - Adriana Gregory-Flores
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, United States
| | - Sreekanth Puttachary
- Department of Biomedical Sciences, Carlson College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, United States
| | - Chong Wang
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, United States
| | | | - Thimmasettappa Thippeswamy
- Department of Biomedical Sciences, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, United States.
| |
Collapse
|
30
|
Deshpande LS, DeLorenzo RJ. Novel therapeutics for treating organophosphate-induced status epilepticus co-morbidities, based on changes in calcium homeostasis. Neurobiol Dis 2019; 133:104418. [PMID: 30872159 DOI: 10.1016/j.nbd.2019.03.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 02/26/2019] [Accepted: 03/09/2019] [Indexed: 11/24/2022] Open
Abstract
Organophosphate (OP) chemicals include pesticides such as parathion, and nerve gases such as sarin and soman and are considered major chemical threat agents. Acute OP exposure is associated with a cholinergic crisis and status epilepticus (SE). It is also known that the survivors of OP toxicity exhibit neurobehavioral deficits such as mood changes, depression, and memory impairment, and acquired epilepsy. Our research has focused on addressing the need to develop effective therapeutic agents that could be administered even after prolonged seizures and would prevent or lessen the chronic morbidity associated with OP-SE survival. We have developed rat survival models of OP pesticide metabolite paraoxon (POX) and nerve agent sarin surrogate diisopropyl fluorophosphate (DFP) induced SE that are being used to screen for medical countermeasures against an OP attack. Our research has focused on studying neuronal calcium (Ca2+) homeostatic mechanisms for identifying mechanisms and therapeutics for the expression of neurological morbidities associated with OP-SE survival. We have observed development of a "Ca2+ plateau" characterized by sustained elevations in neuronal Ca2+ levels in OP-SE surviving rats that coincided with the appearance of OP-SE chronic morbidities. These Ca2+ elevations had their origin in Ca2+ release from the intracellular stores such that blockade with antagonists like dantrolene, carisbamate, and levetiracetam lowered OP-SE mediated Ca2+ plateau and afforded significant neuroprotection. Since the Ca2+ plateau lasts for a prolonged period, our studies suggest that blocking it after the control of SE may represent a unique target for development of novel countermeasures to prevent long term Ca2+ mediated OP-SE neuropsychiatric comorbidities such as depression, anxiety, and acquired epilepsy (AE).
Collapse
Affiliation(s)
- Laxmikant S Deshpande
- Department of Neurology, Virginia Commonwealth University, Richmond, VA 23298, USA; Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Robert J DeLorenzo
- Department of Neurology, Virginia Commonwealth University, Richmond, VA 23298, USA; Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298, USA.
| |
Collapse
|
31
|
Bruun DA, Guignet M, Harvey DJ, Lein PJ. Pretreatment with pyridostigmine bromide has no effect on seizure behavior or 24 hour survival in the rat model of acute diisopropylfluorophosphate intoxication. Neurotoxicology 2019; 73:81-84. [PMID: 30853371 DOI: 10.1016/j.neuro.2019.03.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Revised: 02/27/2019] [Accepted: 03/04/2019] [Indexed: 01/16/2023]
Abstract
Acute intoxication with organophosphate cholinesterase inhibitors (OPs) is a significant human health threat, and current medical countermeasures for OP poisoning are of limited therapeutic efficacy. The rat model of acute intoxication with diisopropylfluorophosphate (DFP) is increasingly being used to test candidate compounds for efficacy in protecting against the immediate and long-term consequences of acute OP toxicity. In this model, rats are typically pretreated with pyridostigmine bromide (PB), a reversible cholinesterase inhibitor, to enhance survival. However, PB pretreatment is not likely in most scenarios of civilian exposure to acutely neurotoxic levels of OPs. Therefore, the goal of this study was to determine whether PB pretreatment significantly increases survival in DFP-intoxicated rats. Adult male Sprague Dawley rats were injected with DFP (4 mg/kg, s.c.) or vehicle (VEH) followed 1 min later by combined i.m. injection of atropine sulfate (2 mg/kg) and 2-pralidoxime (25 mg/kg). Animals were pretreated 30 min prior to these injections with PB (0.1 mg/kg, i.m.) or an equal volume of saline. DFP triggered rapid and sustained seizure behavior irrespective of PB pretreatment, and there was no significant difference in average seizure behavior score during the first 4 h following injection between DFP animals pretreated with PB or not. PB pretreatment also had no significant effect on survival or brain AChE activity at 24 h post-DFP exposure. In summary, PB pretreatment is not necessary to ensure survival of rats acutely intoxicated with DFP, and eliminating PB pretreatment in the rat model of acute DFP intoxication would increase its relevance to acute OP intoxication in civilians.
Collapse
Affiliation(s)
- Donald A Bruun
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA.
| | - Michelle Guignet
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA.
| | - Danielle J Harvey
- Department of Public Health Sciences, University of California-Davis, One Shields Avenue, Davis, CA, 95616, USA.
| | - Pamela J Lein
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA.
| |
Collapse
|
32
|
Jackson C, Ardinger C, Winter KM, McDonough JH, McCarren HS. Validating a model of benzodiazepine refractory nerve agent-induced status epilepticus by evaluating the anticonvulsant and neuroprotective effects of scopolamine, memantine, and phenobarbital. J Pharmacol Toxicol Methods 2019; 97:1-12. [PMID: 30790623 PMCID: PMC6529248 DOI: 10.1016/j.vascn.2019.02.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 02/05/2019] [Accepted: 02/14/2019] [Indexed: 12/26/2022]
Abstract
INTRODUCTION Organophosphorus nerve agents (OPNAs) irreversibly block acetylcholinesterase activity, resulting in accumulation of excess acetylcholine at neural synapses, which can lead to a state of prolonged seizures known as status epilepticus (SE). Benzodiazepines, the current standard of care for SE, become less effective as latency to treatment increases. In a mass civilian OPNA exposure, concurrent trauma and limited resources would likely cause a delay in first response time. To address this issue, we have developed a rat model to test novel anticonvulsant/ neuroprotectant adjuncts at delayed time points. METHODS For model development, adult male rats with cortical electroencephalographic (EEG) electrodes were exposed to soman and administered saline along with atropine, 2-PAM, and midazolam 5, 20, or 40 min after SE onset. We validated our model using three drugs: scopolamine, memantine, and phenobarbital. Using the same procedure outlined above, rats were given atropine, 2-PAM, midazolam and test treatment 20 min after SE onset. RESULTS Using gamma power, delta power, and spike rate to quantify EEG activity, we found that scopolamine was effective, memantine was minimally effective, and phenobarbital had a delayed effect on terminating SE. Fluoro-Jade B staining was used to assess neuroprotection in five brain regions. Each treatment provided significant protection compared to saline + midazolam in at least two brain regions. DISCUSSION Because our data agree with previously published studies on the efficacy of these compounds, we conclude that this model is a valid way to test novel anticonvulsants/ neuroprotectants for controlling benzodiazepine-resistant OPNA-induced SE and subsequent neuropathology.
Collapse
Affiliation(s)
| | | | | | | | - Hilary S. McCarren
- Corresponding author at: U.S. Army Medical Research Institute of Chemical Defense, 8350 Ricketts Point Road, Aberdeen Proving Ground, MD 21010, USA
| |
Collapse
|
33
|
Guignet M, Lein PJ. Neuroinflammation in organophosphate-induced neurotoxicity. ROLE OF INFLAMMATION IN ENVIRONMENTAL NEUROTOXICITY 2019. [DOI: 10.1016/bs.ant.2018.10.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|
34
|
Chaubey K, Alam SI, Waghmare CK, Singh L, Srivastava N, Bhattacharya BK. Differential proteome analysis of rat plasma after diisopropyl fluorophosphate (DFP) intoxication, a surrogate of nerve agent sarin. Chem Biol Interact 2018; 298:66-71. [PMID: 30389396 DOI: 10.1016/j.cbi.2018.10.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 10/22/2018] [Accepted: 10/26/2018] [Indexed: 01/06/2023]
Abstract
Diisopropyl fluorophosphate (DFP), a surrogate of nerve agent sarin, is an organophosphorus (OP) compound which inhibits neuronal enzyme acetylcholinesterase (AChE). Exposure of this compound leads to a wide range of toxic symptoms and survivors may exhibit long term neurotoxicity related to cognitive and memory defects. Due to ease of availability and similar mechanism of action to other highly toxic nerve agent, DFP is widely used as model compound to trace changes associated with nerve agent exposures. Proximal fluids are widely used for the elucidation of biomarkers for exposure to toxic substances and to study the mechanism of toxicity. Using a rat model of OP intoxication, the present study was carried out to elucidate proteomic changes in plasma associated with DFP intoxication. Rats were exposed to a single dose (0.5 LD50) of DFP and their plasma proteome was studied, one day post exposure by two dimensional gel electrophoresis - mass spectrometry (2DE-MS). Some of the milestone changes were validated by Western blot analysis. A total 15 proteins showed significant fold changes in expression with respect to control after 1 day of DFP intoxication. Most of the proteins showing changes in expression at initial stages were related to immunogenic function, acute phase response, blood coagulation, and stress response. Experiments reported here demonstrate that 0.5 LD50 DFP intoxication leads to AChE inhibition, modulation of immunogenic function, and generation of stress at an early stage. Although, some proteins and their putative functional ramifications indicated similarity with those observed in our previous plasma proteome study, neurodegenerative changes were not observed in plasma of 0.5 LD50 DFP treated animals.
Collapse
Affiliation(s)
- Kalyani Chaubey
- Defence Research & Development Establishment (DRDE), Jhansi Road, Gwalior, MP, 474002, India
| | - Syed Imteyaz Alam
- Defence Research & Development Establishment (DRDE), Jhansi Road, Gwalior, MP, 474002, India.
| | - Chandra Kant Waghmare
- Defence Research & Development Establishment (DRDE), Jhansi Road, Gwalior, MP, 474002, India
| | - Lokendra Singh
- Defence Research & Development Establishment (DRDE), Jhansi Road, Gwalior, MP, 474002, India
| | - Nalini Srivastava
- School of Studies in Biochemistry, Jiwaji University, Gwalior, MP, 474002, India
| | - Bijoy K Bhattacharya
- Defence Research & Development Establishment (DRDE), Jhansi Road, Gwalior, MP, 474002, India.
| |
Collapse
|
35
|
Kuruba R, Wu X, Reddy DS. Benzodiazepine-refractory status epilepticus, neuroinflammation, and interneuron neurodegeneration after acute organophosphate intoxication. Biochim Biophys Acta Mol Basis Dis 2018; 1864:2845-2858. [PMID: 29802961 PMCID: PMC6066461 DOI: 10.1016/j.bbadis.2018.05.016] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 04/30/2018] [Accepted: 05/22/2018] [Indexed: 12/19/2022]
Abstract
Nerve agents and some pesticides such as diisopropylfluorophosphate (DFP) cause neurotoxic manifestations that include seizures and status epilepticus (SE), which are potentially lethal and carry long-term neurological morbidity. Current antidotes for organophosphate (OP) intoxication include atropine, 2-PAM and diazepam (a benzodiazepine for treating seizures and SE). There is some evidence for partial or complete loss of diazepam anticonvulsant efficacy when given 30 min or later after exposure to an OP; this condition is known as refractory SE. Effective therapies for OP-induced SE are lacking and it is unclear why current therapies do not work. In this study, we investigated the time-dependent efficacy of diazepam in the nerve agent surrogate DFP model of OP intoxication on seizure suppression and neuroprotection in rats, following an early and late therapy. Diazepam (5 mg/kg, IM) controlled seizures when given 10 min after DFP exposure ("early"), but it was completely ineffective at 60 or 120 min ("late") after DFP. DFP-induced neuronal injury, neuroinflammation, and neurodegeneration of principal cells and GABAergic interneurons were significantly reduced by early but not late therapy. These findings demonstrate that diazepam failed to control seizures, SE and neuronal injury when given 60 min or later after DFP exposure, confirming the benzodiazepine-refractory SE and brain damage after OP intoxication. In addition, this study indicates that degeneration of inhibitory interneurons and inflammatory glial activation are potential mechanisms underlying these morbid outcomes of OP intoxication. Therefore, novel anticonvulsant and neuroprotectant antidotes, superior to benzodiazepines, are desperately needed for controlling nerve agent-induced SE and brain injury.
Collapse
Affiliation(s)
- Ramkumar Kuruba
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, College of Medicine, Bryan, TX 77807, USA
| | - Xin Wu
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, College of Medicine, Bryan, TX 77807, USA
| | - Doodipala Samba Reddy
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, College of Medicine, Bryan, TX 77807, USA.
| |
Collapse
|
36
|
Wu X, Kuruba R, Reddy DS. Midazolam-Resistant Seizures and Brain Injury after Acute Intoxication of Diisopropylfluorophosphate, an Organophosphate Pesticide and Surrogate for Nerve Agents. J Pharmacol Exp Ther 2018; 367:302-321. [PMID: 30115757 DOI: 10.1124/jpet.117.247106] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 08/14/2018] [Indexed: 12/15/2022] Open
Abstract
Organophosphates (OP) such as the pesticide diisopropylfluorophosphate (DFP) and the nerve agent sarin are lethal chemicals that induce seizures, status epilepticus (SE), and brain damage. Midazolam, a benzodiazepine modulator of synaptic GABA-A receptors, is currently considered as a new anticonvulsant for nerve agents. Here, we characterized the time course of protective efficacy of midazolam (0.2-5 mg/kg, i.m.) in rats exposed to DFP, a chemical threat agent and surrogate for nerve agents. Behavioral and electroencephalogram (EEG) seizures were monitored for 24 hours after DFP exposure. The extent of brain injury was determined 3 days after DFP exposure by unbiased stereologic analyses of valid markers of neurodegeneration and neuroinflammation. Seizures were elicited within ∼8 minutes after DFP exposure that progressively developed into persistent SE lasting for hours. DFP exposure resulted in massive neuronal injury or necrosis, neurodegeneration of principal cells and interneurons, and neuroinflammation as evident by extensive activation of microglia and astrocytes in the hippocampus, amygdala, and other brain regions. Midazolam controlled seizures, neurodegeneration, and neuroinflammation when given early (10 minutes) after DFP exposure, but it was less effective when given at 40 minutes or later. Delayed therapy (≥40 minutes), a simulation of the practical therapeutic window for first responders or hospital admission, was associated with reduced seizure protection and neuroprotection. These results strongly reaffirm that the DFP-induced seizures and brain damage are progressively resistant to delayed treatment with midazolam, confirming the benzodiazepine refractory SE after OP intoxication. Thus, novel anticonvulsants superior to midazolam or adjunct therapies that enhance its efficacy are needed for effective treatment of refractory SE.
Collapse
Affiliation(s)
- Xin Wu
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center College of Medicine, Bryan, Texas
| | - Ramkumar Kuruba
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center College of Medicine, Bryan, Texas
| | - Doodipala Samba Reddy
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center College of Medicine, Bryan, Texas
| |
Collapse
|
37
|
Surles-Zeigler MC, Li Y, Distel TJ, Omotayo H, Ge S, Ford BD. Transcriptomic analysis of neuregulin-1 regulated genes following ischemic stroke by computational identification of promoter binding sites: A role for the ETS-1 transcription factor. PLoS One 2018; 13:e0197092. [PMID: 29856744 PMCID: PMC5983438 DOI: 10.1371/journal.pone.0197092] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 04/26/2018] [Indexed: 11/19/2022] Open
Abstract
Ischemic stroke is a major cause of mortality in the United States. We previously showed that neuregulin-1 (NRG1) was neuroprotective in rat models of ischemic stroke. We used gene expression profiling to understand the early cellular and molecular mechanisms of NRG1's effects after the induction of ischemia. Ischemic stroke was induced by middle cerebral artery occlusion (MCAO). Rats were allocated to 3 groups: (1) control, (2) MCAO and (3) MCAO + NRG1. Cortical brain tissues were collected three hours following MCAO and NRG1 treatment and subjected to microarray analysis. Data and statistical analyses were performed using R/Bioconductor platform alongside Genesis, Ingenuity Pathway Analysis and Enrichr software packages. There were 2693 genes differentially regulated following ischemia and NRG1 treatment. These genes were organized by expression patterns into clusters using a K-means clustering algorithm. We further analyzed genes in clusters where ischemia altered gene expression, which was reversed by NRG1 (clusters 4 and 10). NRG1, IRS1, OPA3, and POU6F1 were central linking (node) genes in cluster 4. Conserved Transcription Factor Binding Site Finder (CONFAC) identified ETS-1 as a potential transcriptional regulator of NRG1 suppressed genes following ischemia. A transcription factor activity array showed that ETS-1 activity was increased 2-fold, 3 hours following ischemia and this activity was attenuated by NRG1. These findings reveal key early transcriptional mechanisms associated with neuroprotection by NRG1 in the ischemic penumbra.
Collapse
Affiliation(s)
- Monique C. Surles-Zeigler
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, Georgia, United States of America
| | - Yonggang Li
- Department of Biomedical Sciences, University of California–Riverside School of Medicine, Riverside, California, United States of America
- ICF, Atlanta, GA, United States of America
| | - Timothy J. Distel
- Department of Biomedical Sciences, University of California–Riverside School of Medicine, Riverside, California, United States of America
| | - Hakeem Omotayo
- Department of Biomedical Sciences, University of California–Riverside School of Medicine, Riverside, California, United States of America
| | - Shaokui Ge
- Department of Biomedical Sciences, University of California–Riverside School of Medicine, Riverside, California, United States of America
| | - Byron D. Ford
- Department of Biomedical Sciences, University of California–Riverside School of Medicine, Riverside, California, United States of America
- * E-mail:
| |
Collapse
|
38
|
Scholl EA, Miller-Smith SM, Bealer SL, Lehmkuhle MJ, Ekstrand JJ, Dudek FE, McDonough JH. Age-dependent behaviors, seizure severity and neuronal damage in response to nerve agents or the organophosphate DFP in immature and adult rats. Neurotoxicology 2018; 66:10-21. [PMID: 29510177 PMCID: PMC5996394 DOI: 10.1016/j.neuro.2018.02.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 02/07/2018] [Accepted: 02/27/2018] [Indexed: 01/15/2023]
Abstract
Exposure to nerve agents (NAs) and other organophosphates (OPs) can initiate seizures that rapidly progress to status epilepticus (SE). While the electrographic and neuropathological sequelae of SE evoked by NAs and OPs have been characterized in adult rodents, they have not been adequately investigated in immature animals. In this study postnatal day (PND) 14, 21 and 28 rat pups, along with PND70 animals as adult controls, were exposed to NAs (sarin, VX) or another OP (diisopropylfluorophosphate, DFP). We then evaluated behavioral and electrographic (EEG) correlates of seizure activity, and performed neuropathology using Fluoro-Jade B. Although all immature rats exhibited behaviors that are often characterized as seizures, the incidence, duration, and severity of the electrographic seizure activity were age-dependent. No (sarin and VX) or brief (DFP) EEG seizure activity was evoked in PND14 rats, while SE progressively increased in severity as a function of age in PND21, 28 and 70 animals. Fluoro-Jade B staining was observed in multiple brain regions of animals that exhibited prolonged seizure activity. Neuronal injury in PND14 animals treated with DFP was lower than in older animals and absent in rats exposed to sarin or VX. In conclusion, we found that NAs and an OP provoked robust SE and neuronal injury similar to adults in PND21 and PND28, but not in PND14, rat pups. Convulsive behaviors were often present independent of EEG seizures and were unaccompanied by neuronal damage. These differential responses should be considered when investigating medical countermeasures for NA and OP exposure in pediatric populations.
Collapse
Affiliation(s)
- Erika A Scholl
- Department of Neurosurgery, University of Utah, Salt Lake City, UT, 84108 USA
| | - Stephanie M Miller-Smith
- Neuroscience Branch, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, 21010-5400 USA
| | - Steven L Bealer
- Department of Neurosurgery, University of Utah, Salt Lake City, UT, 84108 USA; Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT, 84108 USA
| | - Mark J Lehmkuhle
- Department of Neurosurgery, University of Utah, Salt Lake City, UT, 84108 USA; Epitel, Inc., Salt Lake City, UT, 84111 USA
| | - Jeffrey J Ekstrand
- Department of Pediatrics, University of Utah, Salt Lake City, UT, 84108 USA
| | - F Edward Dudek
- Department of Neurosurgery, University of Utah, Salt Lake City, UT, 84108 USA
| | - John H McDonough
- Neuroscience Branch, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD, 21010-5400 USA.
| |
Collapse
|
39
|
Sisó S, Hobson BA, Harvey DJ, Bruun DA, Rowland DJ, Garbow JR, Lein PJ. Editor's Highlight: Spatiotemporal Progression and Remission of Lesions in the Rat Brain Following Acute Intoxication With Diisopropylfluorophosphate. Toxicol Sci 2018; 157:330-341. [PMID: 28329845 DOI: 10.1093/toxsci/kfx048] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Similar to organophosphate (OP) nerve agents, diisopropylfluorophosphate (DFP) rapidly and irreversibly inhibits acetylcholinesterase, leading to convulsions that can progress to status epilepticus (SE). However, in contrast to the OP nerve agents, the long-term consequences of DFP-induced SE are not well known. Thus, we characterized the spatiotemporal profile of neuropathology during the first 2 months following acute DFP intoxication. Adult, male Sprague Dawley rats administered pyridostigmine bromide (0.1 mg/kg, im) 30 min prior to successive administration of DFP (4 mg/kg, sc), atropine sulfate (2 mg/kg, im), and 2-pralidoxime (25 mg/kg, im), exhibited moderate-to-severe seizure behavior, yet survived until euthanized at 0.5 to 60 days post exposure. Analyses of brains and hearts stained with hematoxylin-eosin, or of brains immunostained for neuronal nuclei (NeuN), glial fibrillary acidic protein (GFAP), or ionized binding adapter molecule 1 (IBA1), revealed progressive neuronal cell death, neuroinflammation, and tissue remodeling across limbic brain regions and the cerebral cortex, with no detectable pathology in the cerebellum or the heart. The lesion type and progression varied according to brain region and time after exposure. Across multiple brain regions, neuronal necrosis peaked after the first week, and neuroinflammation persisted at least 2 months after intoxication. Notably, mineralization was observed at later times in the thalamus, and to a more limited extent, in the hippocampus. Lesion severity was influenced by the initial seizure severity, and spontaneous recurrent seizures were associated with more severe brain damage. These findings parallel descriptions of neuropathology in preclinical models of acute intoxication with OP nerve agents, and other seizurogenic chemicals, suggesting conserved mechanisms of pathology downstream of chemical-induced SE.
Collapse
Affiliation(s)
- Sílvia Sisó
- Translational Biology in the Department of Research, BioMarin Pharmaceuticals Inc, Novato, California, USA
| | - Brad A Hobson
- Department of Molecular Biosciences School of Veterinary Medicine, University of California-Davis, Davis, California, USA
| | - Danielle J Harvey
- Department of Public Health Sciences School of Medicine, University of California-Davis, Davis, California, USA
| | - Donald A Bruun
- Department of Molecular Biosciences School of Veterinary Medicine, University of California-Davis, Davis, California, USA
| | - Douglas J Rowland
- Department of Biomedical Engineering and the Center for Molecular and Genomic Imaging College of Engineering, University of California-Davis, Davis, California, USA
| | - Joel R Garbow
- Biomedical Magnetic Resonance Laboratory, Mallinckrodt Institute of Radiology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Pamela J Lein
- Department of Molecular Biosciences School of Veterinary Medicine, University of California-Davis, Davis, California, USA
| |
Collapse
|
40
|
Rojas A, Wang W, Glover A, Manji Z, Fu Y, Dingledine R. Beneficial Outcome of Urethane Treatment Following Status Epilepticus in a Rat Organophosphorus Toxicity Model. eNeuro 2018; 5:ENEURO.0070-18.2018. [PMID: 29766039 PMCID: PMC5952304 DOI: 10.1523/eneuro.0070-18.2018] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 03/21/2018] [Accepted: 03/22/2018] [Indexed: 01/07/2023] Open
Abstract
The efficacy of benzodiazepines to terminate electrographic status epilepticus (SE) declines the longer a patient is in SE. Therefore, alternative methods for ensuring complete block of SE and refractory SE are necessary. We compared the ability of diazepam and a subanesthetic dose of urethane to terminate prolonged SE and mitigate subsequent pathologies. Adult Sprague Dawley rats were injected with diisopropylfluorophosphate (DFP) to induce SE. Rats were administered diazepam (10 mg/kg, ip) or urethane (0.8 g/kg, s.c.) 1 h after DFP-induced SE and compared to rats that experienced uninterrupted SE. Large-amplitude and high-frequency spikes induced by DFP administration were quenched for at least 46 h in rats administered urethane 1 h after SE onset as demonstrated by cortical electroencephalography (EEG). By contrast, diazepam interrupted SE but seizures with high power in the 20- to 70-Hz band returned 6-10 h later. Urethane was more effective than diazepam at reducing hippocampal neurodegeneration, brain inflammation, gliosis and weight loss as measured on day 4 after SE. Furthermore, rats administered urethane displayed a 73% reduction in the incidence of spontaneous recurrent seizures after four to eight weeks and a 90% reduction in frequency of seizures in epileptic rats. By contrast, behavioral changes in the light/dark box, open field and a novel object recognition task were not improved by urethane. These findings indicate that in typical rodent SE models, it is the return of SE overnight, and not the initially intense 1-2 h of SE experience, that is largely responsible for neurodegeneration, accompanying inflammation, and the subsequent development of epilepsy.
Collapse
Affiliation(s)
- Asheebo Rojas
- Department of Pharmacology, Emory University, Atlanta, GA 30322
| | - Wenyi Wang
- Department of Pharmacology, Emory University, Atlanta, GA 30322
| | - Avery Glover
- Department of Pharmacology, Emory University, Atlanta, GA 30322
| | - Zahra Manji
- Department of Pharmacology, Emory University, Atlanta, GA 30322
| | - Yujiao Fu
- Department of Pharmacology, Emory University, Atlanta, GA 30322
| | | |
Collapse
|
41
|
McCarren HS, Arbutus JA, Ardinger C, Dunn EN, Jackson CE, McDonough JH. Dexmedetomidine stops benzodiazepine-refractory nerve agent-induced status epilepticus. Epilepsy Res 2018; 141:1-12. [PMID: 29414381 DOI: 10.1016/j.eplepsyres.2018.01.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 12/21/2017] [Accepted: 01/07/2018] [Indexed: 12/15/2022]
Abstract
Nerve agents are highly toxic chemicals that pose an imminent threat to soldiers and civilians alike. Nerve agent exposure leads to an increase in acetylcholine within the central nervous system, resulting in development of protracted seizures known as status epilepticus (SE). Currently, benzodiazepines are the standard of care for nerve agent-induced SE, but their efficacy quickly wanes as the time to treatment increases. Here, we examine the role of the α2-adrenoceptor in termination of nerve agent-induced SE using the highly specific agonist dexmedetomidine (DEX). Adult male rats were exposed to soman and entered SE as confirmed by electroencephalograph (EEG). We observed that administration of DEX in combination with the benzodiazepine midazolam (MDZ) 20 or 40 min after the onset of SE stopped seizures and returned processed EEG measurements to baseline levels. The protective effect of DEX was blocked by the α2-adrenoceptor antagonist atipamezole (ATI), but ATI failed to restore seizure activity after it was already halted by DEX in most cases, suggesting that α2-adrenoceptors may be involved in initiating SE cessation rather than merely suppressing seizure activity. Histologically, treatment with DEX + MDZ significantly reduced the number of dying neurons as measured by FluoroJade B in the amygdala, thalamus, and piriform cortex, but did not protect the hippocampus or parietal cortex even when SE was successfully halted. We conclude that DEX serves not just as a valuable potential addition to the anticonvulsant regimen for nerve agent exposure, but also as a tool for dissecting the neural circuitry that drives SE.
Collapse
Affiliation(s)
- Hilary S McCarren
- USAMRICD, Medical Toxicology Research Division, Neuroscience Branch, 2900 Ricketts Point Rd, Aberdeen Proving Ground, MD 21010, United States.
| | - Julia A Arbutus
- USAMRICD, Medical Toxicology Research Division, Neuroscience Branch, 2900 Ricketts Point Rd, Aberdeen Proving Ground, MD 21010, United States
| | - Cherish Ardinger
- USAMRICD, Medical Toxicology Research Division, Neuroscience Branch, 2900 Ricketts Point Rd, Aberdeen Proving Ground, MD 21010, United States
| | - Emily N Dunn
- USAMRICD, Medical Toxicology Research Division, Neuroscience Branch, 2900 Ricketts Point Rd, Aberdeen Proving Ground, MD 21010, United States
| | - Cecelia E Jackson
- USAMRICD, Medical Toxicology Research Division, Neuroscience Branch, 2900 Ricketts Point Rd, Aberdeen Proving Ground, MD 21010, United States
| | - John H McDonough
- USAMRICD, Medical Toxicology Research Division, Neuroscience Branch, 2900 Ricketts Point Rd, Aberdeen Proving Ground, MD 21010, United States
| |
Collapse
|
42
|
Effect of vitamins B 1, B 6, and B 12 (Neurobion) on Diisopropylfluorophosphate-induced Delayed Neuropathy in Mice. IRANIAN JOURNAL OF PHARMACEUTICAL RESEARCH : IJPR 2018; 17:1116-1124. [PMID: 30127834 PMCID: PMC6094411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Certain organophosphorus esters, such as diisopropylfluorophosphate (DFP), cause delayed neuropathy by inhibition of neuropathy target esterase (NTE) keeping the neuron in normal function. In this study, effects of neurobion alone and in combination with dexamethasone on DFP-induced delayed neuropathy were evaluated. Thirty-five mice were divided into five groups, each consisting of 7 mice. Except group1 (Normal group), group 2 received normal saline and 1h later, 1 mg/kg DFP; groups 3, 4 and 5 received 150 mg/kg neurobion, 2 mg/kg dexamethasone and 150 mg/kg neurobion plus 2 mg/kg dexamethasone, respectively and 1h later 1mg/kg DFP. Twenty one days after the last injection, the mice were killed by decapitation under deep anesthesia. NTE level was determined in the brain and though there was no significant difference between the groups, neurobion and neurobion plus dexamethasone partly- not significantly (p > 0.05)- were able to prevent reduction of NTE in the brain caused by DFP. Histopathological evaluation of sciatic nerves showed that neurobion and neurobion plus dexamethasone significantly suppressed the harmful effect of DFP. We also evaluated the activity of acetylcholine esterase (AChE), concentration of glutathione (GSH), and malondialdehyde (MDA) levels in the serum. Results showed dexamethasone (p < 0.001) and dexamethasone in combination with neurobion (p < 0.01) diminished AChE activity significantly compared to the DFP group. Neurobion caused a significant increase in the GSH level (p < 0.05). No significant change was seen in MDA. It is suggested that neurobion should be added and used in the first aid equipment and techniques for exposure to organophosphorus compounds, e.g. pesticides and chemical warfare.
Collapse
|
43
|
Hobson BA, Rowland DJ, Supasai S, Harvey DJ, Lein PJ, Garbow JR. A magnetic resonance imaging study of early brain injury in a rat model of acute DFP intoxication. Neurotoxicology 2017; 66:170-178. [PMID: 29183789 DOI: 10.1016/j.neuro.2017.11.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 11/21/2017] [Accepted: 11/24/2017] [Indexed: 11/18/2022]
Abstract
Current treatments for seizures induced by organophosphates do not protect sufficiently against progressive neurodegeneration or delayed cognitive impairment. Developing more effective therapeutic approaches has been challenging because the pathogenesis of these delayed consequences is poorly defined. Using magnetic resonance imaging (MRI), we previously reported brain lesions that persist for months in a rat model of acute intoxication with the OP, diisopropylfluorophosphate (DFP). However, the early spatiotemporal progression of these lesions remains unknown. To address this data gap, we used in vivo MRI to longitudinally monitor brain lesions during the first 3 d following acute DFP intoxication. Adult male Sprague Dawley rats acutely intoxicated with DFP (4mg/kg, sc) were MR imaged at 6, 12, 18, 24, 48, 72h post-DFP, and their brains then taken for correlative histology to assess neurodegeneration using FluoroJade C (FJC) staining. Acute DFP intoxication elicited moderate-to-severe seizure activity. T2-weighted (T2w) anatomic imaging revealed prominent lesions within the thalamus, piriform cortex, cerebral cortex, hippocampus, corpus striatum, and substantia nigra that corresponded to neurodegeneration, evident as bands of FJC positive cells. Semi-quantitative assessment of lesion severity demonstrated significant regional variation in the onset and progression of injury, and suggested that lesion severity may be modulated by isoflurane anesthesia. These results imply that the timing of therapeutic intervention for attenuating brain injury following OP intoxication may be regionally dependent, and that longitudinal assessment of OP-induced damage by MRI may be a powerful tool for assessing therapeutic response.
Collapse
Affiliation(s)
- Brad A Hobson
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, United States.
| | - Douglas J Rowland
- Center for Molecular and Genomic Imaging, University of California, Davis, College of Engineering, Davis, CA, 95616, United States.
| | - Suangsuda Supasai
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, United States.
| | - Danielle J Harvey
- Department of Public Health Sciences, University of California, Davis, School of Medicine, Davis, CA, 95616, United States.
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA, 95616, United States.
| | - Joel R Garbow
- Biomedical Magnetic Resonance Laboratory, Mallinckrodt Institute of Radiology, School of Medicine,Washington University in St. Louis, St. Louis, MO, 63110, United States.
| |
Collapse
|
44
|
Zhang T, Todorovic MS, Williamson J, Kapur J. Flupirtine and diazepam combination terminates established status epilepticus: results in three rodent models. Ann Clin Transl Neurol 2017; 4:888-896. [PMID: 29296617 PMCID: PMC5740237 DOI: 10.1002/acn3.497] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 09/30/2017] [Accepted: 10/09/2017] [Indexed: 12/17/2022] Open
Abstract
Objective Status epilepticus (SE) is a neurological emergency requiring rapid termination of seizures. New treatment choices are needed for benzodiazepine-refractory SE or established SE (ESE). Previous studies have demonstrated that the potassium-channel opener flupirtine terminates seizures in neonatal animals. However, its effectiveness in adult ESE has not been tested. We tested whether flupirtine alone or in combination with the benzodiazepine diazepam would terminate ESE in three animal models. Methods SE was induced by administration of lithium followed by pilocarpine, by electrical stimulation of the hippocampus or by diisopropylfluorophosphate (DFP) administration. Seizures were assessed by EEG recorded from the hippocampus and cortex. Results Flupirtine alone did not terminate ESE within 60 min of administration in any of the three models of ESE. A combination of flupirtine and diazepam terminated ESE within 60 min in all the three models. The drug combination shortened the duration of ESE in all three models. Drug responsiveness was distinct between each model. Conclusion A combination of the potassium channel opener flupirtine and diazepam is a potential therapy for ESE.
Collapse
Affiliation(s)
- Terry Zhang
- Department of Neurology University of Virginia Health Sciences Center Charlottesville Virginia 22908
| | - Marko S Todorovic
- Department of Neurology University of Virginia Health Sciences Center Charlottesville Virginia 22908
| | - John Williamson
- Department of Neurology University of Virginia Health Sciences Center Charlottesville Virginia 22908
| | - Jaideep Kapur
- Department of Neurology University of Virginia Health Sciences Center Charlottesville Virginia 22908.,Department of Neuroscience University of Virginia Health Sciences Center Charlottesville Virginia 22908
| |
Collapse
|
45
|
Locker AR, Michalovicz LT, Kelly KA, Miller JV, Miller DB, O'Callaghan JP. Corticosterone primes the neuroinflammatory response to Gulf War Illness-relevant organophosphates independently of acetylcholinesterase inhibition. J Neurochem 2017; 142:444-455. [PMID: 28500787 PMCID: PMC5575502 DOI: 10.1111/jnc.14071] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 04/29/2017] [Accepted: 05/08/2017] [Indexed: 12/16/2022]
Abstract
Gulf War Illness (GWI) is a chronic multi-symptom disorder affecting veterans of the 1991 Gulf War. Among the symptoms of GWI are those associated with sickness behavior, observations suggestive of underlying neuroinflammation. We have shown that exposure of mice to the stress hormone, corticosterone (CORT), and to diisopropyl fluorophosphate (DFP), as a nerve agent mimic, results in marked neuroinflammation, findings consistent with a stress/neuroimmune basis of GWI. Here, we examined the contribution of irreversible and reversible acetylcholinesterase (AChE) inhibitors to neuroinflammation in our mouse model of GWI. Male C57BL/6J mice received 4 days of CORT (400 mg/L) in the drinking water followed by a single dose of chlorpyrifos oxon (CPO; 8 mg/kg, i.p.), DFP (4 mg/kg, i.p.), pyridostigmine bromide (PB; 3 mg/kg, i.p.), or physostigmine (PHY; 0.5 mg/kg, i.p.). CPO and DFP alone caused cortical and hippocampal neuroinflammation assessed by qPCR of tumor necrosis factor-alpha, IL-6, C-C chemokine ligand 2, IL-1β, leukemia inhibitory factor and oncostatin M; CORT pretreatment markedly augmented these effects. Additionally, CORT exposure prior to DFP or CPO enhanced activation of the neuroinflammation signal transducer, signal transducer and activator of transcription 3 (STAT3). In contrast, PHY or PB alone or with CORT pretreatment did not produce neuroinflammation or STAT3 activation. While all of the CNS-acting AChE inhibitors (DFP, CPO, and PHY) decreased brain AChE activity, CORT pretreatment abrogated these effects for the irreversible inhibitors. Taken together, these findings suggest that irreversible AChE inhibitor-induced neuroinflammation and particularly its exacerbation by CORT, result from non-cholinergic effects of these compounds, pointing potentially to organophosphorylation of other neuroimmune targets.
Collapse
Affiliation(s)
- Alicia R. Locker
- Health Effects Laboratory DivisionCenters for Disease Control and PreventionNational Institute for Occupational Safety and HealthMorgantownWest VirginiaUSA
| | - Lindsay T. Michalovicz
- Health Effects Laboratory DivisionCenters for Disease Control and PreventionNational Institute for Occupational Safety and HealthMorgantownWest VirginiaUSA
| | - Kimberly A. Kelly
- Health Effects Laboratory DivisionCenters for Disease Control and PreventionNational Institute for Occupational Safety and HealthMorgantownWest VirginiaUSA
| | - Julie V. Miller
- Health Effects Laboratory DivisionCenters for Disease Control and PreventionNational Institute for Occupational Safety and HealthMorgantownWest VirginiaUSA
| | - Diane B. Miller
- Health Effects Laboratory DivisionCenters for Disease Control and PreventionNational Institute for Occupational Safety and HealthMorgantownWest VirginiaUSA
| | - James P. O'Callaghan
- Health Effects Laboratory DivisionCenters for Disease Control and PreventionNational Institute for Occupational Safety and HealthMorgantownWest VirginiaUSA
| |
Collapse
|
46
|
Hobson BA, Sisó S, Rowland DJ, Harvey DJ, Bruun DA, Garbow JR, Lein PJ. From the Cover: MagneticResonance Imaging Reveals Progressive Brain Injury in Rats Acutely Intoxicated With Diisopropylfluorophosphate. Toxicol Sci 2017; 157:342-353. [PMID: 28329842 PMCID: PMC5458789 DOI: 10.1093/toxsci/kfx049] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Acute intoxication with organophosphates (OPs) can trigger seizures that progress to status epilepticus, and survivors often exhibit chronic neuropathology, cognitive impairment, affective disorders, and/or electroencephalographic abnormalities. Understanding how acute injury transitions to persistent neurological sequelae is critical to developing medical countermeasures for mitigating damage following OP-induced seizures. Here, we used in vivo magnetic resonance imaging (MRI) to monitor the spatiotemporal patterns of neuropathology for 1 month after acute intoxication with diisopropylfluorophosphate (DFP). Adult male Sprague Dawley rats administered pyridostigmine bromide (0.1 mg/kg, im) 30 min prior to successive administration of DFP (4 mg/kg, sc), atropine sulfate (2 mg/kg, im), and 2-pralidoxime (25 mg/kg, im) exhibited moderate-to-severe seizure behavior. T2-weighted and diffusion-weighted MR imaging prior to DFP exposure and at 3, 7, 14, 21, or 28 days postexposure revealed prominent lesions, tissue atrophy, and ventricular enlargement in discrete brain regions. Lesions varied in intensity and/or extent over time, with the overall magnitude of injury strongly influenced by seizure severity. Importantly, lesions detected by MRI correlated spatially and temporally with histological evidence of brain pathology. Analysis of histogram parameters extracted from frequency distributions of regional apparent diffusion coefficient (ADC) values identified the standard deviation and 90th percentile of the ADC as robust metrics for quantifying persistent and progressive neuropathological changes. The interanimal and interregional variations observed in lesion severity and progression, coupled with potential reinjury following spontaneous recurrent seizures, underscore the advantages of using in vivo imaging to longitudinally monitor neuropathology and, ultimately, therapeutic response, following acute OP intoxication.
Collapse
Affiliation(s)
- Brad A. Hobson
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, Davis, California 95616
| | - Sílvia Sisó
- Translational Biology in the Department of Research, BioMarin Pharmaceuticals Inc, Novato, California 94949
| | - Douglas J. Rowland
- Department of Biomedical Engineering and the Center for Molecular and Genomic Imaging College of Engineering
| | - Danielle J. Harvey
- Department of Public Health Sciences School of Medicine, University of California-Davis, Davis, California 95616
| | - Donald A. Bruun
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, Davis, California 95616
| | - Joel R. Garbow
- Biomedical Magnetic Resonance Laboratory, Mallinckrodt Institute of Radiology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri 63110
| | - Pamela J. Lein
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, Davis, California 95616
| |
Collapse
|
47
|
Rao AN, Patil A, Brodnik ZD, Qiang L, España RA, Sullivan KA, Black MM, Baas PW. Pharmacologically increasing microtubule acetylation corrects stress-exacerbated effects of organophosphates on neurons. Traffic 2017; 18:433-441. [PMID: 28471062 DOI: 10.1111/tra.12489] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 04/30/2017] [Accepted: 05/01/2017] [Indexed: 12/18/2022]
Abstract
Many veterans of the 1990-1991 Gulf War contracted Gulf War Illness (GWI), a multisymptom disease that primarily affects the nervous system. Here, we treated cultures of human or rat neurons with diisopropyl fluorophosphate (DFP), an analog of sarin, one of the organophosphate (OP) toxicants to which the military veterans were exposed. All observed cellular defects produced by DFP were exacerbated by pretreatment with corticosterone or cortisol, which, in rat and human neurons, respectively, serves in our experiments to mimic the physical stress endured by soldiers during the war. To best mimic the disease, DFP was used below the level needed to inhibit acetylcholinesterase. We observed a diminution in the ratio of acetylated to total tubulin that was correctable by treatment with tubacin, a drug that inhibits HDAC6, the tubulin deacetylase. The reduction in microtubule acetylation was coupled with deficits in microtubule dynamics, which were correctable by HDAC6 inhibition. Deficits in mitochondrial transport and dopamine release were also improved by tubacin. Thus, various negative effects of the toxicant/stress exposures were at least partially correctable by restoring microtubule acetylation to a more normal status. Such an approach may have therapeutic benefit for individuals suffering from GWI or other neurological disorders linked to OP exposure.
Collapse
Affiliation(s)
- Anand N Rao
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Ankita Patil
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Zachary D Brodnik
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Liang Qiang
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Rodrigo A España
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | | | - Mark M Black
- Department of Anatomy and Cell Biology, Temple University, Philadelphia, Pennsylvania
| | - Peter W Baas
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania
| |
Collapse
|
48
|
Flannery BM, Bruun DA, Rowland DJ, Banks CN, Austin AT, Kukis DL, Li Y, Ford BD, Tancredi DJ, Silverman JL, Cherry SR, Lein PJ. Persistent neuroinflammation and cognitive impairment in a rat model of acute diisopropylfluorophosphate intoxication. J Neuroinflammation 2016; 13:267. [PMID: 27733171 PMCID: PMC5062885 DOI: 10.1186/s12974-016-0744-y] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 10/06/2016] [Indexed: 12/19/2022] Open
Abstract
Background Acute intoxication with organophosphorus (OP) cholinesterase inhibitors can trigger convulsions that progress to life-threatening status epilepticus. Survivors face long-term morbidity including mild-to-severe decline in memory. It is posited that neuroinflammation plays a key role in the pathogenesis of OP-induced neuropsychiatric deficits. Rigorous testing of this hypothesis requires preclinical models that recapitulate relevant phenotypic outcomes. Here, we describe a rat model of acute intoxication with the OP diisopropylfluorophosphate (DFP) that exhibits persistent neuroinflammation and cognitive impairment. Methods Neuroinflammation, neurodegeneration, and cognitive function were compared in adult male Sprague Dawley rats injected with an acutely toxic dose of DFP vs. vehicle controls at multiple time points up to 36 days post-exposure. Neuroinflammation was quantified using immunohistochemical biomarkers of microglia (ionized calcium-binding adapter molecule 1, IBA1) and activated astrocytes (glial fibrillary acidic protein, GFAP) and positron emission tomography (PET) imaging of [11C]-(R)-PK11195, a ligand for the 18-kDa mitochondrial membrane translocator protein (TSPO). FluoroJade-B staining was used to assess neurodegeneration; Pavlovian conditioning, to assess cognitive function. Results Animals exhibited moderate-to-severe seizures within minutes of DFP injection that continued for up to 6 h post-injection. As indicated by IBA1 and GFAP immunoreactivity and by PET imaging of TSPO, acute DFP intoxication triggered neuroinflammation in the hippocampus and cortex during the first 3 days that peaked at 7 days and persisted to 21 days post-exposure in most animals. Neurodegeneration was detected in multiple brain regions from 1 to 14 days post-exposure. All DFP-intoxicated animals exhibited significant deficits in contextual fear conditioning at 9 and 20 days post-exposure compared to vehicle controls. Whole-brain TSPO labeling positively correlated with seizure severity score, but did not correlate with performance in the contextual fear-conditioning task. Conclusions We describe a preclinical model in which acute DFP intoxication causes seizures, persistent neuroinflammation, neurodegeneration, and memory impairment. The extent of the neuroinflammatory response is influenced by seizure severity. However, the observation that a subset of animals with moderate seizures and minimal TSPO labeling exhibited cognitive deficits comparable to those of animals with severe seizures and significant TSPO labeling suggests that DFP may impair learning and memory circuitry via mechanisms independent of seizures or neuroinflammation.
Collapse
Affiliation(s)
- Brenna M Flannery
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, Davis, CA, 95616, USA
| | - Donald A Bruun
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, Davis, CA, 95616, USA
| | - Douglas J Rowland
- Center for Molecular and Genomic Imaging, University of California-Davis, Davis, CA, 95616, USA
| | - Christopher N Banks
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, Davis, CA, 95616, USA.,Current address: Office of Environmental Health Hazard Assessment, California Environmental Protection Agency, Sacramento, CA, 95812, USA
| | - Adam T Austin
- Department of Pediatrics, University of California-Davis Medical Center, Sacramento, CA, 95817, USA.,Current address: Navistar, Inc., 2701 Navistar Drive, Lisle, IL, 60532, USA
| | - David L Kukis
- Center for Molecular and Genomic Imaging, University of California-Davis, Davis, CA, 95616, USA
| | - Yonggang Li
- Division of Biomedical Sciences, University of California-Riverside School of Medicine, Riverside, CA, 92521, USA
| | - Byron D Ford
- Division of Biomedical Sciences, University of California-Riverside School of Medicine, Riverside, CA, 92521, USA
| | - Daniel J Tancredi
- Department of Pediatrics, University of California-Davis Medical Center, Sacramento, CA, 95817, USA
| | - Jill L Silverman
- Department of Psychiatry and Behavioral Sciences, University of California-Davis Medical Center, Sacramento, CA, 95817, USA
| | - Simon R Cherry
- Center for Molecular and Genomic Imaging, University of California-Davis, Davis, CA, 95616, USA
| | - Pamela J Lein
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California-Davis, Davis, CA, 95616, USA.
| |
Collapse
|
49
|
Pessah IN, Rogawski MA, Tancredi DJ, Wulff H, Zolkowska D, Bruun DA, Hammock BD, Lein PJ. Models to identify treatments for the acute and persistent effects of seizure-inducing chemical threat agents. Ann N Y Acad Sci 2016; 1378:124-136. [PMID: 27467073 DOI: 10.1111/nyas.13137] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 05/15/2016] [Accepted: 05/19/2016] [Indexed: 12/27/2022]
Abstract
Exposures to seizure-inducing chemical threat agents are a major public health concern. Of particular need is improved treatment to terminate convulsions and to prevent the long-term neurological sequelae in survivors. We are studying the organophosphorus cholinesterase inhibitor diisopropyl fluorophosphate (DFP) and the GABA receptor inhibitor tetramethylenedisulfotetramine (TETS), which arguably encompass the mechanistic spectrum of seizure-inducing chemical threats, with the goal of identifying therapeutic approaches with broad-spectrum efficacy. Research efforts have focused on developing translational models and translational diagnostic approaches, including (1) in vivo models of DFP- and TETS-induced seizures for studying neuropathological mechanisms and identifying treatment approaches; (2) in vivo imaging modalities for noninvasive longitudinal monitoring of neurological damage and response to therapeutic candidates; and (3) higher-throughput in vitro platforms for rapid screening of compounds to identify potential antiseizure and neuroprotective agents, as well as mechanistically relevant novel drug targets. This review summarizes our progress toward realizing these goals and discusses best practices and mechanistic insights derived from our modeling efforts.
Collapse
Affiliation(s)
- Isaac N Pessah
- Department of Molecular Biosciences, School of Veterinary Medicine
| | | | | | - Heike Wulff
- Department of Pharmacology, School of Medicine
| | | | - Donald A Bruun
- Department of Molecular Biosciences, School of Veterinary Medicine
| | - Bruce D Hammock
- Department of Entomology, College of Agricultural and Environmental Sciences, University of California, Davis, Davis, California
| | - Pamela J Lein
- Department of Molecular Biosciences, School of Veterinary Medicine.
| |
Collapse
|
50
|
Deshpande LS, Blair RE, Phillips KF, DeLorenzo RJ. Role of the calcium plateau in neuronal injury and behavioral morbidities following organophosphate intoxication. Ann N Y Acad Sci 2016; 1374:176-83. [PMID: 27327161 DOI: 10.1111/nyas.13122] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 05/04/2016] [Accepted: 05/10/2016] [Indexed: 12/28/2022]
Abstract
Organophosphate (OP) chemicals include nerve agents and pesticides, and there is a growing concern of OP-based chemical attacks against civilians. Current antidotes are essential in limiting immediate mortality associated with OP exposure. However, further research is needed to identify the molecular mechanisms underlying long-term neurological deficits following survival of OP toxicity in order to develop effective therapeutics. We have developed rat survival models of OP-induced status epilepticus (SE) that mimic chronic mortality and morbidity following OP intoxication. We have observed significant elevations in hippocampal calcium levels after OP SE that persisted for weeks following initial survival. Drugs inhibiting intracellular calcium-induced calcium release, such as dantrolene, levetiracetam, and carisbamate, lowered OP SE-mediated protracted calcium elevations. Given the critical role of calcium signaling in modulating behavior and cell death mechanisms, drugs targeted at preventing the development of the calcium plateau could enhance neuroprotection, help reduce morbidity, and improve outcomes following survival of OP SE.
Collapse
Affiliation(s)
- Laxmikant S Deshpande
- Departments of Neurology, Virginia Commonwealth University, Richmond, Virginia.,Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| | - Robert E Blair
- Departments of Neurology, Virginia Commonwealth University, Richmond, Virginia
| | - Kristin F Phillips
- Departments of Neurology, Virginia Commonwealth University, Richmond, Virginia
| | - Robert J DeLorenzo
- Departments of Neurology, Virginia Commonwealth University, Richmond, Virginia.,Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia
| |
Collapse
|