1
|
Dail ME, Brino MLM, Chambers JE. Effects of novel brain-penetrating oxime acetylcholinesterase reactivators on sarin surrogate-induced changes in rat brain gene expression. J Biochem Mol Toxicol 2021; 35:1-10. [PMID: 33682265 DOI: 10.1002/jbt.22755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 01/28/2021] [Accepted: 02/24/2021] [Indexed: 11/11/2022]
Abstract
Past assassinations and terrorist attacks demonstrate the need for a more effective antidote against nerve agents and other organophosphates (OP) that cause brain damage through inhibition of acetylcholinesterase (AChE). Our lab has invented a platform of phenoxyalkyl pyridinium oximes (US patent 9,277,937) that demonstrate the ability to cross the blood-brain barrier in in vivo rat tests with a sarin surrogate nitrophenyl isopropyl methylphosphonate (NIMP) and provide evidence of brain penetration by reducing cessation time of seizure-like behaviors, accumulation of glial fibrillary acidic protein (GFAP), and hippocampal neuropathology, as opposed to the currently approved oxime, 2-pyridine aldoxime methyl chloride (2-PAM). Using two of the novel oximes (Oximes 1 and 20), this project examined whether gene expression changes might help explain this protection. Expression changes in the piriform cortex were examined using polymerase chain reaction arrays for inflammatory cytokines and receptors. The hippocampus was examined via quantitative polymerase chain reaction for the expression of immediate-early genes involved in brain repair (Bdnf), increasing neurotoxicity (Fos), and apoptosis control (Jdp2, Bcl2l1, Bcl2l11). In the piriform cortex, NIMP significantly stimulated expression for the macrophage inflammatory proteins CCL4, IL-1A, and IL-1B. Oxime 20 by itself elicited the most changes. When it was given therapeutically post-NIMP, the largest change occurred: a 310-fold repression of the inflammatory cytokine, CCL12. In the hippocampus, NIMP increased the expression of the neurotoxicity marker Fos and decreased the expression of neuroprotective Bdnf and antiapoptotic Bcl2l1. Compared with 2-PAM, Oxime 20 stimulated Bcl2l1 expression more and returned expression closer to the vehicle control values.
Collapse
Affiliation(s)
- Mary E Dail
- Department of Comparative Biomedical Sciences, Center for Environmental Health Sciences, Mississippi State University, College of Veterinary Medicine, Mississippi State, United States, USA
| | - Meghan L M Brino
- Department of Comparative Biomedical Sciences, Center for Environmental Health Sciences, Mississippi State University, College of Veterinary Medicine, Mississippi State, United States, USA
| | - Janice E Chambers
- Department of Comparative Biomedical Sciences, Center for Environmental Health Sciences, Mississippi State University, College of Veterinary Medicine, Mississippi State, United States, USA
| |
Collapse
|
2
|
Garcia JM, Meek EC, Chambers JE. Novel pyridinium oximes enhance 24-h survivability against a lethal dose of nerve agent surrogate in adult female rats. Toxicology 2020; 446:152626. [PMID: 33159982 DOI: 10.1016/j.tox.2020.152626] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 10/08/2020] [Accepted: 11/01/2020] [Indexed: 02/06/2023]
Abstract
Our laboratory has developed novel substituted phenoxyalkyl pyridinium oximes (US Patent 9,227,937) designed to more efficiently penetrate the central nervous system to enhance survivability and attenuate seizure-like signs and neuropathology. Previous studies with male Sprague-Dawley rats indicated that survivability was enhanced against the nerve agent (sarin) surrogate, 4-nitrophenyl isopropyl methylphosphonate (NIMP). In this study, female adult Sprague-Dawley rats, tested specifically in diestrus, were challenged subcutaneously with lethal concentrations of NIMP (0.6 mg/kg). After development of seizure-like behavior and other signs of cholinergic toxicity, human equivalent dosages of atropine (0.65 mg/kg) and one of four oximes (2-PAM, or novel oxime 15, 20, or 55; 0.146 mmol/kg) or Multisol vehicle was administered alone or in binary oxime combinations intramuscularly. Animals were closely monitored for signs of cholinergic toxicity and 24 h survivability. Percentages of animals surviving the 24 h NIMP challenge dose were 35 % for 2-PAM and 55 %, 70 %, and 25 % for novel oximes 15, 20, and 55, respectively. Improvements in survival were also observed over 2-PAM alone with binary combinations of 2-PAM and either oxime 15 or oxime 20. Additionally, administration of novel oximes decreased the duration of seizure-like behavior as compared to 2-PAM suggesting that these oximes better penetrate the blood-brain barrier to mitigate central nervous system hypercholinergic activity. Efficacies were similar between females and previously reported males. These data indicate that the novel pyridinium oximes enhance survivability against lethal OP toxicity as compared to 2-PAM in adult female rats.
Collapse
Affiliation(s)
- Jason M Garcia
- Center for Environmental Health Sciences, Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, P.O. Box 6100, Mississippi State, MS, 39762, USA.
| | - Edward C Meek
- Center for Environmental Health Sciences, Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, P.O. Box 6100, Mississippi State, MS, 39762, USA.
| | - Janice E Chambers
- Center for Environmental Health Sciences, Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, P.O. Box 6100, Mississippi State, MS, 39762, USA.
| |
Collapse
|
3
|
Gore A, Neufeld-Cohen A, Egoz I, Baranes S, Gez R, Grauer E, Chapman S, Lazar S. Efficacy of retigabine in ameliorating the brain insult following sarin exposure in the rat. Toxicol Appl Pharmacol 2020; 395:114963. [PMID: 32209366 DOI: 10.1016/j.taap.2020.114963] [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: 01/05/2020] [Revised: 03/17/2020] [Accepted: 03/20/2020] [Indexed: 12/20/2022]
Abstract
BACKGROUND Sarin is an irreversible organophosphate cholinesterase inhibitor. Following toxic signs, an extensive long-term brain damage is often reported. Thus, we evaluated the efficacy of a novel anticonvulsant drug retigabine, a modulator of neuronal voltage gated K+ channels, as a neuroprotective agent following sarin exposure. METHODS Rats were exposed to 1 LD50 or 1.2 LD50 sarin and treated at onset of convulsions with retigabine (5 mg/kg, i.p.) alone or in combination with 5 mg/kg atropine and 7.5 mg/kg TMB-4 (TA) respectively. Brain biochemical and immunohistopathological analyses were processed 24 h and 1 week following 1 LD50 sarin exposure and at 4 weeks following exposure to 1.2 LD50 sarin. EEG activity in freely moving rats was also monitored by telemetry during the first week following exposure to 1.2 LD50 and behavior in the Open Field was evaluated 3 weeks post exposure. RESULTS Treatment with retigabine following 1 LD50 sarin exposure or in combination with TA following 1.2 LD50 exposure significantly reduced mortality rate compared to the non-treated groups. In both experiments, the retigabine treatment significantly reduced gliosis, astrocytosis and brain damage as measured by translocator protein (TSPO). Following sarin exposure the combined treatment (retigabine+ TA) significantly minimized epileptiform seizure activity. Finally, in the Open Field behavioral test the non-treated sarin group showed an increased mobility which was reversed by the combined treatment. CONCLUSIONS The M current modulator retigabine has been shown to be an effective adjunct therapy following OP induced convulsion, minimizing epileptiform seizure activity and attenuating the ensuing brain damage.
Collapse
Affiliation(s)
- Ariel Gore
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel.
| | - Adi Neufeld-Cohen
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Inbal Egoz
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Shlomi Baranes
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Rellie Gez
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Ettie Grauer
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Shira Chapman
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel
| | - Shlomi Lazar
- Department. of Pharmacology, Israel Institute for Biological Research, Ness Ziona 74100, Israel.
| |
Collapse
|
4
|
Kundrick E, Marrero-Rosado B, Stone M, Schultz C, Walker K, Lee-Stubbs RB, de Araujo Furtado M, Lumley LA. Delayed midazolam dose effects against soman in male and female plasma carboxylesterase knockout mice. Ann N Y Acad Sci 2020; 1479:94-107. [PMID: 32027397 DOI: 10.1111/nyas.14311] [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: 12/11/2019] [Revised: 01/13/2020] [Accepted: 01/19/2020] [Indexed: 01/30/2023]
Abstract
Chemical warfare nerve agent exposure leads to status epilepticus that may progress to epileptogenesis and severe brain pathology when benzodiazepine treatment is delayed. We evaluated the dose-response effects of delayed midazolam (MDZ) on toxicity induced by soman (GD) in the plasma carboxylesterase knockout (Es1-/- ) mouse, which, similar to humans, lacks plasma carboxylesterase. Initially, we compared the median lethal dose (LD50 ) of GD exposure in female Es1-/- mice across estrous with male mice and observed a greater LD50 during estrus compared with proestrus or with males. Subsequently, male and female GD-exposed Es1-/- mice treated with a dose range of MDZ 40 min after seizure onset were evaluated for survivability, seizure activity, and epileptogenesis. GD-induced neuronal loss and microglial activation were evaluated 2 weeks after exposure. Similar to our previous observations in rats, delayed treatment with MDZ dose-dependently increased survival and reduced seizure severity in GD-exposed mice, but was unable to prevent epileptogenesis, neuronal loss, or gliosis. These results suggest that MDZ is beneficial against GD exposure, even when treatment is delayed, but that adjunct therapies to enhance protection need to be identified. The Es1-/- mouse GD exposure model may be useful to screen for improved medical countermeasures against nerve agent exposure.
Collapse
Affiliation(s)
- Erica Kundrick
- US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Brenda Marrero-Rosado
- US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Michael Stone
- US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Caroline Schultz
- US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Katie Walker
- US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | - Robyn B Lee-Stubbs
- US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| | | | - Lucille A Lumley
- US Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland
| |
Collapse
|
5
|
Chapman S, Lazar S, Gez R, Rabinovitz I, Yaakov G, Grauer E. Lung damage following whole body, but not intramuscular, exposure to median lethality dose of sarin: findings in rats and guinea pigs. Inhal Toxicol 2019; 31:203-211. [PMID: 31359796 DOI: 10.1080/08958378.2019.1644402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Objective: Sarin is an irreversible organophosphate cholinesterase inhibitor and a highly toxic, volatile warfare agent. Rats and guinea pigs exposed to sarin display cholinergic excitotoxicity which includes hyper-salivation, respiratory distress, tremors, seizures, and death. Here we focused on the characterization of the airways injury induced by direct exposure of the lungs to sarin vapor and compared it to that induced by the intramuscularly route. Materials and methods: Rats were exposed to sarin either in vapor (∼1LCT50, 34.2 ± 0.8 µg/l/min, 10 min) or by i.m. (∼1LD50, 80 µg/kg), and lung injury was evaluated by broncho-alveolar lavage (BAL). Results and discussion: BAL analysis revealed route-dependent effects in rats: vapor exposed animals showed elevation of inflammatory cytokines, protein, and neutrophil cells. These elevations were seen at 24 h and were still significantly higher compared to control values at 1 week following vapor exposure. These elevations were not detected in rats exposed to sarin i.m. Histological evaluation of the brains revealed typical changes following sarin poisoning independent of the route of administration. The airways damage following vapor exposure in rats was also compared to that induced in guinea pigs. The latter showed increased eosinophilia and histamine levels that constitutes an anaphylactic response not seen in rats. Conclusions: These data clearly point out the importance of using the appropriate route of administration in studying the deleterious effects of volatile nerve agents, as well as the selection of the appropriate animal species. Since airways form major target organs for the development of injury following inhalation toxicity, they should be included in any comprehensive evaluation of countermeasures efficacy.
Collapse
Affiliation(s)
- Shira Chapman
- a Department of Pharmacology, Israel Institute for Biological Research (IIBR) , Ness-Ziona , Israel
| | - Shlomi Lazar
- a Department of Pharmacology, Israel Institute for Biological Research (IIBR) , Ness-Ziona , Israel
| | - Rellie Gez
- a Department of Pharmacology, Israel Institute for Biological Research (IIBR) , Ness-Ziona , Israel
| | - Ishai Rabinovitz
- a Department of Pharmacology, Israel Institute for Biological Research (IIBR) , Ness-Ziona , Israel
| | - Guy Yaakov
- a Department of Pharmacology, Israel Institute for Biological Research (IIBR) , Ness-Ziona , Israel
| | - Ettie Grauer
- a Department of Pharmacology, Israel Institute for Biological Research (IIBR) , Ness-Ziona , Israel
| |
Collapse
|