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Rezk S, Althani A, Abd-elmaksoud A, Kassab M, Farag A, Lashen S, Cenciarelli C, Caceci T, Marei H. Effects of estrogen on Survival and Neuronal Differentiation of adult human olfactory bulb neural stem Cells Transplanted into Spinal Cord Injured Rats.. [DOI: 10.1101/571950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
AbstractIn the present study we developed an excitotoxic spinal cord injury (SCI) model using kainic acid (KA) to evaluate of the therapeutic potential of human olfactory bulb neural stem cells (h-OBNSCs) for spinal cord injury (SCI). In a previous study, we assessed the therapeutic potential of these cells for SCI; all transplanted animals showed successful engraftment. These cells differentiated predominantly as astrocytes, not motor neurons, so no improvement in motor functions was detected. In the current study we used estrogen as neuroprotective therapy before transplantation of OBNSCs to preserve some of endogenous neurons and enhance the differentiation of these cells towards neurons. The present work demonstrated that the h-GFP-OBNSCs were able to survive for more than eight weeks after sub-acute transplantation into injured spinal cord. Stereological quantification of OBNSCs showed approximately a 2.38-fold increase in the initial cell population transplanted. 40.91% of OBNSCs showed differentiation along the neuronal lineages, which was the predominant fate of these cells. 36.36% of the cells differentiated into mature astrocytes; meanwhile 22.73% of the cells differentiated into oligodendrocytes. Improvement in motor functions was also detected after cell transplantation.
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Yao X, Zhang Y, Hao J, Duan HQ, Zhao CX, Sun C, Li B, Fan BY, Wang X, Li WX, Fu XH, Hu Y, Liu C, Kong XH, Feng SQ. Deferoxamine promotes recovery of traumatic spinal cord injury by inhibiting ferroptosis. Neural Regen Res 2019; 14:532-541. [PMID: 30539824 PMCID: PMC6334606 DOI: 10.4103/1673-5374.245480] [Citation(s) in RCA: 157] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Ferroptosis is an iron-dependent novel cell death pathway. Deferoxamine, a ferroptosis inhibitor, has been reported to promote spinal cord injury repair. It has yet to be clarified whether ferroptosis inhibition represents the mechanism of action of Deferoxamine on spinal cord injury recovery. A rat model of Deferoxamine at thoracic 10 segment was established using a modified Allen's method. Ninety 8-week-old female Wistar rats were used. Rats in the Deferoxamine group were intraperitoneally injected with 100 mg/kg Deferoxamine 30 minutes before injury. Simultaneously, the Sham and Deferoxamine groups served as controls. Drug administration was conducted for 7 consecutive days. The results were as follows: (1) Electron microscopy revealed shrunken mitochondria in the spinal cord injury group. (2) The Basso, Beattie and Bresnahan locomotor rating score showed that recovery of the hindlimb was remarkably better in the Deferoxamine group than in the spinal cord injury group. (3) The iron concentration was lower in the Deferoxamine group than in the spinal cord injury group after injury. (4) Western blot assay revealed that, compared with the spinal cord injury group, GPX4, xCT, and glutathione expression was markedly increased in the Deferoxamine group. (5) Real-time polymerase chain reaction revealed that, compared with the Deferoxamine group, mRNA levels of ferroptosis-related genes Acyl-CoA synthetase family member 2 (ACSF2) and iron-responsive element-binding protein 2 (IREB2) were up-regulated in the Deferoxamine group. (6) Deferoxamine increased survival of neurons and inhibited gliosis. These findings confirm that Deferoxamine can repair spinal cord injury by inhibiting ferroptosis. Targeting ferroptosis is therefore a promising therapeutic approach for spinal cord injury.
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Affiliation(s)
- Xue Yao
- Department of Orthopedics, Tianjin Medical University General Hospital; State Key Laboratory of Medicinal Chemical Biology, Nankai University; International Science and Technology Cooperation Base of Spinal Cord Injury, Tianjin, China
| | - Yan Zhang
- Department of Orthopedics, Tianjin Medical University General Hospital; International Science and Technology Cooperation Base of Spinal Cord Injury, Tianjin, China
| | - Jian Hao
- Department of Orthopedics, Tianjin Medical University General Hospital; Department of Orthopedics, Nankai Hospital, Tianjin, China
| | - Hui-Quan Duan
- Department of Orthopedics, Tianjin Medical University General Hospital; International Science and Technology Cooperation Base of Spinal Cord Injury, Tianjin, China
| | - Chen-Xi Zhao
- Department of Orthopedics, Tianjin Medical University General Hospital; International Science and Technology Cooperation Base of Spinal Cord Injury, Tianjin, China
| | - Chao Sun
- Department of Orthopedics, Tianjin Medical University General Hospital; International Science and Technology Cooperation Base of Spinal Cord Injury, Tianjin, China
| | - Bo Li
- Department of Orthopedics, Tianjin Medical University General Hospital; International Science and Technology Cooperation Base of Spinal Cord Injury, Tianjin, China
| | - Bao-You Fan
- Department of Orthopedics, Tianjin Medical University General Hospital; International Science and Technology Cooperation Base of Spinal Cord Injury, Tianjin, China
| | - Xu Wang
- Department of Orthopedics, Tianjin Medical University General Hospital; International Science and Technology Cooperation Base of Spinal Cord Injury, Tianjin, China
| | - Wen-Xiang Li
- Department of Orthopedics, Tianjin Medical University General Hospital; International Science and Technology Cooperation Base of Spinal Cord Injury, Tianjin, China
| | - Xuan-Hao Fu
- Department of Orthopedics, Tianjin Medical University General Hospital; International Science and Technology Cooperation Base of Spinal Cord Injury, Tianjin, China
| | - Yong Hu
- Department of Orthopedic and Traumatology, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China
| | - Chang Liu
- School of Medicine, Nankai University, Tianjin, China
| | | | - Shi-Qing Feng
- Department of Orthopedics, Tianjin Medical University General Hospital; International Science and Technology Cooperation Base of Spinal Cord Injury; Tianjin Neurological Institute, Key Laboratory of Post-Neuroinjury Neuro-repair and Regeneration in Central Nervous System, Ministry of Education and Tianjin City, Tianjin, China
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Nardone R, Florea C, Höller Y, Brigo F, Versace V, Lochner P, Golaszewski S, Trinka E. Rodent, large animal and non-human primate models of spinal cord injury. ZOOLOGY 2017; 123:101-114. [PMID: 28720322 DOI: 10.1016/j.zool.2017.06.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 06/02/2017] [Accepted: 06/02/2017] [Indexed: 01/05/2023]
Abstract
In this narrative review we aimed to assess the usefulness of the different animal models in identifying injury mechanisms and developing therapies for humans suffering from spinal cord injury (SCI). Results obtained from rodent studies are useful but, due to the anatomical, molecular and functional differences, confirmation of these findings in large animals or non-human primates may lead to basic discoveries that cannot be made in rodent models and that are more useful for developing treatment strategies in humans. SCI in dogs can be considered as intermediate between rodent models and human clinical trials, but the primate models could help to develop appropriate methods that might be more relevant to humans. Ideally, an animal model should meet the requirements of availability and repeatability as well as reproduce the anatomical features and the clinical pathological changing process of SCI. An animal model that completely simulates SCI in humans does not exist. The different experimental models of SCI have advantages and disadvantages for investigating the different aspects of lesion development, recovery mechanisms and potential therapeutic interventions. The potential advantages of non-human primate models include genetic similarities, similar caliber/length of the spinal cord as well as biological and physiological responses to injury which are more similar to humans. Among the potential disadvantages, high operating costs, infrastructural requirements and ethical concerns should be considered. The translation from experimental repair strategies to clinical applications needs to be investigated in future carefully designed studies.
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Affiliation(s)
- Raffaele Nardone
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Ignaz-Harrer-Str. 79, A-5020, Salzburg, Austria; Department of Neurology, Franz Tappeiner Hospital, Via Rossini 5, I-39012, Merano, Italy; Spinal Cord Injury and Tissue Regeneration Center, Paracelsus Medical University, Ignaz-Harrer-Str. 79, A-5020, Salzburg, Austria.
| | - Cristina Florea
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Ignaz-Harrer-Str. 79, A-5020, Salzburg, Austria
| | - Yvonne Höller
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Ignaz-Harrer-Str. 79, A-5020, Salzburg, Austria
| | - Francesco Brigo
- Department of Neurology, Franz Tappeiner Hospital, Via Rossini 5, I-39012, Merano, Italy; Department of Neurosciences, Biomedicine and Movement Sciences, Section of Clinical Neurology, University of Verona, Piazzale L.A. Scuro, I-37134 Verona, Italy
| | - Viviana Versace
- Department of Neurorehabilitation, Hospital of Vipiteno, Via Santa Margherita 24, I-39049, Italy
| | - Piergiorgio Lochner
- Department of Neurology, Saarland University Medical Center, Kirrberger-Str. 100, D-66421 Homburg, Germany
| | - Stefan Golaszewski
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Ignaz-Harrer-Str. 79, A-5020, Salzburg, Austria
| | - Eugen Trinka
- Department of Neurology, Christian Doppler Klinik, Paracelsus Medical University, Ignaz-Harrer-Str. 79, A-5020, Salzburg, Austria; Spinal Cord Injury and Tissue Regeneration Center, Paracelsus Medical University, Ignaz-Harrer-Str. 79, A-5020, Salzburg, Austria
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Altered Cerebellar Circuitry following Thoracic Spinal Cord Injury in Adult Rats. Neural Plast 2016; 2016:8181393. [PMID: 27504204 PMCID: PMC4967704 DOI: 10.1155/2016/8181393] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2016] [Accepted: 06/20/2016] [Indexed: 01/10/2023] Open
Abstract
Cerebellar function is critical for coordinating movement and motor learning. However, events occurring in the cerebellum following spinal cord injury (SCI) have not been investigated in detail. We provide evidence of SCI-induced cerebellar synaptic changes involving a loss of granule cell parallel fiber input to distal regions of the Purkinje cell dendritic tree. This is accompanied by an apparent increase in synaptic contacts to Purkinje cell proximal dendrites, presumably from climbing fibers originating in the inferior olive. We also observed an early stage injury-induced decrease in the levels of cerebellin-1, a synaptic organizing molecule that is critical for establishing and maintaining parallel fiber-Purkinje cell synaptic integrity. Interestingly, this transsynaptic reorganizational pattern is consistent with that reported during development and in certain transgenic mouse models. To our knowledge, such a reorganizational event has not been described in response to SCI in adult rats. Regardless, the novel results of this study are important for understanding SCI-induced synaptic changes in the cerebellum, which may prove critical for strategies focusing on promoting functional recovery.
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Blizzard CA, Lee KM, Dickson TC. Inducing Chronic Excitotoxicity in the Mouse Spinal Cord to Investigate Lower Motor Neuron Degeneration. Front Neurosci 2016; 10:76. [PMID: 26973454 PMCID: PMC4773442 DOI: 10.3389/fnins.2016.00076] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 02/17/2016] [Indexed: 12/13/2022] Open
Abstract
We report the methodology for the chronic delivery of an excitotoxin to the mouse spinal cord via surgically implanted osmotic mini-pumps. Previous studies have investigated the effect of chronic application of excitotoxins in the rat, however there has been little translation of this model to the mouse. Using mice that express yellow fluorescent protein (YFP), motor neuron and neuromuscular junction alterations can be investigate following targeted, long-term (28 days) exposure to the α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor excitotoxin, kainic acid. By targeting the L3-4 region of the lumbar spinal cord, with insertion of an intrathecal catheter into the subarachnoid space at L5, chronic application of the kainic acid results in slow excitotoxic death in the anterior ventral horn, with a significant (P < 0.05) reduction in the number of SMI-32 immunopositive neurons present after 28 days infusion. Use of the Thy1-YFP mice provides unrivaled visualization of the neuromuscular junction and enables the resultant distal degeneration in skeletal muscle to be observed. Both neuromuscular junction retraction at the gastrocnemius muscle and axonal fragmentation in the sciatic nerve were observed after chronic infusion of kainic acid for 28 days. Lower motor neuron, and distal neuromuscular junction, degeneration are pathological hallmarks of the devastating neurodegenerative disease Amyotrophic Lateral Sclerosis (ALS). This mouse model will be advantageous for increasing our understanding of how the pathophysiological phenomena associated with this disease can lead to lower motor neuron loss and distal pathology, as well as providing a robust in vivo platform to test therapeutic interventions directed at excitotoxic mechanisms.
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Affiliation(s)
- Catherine A. Blizzard
- Menzies Institute for Medical Research, University of TasmaniaHobart, TAS, Australia
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The Cotransplantation of Olfactory Ensheathing Cells with Bone Marrow Mesenchymal Stem Cells Exerts Antiapoptotic Effects in Adult Rats after Spinal Cord Injury. Stem Cells Int 2015; 2015:516215. [PMID: 26294918 PMCID: PMC4532957 DOI: 10.1155/2015/516215] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Revised: 06/24/2015] [Accepted: 06/29/2015] [Indexed: 01/09/2023] Open
Abstract
The mechanisms behind the repairing effects of the cotransplantation of olfactory ensheathing cells (OECs) with bone marrow mesenchymal stromal cells (BMSCs) have not been fully understood. Therefore, we investigated the effects of the cotransplantation of OECs with BMSCs on antiapoptotic effects in adult rats for which the models of SCI are induced. We examined the changes in body weight, histopathological changes, apoptosis, and the expressions of apoptosis-related proteins after 14 days and 28 days after transplantation. We also assessed animal locomotion using BBB test. We found that treatment with OECs and BMSCs had a remissive effect on behavioral outcome and histopathological changes induced SCI. Furthermore, we observed the significant antiapoptotic effect on cotransplant treated group. In addition, cotransplantation of OECs with BMSCs was found to have more significant repairing effect than that of OECs or BMSCs alone. Furthermore, the recovery of hind limb could be related to antiapoptotic effect of OECs and BMSCs through downregulating the apoptotic pathways. Finally, our data suggested the cotransplantation of OECs with BMSCs holds promise for a potential cure after SCI through the ability to incorporate into the spinal cord.
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Blizzard CA, Southam KA, Dawkins E, Lewis KE, King AE, Clark JA, Dickson TC. Identifying the primary site of pathogenesis in amyotrophic lateral sclerosis - vulnerability of lower motor neurons to proximal excitotoxicity. Dis Model Mech 2015; 8:215-24. [PMID: 25740331 PMCID: PMC4348560 DOI: 10.1242/dmm.018606] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 01/20/2015] [Indexed: 12/13/2022] Open
Abstract
There is a desperate need for targeted therapeutic interventions that slow the progression of amyotrophic lateral sclerosis (ALS). ALS is a disorder with heterogeneous onset, which then leads to common final pathways involving multiple neuronal compartments that span both the central and peripheral nervous system. It is believed that excitotoxic mechanisms might play an important role in motor neuron death in ALS. However, little is known about the mechanisms by which excitotoxicity might lead to the neuromuscular junction degeneration that characterizes ALS, or about the site at which this excitotoxic cascade is initiated. Using a novel compartmentalised model of site-specific excitotoxin exposure in lower motor neurons in vitro, we found that spinal motor neurons are vulnerable to somatodendritic, but not axonal, excitotoxin exposure. Thus, we developed a model of somatodendritic excitotoxicity in vivo using osmotic mini pumps in Thy-1-YFP mice. We demonstrated that in vivo cell body excitotoxin exposure leads to significant motor neuron death and neuromuscular junction (NMJ) retraction. Using confocal real-time live imaging of the gastrocnemius muscle, we found that NMJ remodelling preceded excitotoxin-induced NMJ degeneration. These findings suggest that excitotoxicity in the spinal cord of individuals with ALS might result in a die-forward mechanism of motor neuron death from the cell body outward, leading to initial distal plasticity, followed by subsequent pathology and degeneration.
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Affiliation(s)
- Catherine A Blizzard
- Menzies Research Institute Tasmania, University of Tasmania, Hobart, TAS 7000, Australia
| | - Katherine A Southam
- Menzies Research Institute Tasmania, University of Tasmania, Hobart, TAS 7000, Australia
| | - Edgar Dawkins
- Menzies Research Institute Tasmania, University of Tasmania, Hobart, TAS 7000, Australia
| | - Katherine E Lewis
- Menzies Research Institute Tasmania, University of Tasmania, Hobart, TAS 7000, Australia
| | - Anna E King
- Wicking Dementia Research and Education Centre, University of Tasmania, Hobart, TAS 7000, Australia
| | - Jayden A Clark
- Menzies Research Institute Tasmania, University of Tasmania, Hobart, TAS 7000, Australia
| | - Tracey C Dickson
- Menzies Research Institute Tasmania, University of Tasmania, Hobart, TAS 7000, Australia
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8
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Woller SA, Hook MA. Opioid administration following spinal cord injury: implications for pain and locomotor recovery. Exp Neurol 2013; 247:328-41. [PMID: 23501709 PMCID: PMC3742731 DOI: 10.1016/j.expneurol.2013.03.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2012] [Revised: 03/04/2013] [Accepted: 03/06/2013] [Indexed: 12/18/2022]
Abstract
Approximately one-third of people with a spinal cord injury (SCI) will experience persistent neuropathic pain following injury. This pain negatively affects quality of life and is difficult to treat. Opioids are among the most effective drug treatments, and are commonly prescribed, but experimental evidence suggests that opioid treatment in the acute phase of injury can attenuate recovery of locomotor function. In fact, spinal cord injury and opioid administration share several common features (e.g. central sensitization, excitotoxicity, aberrant glial activation) that have been linked to impaired recovery of function, as well as the development of pain. Despite these effects, the interactions between opioid use and spinal cord injury have not been fully explored. A review of the literature, described here, suggests that caution is warranted when administering opioids after SCI. Opioid administration may synergistically contribute to the pathology of SCI to increase the development of pain, decrease locomotor recovery, and leave individuals at risk for infection. Considering these negative implications, it is important that guidelines are established for the use of opioids following spinal cord and other central nervous system injuries.
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Affiliation(s)
- Sarah A Woller
- Texas A&M Institute for Neuroscience, Department of Psychology, Texas A&M University, College Station, TX 77843-4235, USA.
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Kuzhandaivel A, Nistri A, Mazzone GL, Mladinic M. Molecular Mechanisms Underlying Cell Death in Spinal Networks in Relation to Locomotor Activity After Acute Injury in vitro. Front Cell Neurosci 2011; 5:9. [PMID: 21734866 PMCID: PMC3119860 DOI: 10.3389/fncel.2011.00009] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Accepted: 06/08/2011] [Indexed: 12/12/2022] Open
Abstract
Understanding the pathophysiological changes triggered by an acute spinal cord injury is a primary goal to prevent and treat chronic disability with a mechanism-based approach. After the primary phase of rapid cell death at the injury site, secondary damage occurs via autodestruction of unscathed tissue through complex cell-death mechanisms that comprise caspase-dependent and caspase-independent pathways. To devise novel neuroprotective strategies to restore locomotion, it is, therefore, necessary to focus on the death mechanisms of neurons and glia within spinal locomotor networks. To this end, the availability of in vitro preparations of the rodent spinal cord capable of expressing locomotor-like oscillatory patterns recorded electrophysiologically from motoneuron pools offers the novel opportunity to correlate locomotor network function with molecular and histological changes long after an acute experimental lesion. Distinct forms of damage to the in vitro spinal cord, namely excitotoxic stimulation or severe metabolic perturbation (with oxidative stress, hypoxia/aglycemia), can be applied with differential outcome in terms of cell types and functional loss. In either case, cell death is a delayed phenomenon developing over several hours. Neurons are more vulnerable to excitotoxicity and more resistant to metabolic perturbation, while the opposite holds true for glia. Neurons mainly die because of hyperactivation of poly(ADP-ribose) polymerase-1 (PARP-1) with subsequent DNA damage and mitochondrial energy collapse. Conversely, glial cells die predominantly by apoptosis. It is likely that early neuroprotection against acute spinal injury may require tailor-made drugs targeted to specific cell-death processes of certain cell types within the locomotor circuitry. Furthermore, comparison of network size and function before and after graded injury provides an estimate of the minimal network membership to express the locomotor program.
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Yin Z, Lee E, Ni M, Jiang H, Milatovic D, Rongzhu L, Farina M, Rocha JBT, Aschner M. Methylmercury-induced alterations in astrocyte functions are attenuated by ebselen. Neurotoxicology 2011; 32:291-9. [PMID: 21300091 PMCID: PMC3079013 DOI: 10.1016/j.neuro.2011.01.004] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 12/21/2010] [Accepted: 01/08/2011] [Indexed: 12/26/2022]
Abstract
Methylmercury (MeHg) preferentially accumulates in glia of the central nervous system (CNS), but its toxic mechanisms have yet to be fully recognized. In the present study, we tested the hypothesis that MeHg induces neurotoxicity via oxidative stress mechanisms, and that these effects are attenuated by the antioxidant, ebselen. Rat neonatal primary cortical astrocytes were pretreated with or without 10 μM ebselen for 2h followed by MeHg (0, 1, 5, and 10 μM) treatments. MeHg-induced changes in astrocytic [(3)H]-glutamine uptake were assessed along with changes in mitochondrial membrane potential (ΔΨ(m)), using the potentiometric dye tetramethylrhodamine ethyl ester (TMRE). Western blot analysis was used to detect MeHg-induced ERK (extracellular-signal related kinase) phosphorylation and caspase-3 activation. MeHg treatment significantly decreased (p<0.05) astrocytic [(3)H]-glutamine uptake at all time points and concentrations. Ebselen fully reversed MeHg's (1 μM) effect on [(3)H]-glutamine uptake at 1 min. At higher MeHg concentrations, ebselen partially reversed the MeHg-induced astrocytic inhibition of [(3)H]-glutamine uptake [at 1 min (5 and 10 μM) (p<0.05); 5 min (1, 5 and 10 μM) (p<0.05)]. MeHg treatment (1h) significantly (p<0.05) dissipated the ΔΨ(m) in astrocytes as evidenced by a decrease in mitochondrial TMRE fluorescence. Ebselen fully reversed the effect of 1 μM MeHg treatment for 1h on astrocytic ΔΨ(m) and partially reversed the effect of 5 and 10 μM MeHg treatments for 1h on ΔΨ(m). In addition, ebselen inhibited MeHg-induced phosphorylation of ERK (p<0.05) and blocked MeHg-induced activation of caspase-3 (p<0.05-0.01). These results are consistent with the hypothesis that MeHg exerts its toxic effects via oxidative stress and that the phosphorylation of ERK and the dissipation of the astrocytic mitochondrial membrane potential are involved in MeHg toxicity. In addition, the protective effects elicited by ebselen reinforce the idea that organic selenocompounds represent promising strategies to counteract MeHg-induced neurotoxicity.
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MESH Headings
- Analysis of Variance
- Animals
- Animals, Newborn
- Antioxidants/pharmacology
- Astrocytes/drug effects
- Astrocytes/metabolism
- Astrocytes/pathology
- Azoles/pharmacology
- Blotting, Western
- Caspase 3/metabolism
- Cells, Cultured
- Cytoprotection
- Dose-Response Relationship, Drug
- Environmental Pollutants/toxicity
- Extracellular Signal-Regulated MAP Kinases/metabolism
- Glutamine/metabolism
- Isoindoles
- Membrane Potential, Mitochondrial/drug effects
- Mercury Poisoning, Nervous System/etiology
- Mercury Poisoning, Nervous System/metabolism
- Mercury Poisoning, Nervous System/pathology
- Methylmercury Compounds/toxicity
- Microscopy, Fluorescence
- Mitochondria/drug effects
- Mitochondria/metabolism
- Neuroprotective Agents/pharmacology
- Organoselenium Compounds/pharmacology
- Oxidative Stress/drug effects
- Phosphorylation
- Rats
- Rats, Sprague-Dawley
- Time Factors
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Affiliation(s)
- Zhaobao Yin
- Departments of Pediatrics and Pharmacology, the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Eunsook Lee
- Department of Physiology, Meharry Medical College, Nashville, Tennessee
| | - Mingwei Ni
- Departments of Pediatrics and Pharmacology, the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Haiyan Jiang
- Departments of Pediatrics and Pharmacology, the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Dejan Milatovic
- Departments of Pediatrics and Pharmacology, the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Lu Rongzhu
- Departments of Pediatrics and Pharmacology, the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Marcelo Farina
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | - Joao B. T. Rocha
- Departamento de Bioquímica, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Michael Aschner
- Departments of Pediatrics and Pharmacology, the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, Tennessee
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11
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Huh JW, Widing AG, Raghupathi R. Differential effects of injury severity on cognition and cellular pathology after contusive brain trauma in the immature rat. J Neurotrauma 2011; 28:245-57. [PMID: 21091272 DOI: 10.1089/neu.2010.1639] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Although diffuse brain damage has been suggested to be the predominant predictor of neurological morbidity following closed head injury in infants and children, the presence of contusions also predicts long-term neurobehavioral dysfunction. Contusive brain trauma in the 17-day-old rat resulted in neurodegeneration and caspase activation in the cortex at 1 day, and in the thalamus at 3 days post-injury, and to a greater extent following a deeper impact. Cortical tissue loss in the 4-mm impact group was significantly greater than that in the 3-mm impact group (p < 0.05), and exhibited a time-dependent increase over the first 3 weeks post-injury. Traumatic axonal injury was observed in the white matter tracts below the site of impact at 1 day, and in the corpus callosum at 3 days, to a greater extent following 4-mm impact. In contrast, cellular caspase-3 activation in these white matter tracts was only observed at 24 h post-injury and was not affected by impact depth. Similarly, neurodegeneration and caspase activation in the hippocampus was restricted to the dentate gyrus and occurred to a similar extent in both injured groups. Only the 4-mm impact group exhibited learning deficits in the first week (p < 0.0001) that was sustained until the third week post-injury (p < 0.0001), while deficits in the 3-mm impact group were seen only at 3 weeks post-injury (p < 0.02). These observations demonstrate that increasing severity of injury in immature animals does not uniformly increase the extent of cellular damage, and that the progression of tissue damage and behavioral deficits varies as a function of injury severity.
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Affiliation(s)
- Jimmy W Huh
- Department of Anesthesiology and Critical Care, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
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12
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Xu GY, Liu S, Hughes MG, McAdoo DJ. Glutamate-induced losses of oligodendrocytes and neurons and activation of caspase-3 in the rat spinal cord. Neuroscience 2008; 153:1034-47. [PMID: 18423997 DOI: 10.1016/j.neuroscience.2008.02.065] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2007] [Revised: 02/05/2008] [Accepted: 02/15/2008] [Indexed: 11/20/2022]
Abstract
The toxicity of released glutamate contributes substantially to secondary cell death following spinal cord injury (SCI). In this work, the extent and time courses of glutamate-induced losses of neurons and oligodendrocytes are established. Glutamate was administered into the spinal cords of anesthetized rats at approximately the concentration and duration of its release following SCI. Cells in normal tissue, in tissue exposed to artificial cerebrospinal fluid and in tissue exposed to glutamate were counted on a confocal system in control animals and from 6 h to 28 days after treatment to assess cell losses. Oligodendrocytes were identified by staining with antibody CC-1 and neurons by immunostaining for Neuronal Nuclei (NeuN) or Neurofilament H. The density of oligodendrocytes declined precipitously in the first 6 h after exposure to glutamate, and then relatively little from 24 h to 28 days post-exposure. Similarly, neuron densities first declined rapidly, but at a decreasing rate, from 0 h to 72 h post-glutamate exposure and did not change significantly from 72 h to 28 days thereafter. The nuclei of many cells strongly and specifically stained for activated caspase-3, an indicator of apoptosis, in response to exposure to glutamate. Caspase-3 was localized to the nucleus and may participate in apoptotic cell death. However, persistence of caspase-3 staining for at least a week after exposure to glutamate during little to no loss of oligodendrocytes and neurons demonstrates that elevation of caspase-3 does not necessarily lead to rapid cell death. Beyond about 48 h after exposure to glutamate, locomotor function began to recover while cell numbers stabilized or declined slowly, demonstrating that functional recovery in the experiments presented involves processes other than replacement of oligodendrocytes and/or neurons.
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Affiliation(s)
- G-Y Xu
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-1043, USA
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Yin Z, Aschner JL, dos Santos AP, Aschner M. Mitochondrial-dependent manganese neurotoxicity in rat primary astrocyte cultures. Brain Res 2008; 1203:1-11. [PMID: 18313649 DOI: 10.1016/j.brainres.2008.01.079] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Revised: 12/13/2007] [Accepted: 01/22/2008] [Indexed: 12/15/2022]
Abstract
Chronic exposure to excessive levels of Mn results in a movement disorder termed manganism, which resembles Parkinson's disease (PD). The pathogenic mechanisms underlying this disorder are not fully understood. Several lines of evidence implicate astrocytes as an early target of Mn neurotoxicity. In the present study, we investigated the effects of Mn on mitochondrial function. Primary astrocyte cultures were prepared from cerebral cortices of one-day-old Sprague-Dawley rats. We have examined the cellular toxicity of Mn and its effects on the phosphorylation of extracellular signal-regulated kinase (ERK) and activation of the precursor protein of caspase-3. The potentiometric dye, tetramethyl rhodamine ethyl ester (TMRE), was used to assess the effect of Mn on astrocytic mitochondrial inner membrane potential (DeltaPsi(m)). Our studies show that, in a concentration-dependent manner, Mn induces significant (p<0.05) activation of astrocyte caspase-3 and phosphorylated extracellular signal-regulated kinase (p-ERK). Mn treatment (1 and 6 h) also significantly (p<0.01) dissipates the DeltaPsi(m) in astrocytes as evidenced by a decrease in mitochondrial TMRE fluorescence. These results suggest that activations of astrocytic caspase-3 and ERK are involved in Mn-induced neurotoxicity via mitochondrial-dependent pathways.
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Affiliation(s)
- Zhaoobao Yin
- Department of Pediatrics, Vanderbilt University Medical Center, TN, USA
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Adjan VV, Hauser KF, Bakalkin G, Yakovleva T, Gharibyan A, Scheff SW, Knapp PE. Caspase-3 activity is reduced after spinal cord injury in mice lacking dynorphin: differential effects on glia and neurons. Neuroscience 2007; 148:724-36. [PMID: 17698296 DOI: 10.1016/j.neuroscience.2007.05.053] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Revised: 05/16/2007] [Accepted: 05/24/2007] [Indexed: 12/12/2022]
Abstract
Dynorphins are endogenous opioid peptide products of the prodynorphin gene. An extensive literature suggests that dynorphins have deleterious effects on CNS injury outcome. We thus examined whether a deficiency of dynorphin would protect against tissue damage after spinal cord injury (SCI), and if individual cell types would be specifically affected. Wild-type and prodynorphin(-/-) mice received a moderate contusion injury at 10th thoracic vertebrae (T10). Caspase-3 activity at the injury site was significantly decreased in tissue homogenates from prodynorphin(-/-) mice after 4 h. We examined frozen sections at 4 h post-injury by immunostaining for active caspase-3. At 3-4 mm rostral or caudal to the injury, >90% of all neurons, astrocytes and oligodendrocytes expressed active caspase-3 in both wild-type and knockout mice. At 6-7 mm, there were fewer caspase-3(+) oligodendrocytes and astrocytes than at 3-4 mm. Importantly, caspase-3 activation was significantly lower in prodynorphin(-/-) oligodendrocytes and astrocytes, as compared with wild-type mice. In contrast, while caspase-3 expression in neurons also declined with further distance from the injury, there was no effect of genotype. Radioimmunoassay showed that dynorphin A(1-17) was regionally increased in wild-type injured versus sham-injured tissues, although levels of the prodynorphin processing product Arg(6)-Leu-enkephalin were unchanged. Our results indicate that dynorphin peptides affect the extent of post-injury caspase-3 activation, and that glia are especially sensitive to these effects. By promoting caspase-3 activation, dynorphin peptides likely increase the probability of glial apoptosis after SCI. While normally beneficial, our findings suggest that prodynorphin or its peptide products become maladaptive following SCI and contribute to secondary injury.
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Affiliation(s)
- V V Adjan
- Department of Anatomy and Neurobiology, 800 Rose Street, MS209, University of Kentucky, Lexington, KY 40536-0298, USA
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15
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Dasari VR, Spomar DG, Li L, Gujrati M, Rao JS, Dinh DH. Umbilical cord blood stem cell mediated downregulation of fas improves functional recovery of rats after spinal cord injury. Neurochem Res 2007; 33:134-49. [PMID: 17703359 PMCID: PMC2167626 DOI: 10.1007/s11064-007-9426-6] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2007] [Accepted: 06/22/2007] [Indexed: 01/09/2023]
Abstract
Human umbilical cord blood stem cells (hUCB), due to their primitive nature and ability to develop into nonhematopoietic cells of various tissue lineages, represent a potentially useful source for cell-based therapies after spinal cord injury (SCI). To evaluate their therapeutic potential, hUCB were stereotactically transplanted into the injury epicenter, one week after SCI in rats. Our results show the presence of a substantial number of surviving hUCB in the injured spinal cord up to five weeks after transplantation. Three weeks after SCI, apoptotic cells were found especially in the dorsal white matter and gray matter, which are positive for both neuron and oligodendrocyte markers. Expression of Fas on both neurons and oligodendrocytes was efficiently downregulated by hUCB. This ultimately resulted in downregulation of caspase-3 extrinsic pathway proteins involving increased expression of FLIP, XIAP and inhibition of PARP cleavage. In hUCB-treated rats, the PI3K/Akt pathway was also involved in antiapoptotic actions. Further, structural integrity of the cytoskeletal proteins alpha-tubulin, MAP2A&2B and NF-200 has been preserved in hUCB treatments. The behavioral scores of hind limbs of hUCB-treated rats improved significantly than those of the injured group, showing functional recovery. Taken together, our results indicate that hUCB-mediated downregulation of Fas and caspases leads to functional recovery of hind limbs of rats after SCI.
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Affiliation(s)
- Venkata Ramesh Dasari
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine, Peoria, IL 61656
| | - Daniel G. Spomar
- Department of Neurosurgery, University of Illinois College of Medicine at Peoria, Peoria, IL 61656
| | - Liang Li
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine, Peoria, IL 61656
| | - Meena Gujrati
- Department of Pathology, University of Illinois College of Medicine at Peoria, Peoria, IL 61656
| | - Jasti S. Rao
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine, Peoria, IL 61656
- Department of Neurosurgery, University of Illinois College of Medicine at Peoria, Peoria, IL 61656
| | - Dzung H. Dinh
- Department of Neurosurgery, University of Illinois College of Medicine at Peoria, Peoria, IL 61656
- *Corresponding Author: Dzung H. Dinh, M.D., Department of Neurosurgery, University of Illinois College of Medicine at Peoria, One Illini Drive, Peoria, IL 61605, USA, (309) 655-2642 – phone; (309) 655-7696 - fax; e-mail:
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Dasari VR, Spomar DG, Cady C, Gujrati M, Rao JS, Dinh DH. Mesenchymal stem cells from rat bone marrow downregulate caspase-3-mediated apoptotic pathway after spinal cord injury in rats. Neurochem Res 2007; 32:2080-93. [PMID: 17564836 PMCID: PMC2084491 DOI: 10.1007/s11064-007-9368-z] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Accepted: 04/27/2007] [Indexed: 02/06/2023]
Abstract
Mesenchymal stem cells have been intensively studied for their potential use in reparative strategies for neurodegenerative diseases and traumatic injuries. We used mesenchymal stem cells (rMSC) from rat bone marrow to evaluate the therapeutic potential after spinal cord injury (SCI). Immunohistochemistry confirmed a large number of apoptotic neurons and oligodendrocytes in caudal segments 2 mm away from the lesion site. Expression of caspase-3 on both neurons and oligodendrocytes after SCI was significantly downregulated by rMSC. Caspase-3 downregulation by rMSC involves increased expression of FLIP and XIAP in the cytosol and inhibition of PARP cleavage in the nucleus. Animals treated with rMSC had higher Basso, Beattie, Bresnahan (BBB) locomotor scoring and better recovery of hind limb sensitivity. Treatment with rMSC had a positive effect on behavioral outcome and histopathological assessment after SCI. The ability of rMSC to incorporate into the spinal cord, differentiate and to improve locomotor recovery hold promise for a potential cure after SCI.
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Affiliation(s)
- Venkata Ramesh Dasari
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine, Peoria, IL 61656
| | - Daniel G. Spomar
- Department of Neurosurgery, University of Illinois College of Medicine at Peoria, Peoria, IL 61656
| | - Craig Cady
- Department of Biology, Bradley University, Peoria, IL 61625
| | - Meena Gujrati
- Department of Pathology, University of Illinois College of Medicine at Peoria, Peoria, IL 61656
| | - Jasti S. Rao
- Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine, Peoria, IL 61656
- Department of Neurosurgery, University of Illinois College of Medicine at Peoria, Peoria, IL 61656
| | - Dzung H. Dinh
- Department of Neurosurgery, University of Illinois College of Medicine at Peoria, Peoria, IL 61656
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Acarin L, Villapol S, Faiz M, Rohn TT, Castellano B, González B. Caspase-3 activation in astrocytes following postnatal excitotoxic damage correlates with cytoskeletal remodeling but not with cell death or proliferation. Glia 2007; 55:954-65. [PMID: 17487878 DOI: 10.1002/glia.20518] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Caspase-3 has classically been defined as the main executioner of programmed cell death. However, recent data supports the participation of this protease in non-apoptotic cellular events including cell proliferation, cell cycle regulation, and cellular differentiation. In this study, astroglial cleavage of caspase-3 was analyzed following excitotoxic damage in postnatal rats to determine if its presence is associated with apoptotic cell death, cell proliferation, or cytoskeletal remodeling. A well-characterized in vivo model of excitotoxicity was studied, where damage was induced by intracortical injection of N-methyl-D-asparate (NMDA) in postnatal day 9 rats. Our results demonstrate that cleaved caspase-3 was mainly observed in the nucleus of activated astrocytes in the lesioned hemisphere as early as 4 h postlesion and persisted until the glial scar was formed at 7-14 days, and it was not associated with TUNEL labeling. Caspase-3 enzymatic activity was detected at 10 h and 1 day postlesion in astrocytes, and co-localized with caspase-cleaved fragments of glial fibrillary acidic protein (CCP-GFAP). However, at longer survival times, when astroglial hypertrophy was observed, astroglial caspase-3 did not generally correlate with GFAP cleavage, but instead was associated with de novo expression of vimentin. Moreover, astroglial caspase-3 cleavage was not associated with BrdU incorporation. These results provide further evidence for a nontraditional role of caspases in cellular function that is independent of cell death and suggest that caspase activation is important for astroglial cytoskeleton remodeling following cellular injury.
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Affiliation(s)
- Laia Acarin
- Medical Histology, Department of Cell Biology, Physiology and Immunology, Faculty of Medicine and Institute of Neurosciences, Autonomous University of Barcelona, Spain.
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Onifer SM, Rabchevsky AG, Scheff SW. Rat Models of Traumatic Spinal Cord Injury to Assess Motor Recovery. ILAR J 2007; 48:385-95. [PMID: 17712224 DOI: 10.1093/ilar.48.4.385] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Devastating motor, sensory, and autonomic dysfunctions render long-term personal hardships to the survivors of traumatic spinal cord injury (SCI). The suffering also extends to the survivors' families and friends, who endure emotional, physical, and financial burdens in providing for necessary surgeries, care, and rehabilitation. After the primary mechanical SCI, there is a complex secondary injury cascade that leads to the progressive death of otherwise potentially viable axons and cells and that impairs endogenous recovery processes. Investigations of possible cures and of ways to alleviate the hardships of traumatic SCI include those of interventions that attenuate or overcome the secondary injury cascade, enhance the endogenous repair mechanisms, regenerate axons, replace lost cells, and rehabilitate. These investigations have led to the creation of laboratory animal models of the different types of traumatic human SCI and components of the secondary injury cascade. However, no particular model completely addresses all aspects of traumatic SCI. In this article, we describe adult rat SCI models and the motor, and in some cases sensory and autonomic, deficits that each produces. Importantly, as researchers in this area move toward clinical trials to alleviate the hardships of traumatic SCI, there is a need for standardized small and large animal SCI models as well as quantitative behavioral and electrophysiological assessments of their outcomes so that investigators testing various interventions can directly compare their results and correlate them with the molecular, biochemical, and histological alterations.
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Affiliation(s)
- Stephen M Onifer
- Spinal Cord and Brain Injury Research Center, Biomedical and Biological Sciences Research Building, University of Kentucky, 741 South Limestone Street, Lexington, KY 40536-0509, USA.
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Solaroglu I, Kaptanoglu E, Okutan O, Beskonakli E, Attar A, Kilinc K. Magnesium sulfate treatment decreases caspase-3 activity after experimental spinal cord injury in rats. ACTA ACUST UNITED AC 2005; 64 Suppl 2:S17-21. [PMID: 16256834 DOI: 10.1016/j.surneu.2005.07.058] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2005] [Indexed: 12/15/2022]
Abstract
BACKGROUND Apoptosis has increasingly been considered as an important factor in secondary injury after spinal cord injury (SCI). Manifestation of apoptotic cell death process involves activation of the caspase-3 apoptotic cascade. The aim of the study was to demonstrate the effect of magnesium sulfate on caspase-3 activity and to compare its effectiveness with methylprednisolone after acute SCI. METHODS The rats were randomly and blindly allocated into 5 groups of 8 rats each. Spinal cord contusion injury was produced by the weight drop method. The control group consisted of non-injured rats. In the trauma group, no treatment was given, whereas 1 mL saline, 600 mg/kg magnesium sulfate, and 30 mg/kg methylprednisolone sodium succinate (MPSS) were administered in the vehicle and both treatment groups immediately after injury. Twenty-four hours after trauma, spinal cord samples were obtained, and tissue caspase-3 activity levels were examined. A 1-way analysis of variance and the post hoc test were used for statistical analysis. RESULTS The results showed that caspase-3 activity increased to statistically significantly higher levels in spinal cord after contusion injury than in the control group. Caspase-3 enzyme activity levels were significantly reduced in animals treated either with magnesium sulfate or MPSS. CONCLUSIONS We have shown that magnesium sulfate decreases caspase-3 activity in rat spinal cord subjected to contusion injury. Magnesium sulfate may have potential therapeutic benefits by reducing apoptotic tissue damage after SCI.
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Affiliation(s)
- Ihsan Solaroglu
- Department of Neurological Surgery, Ankara Ataturk Research and Education Hospital, Ankara 06100, Turkey
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Knoblach SM, Huang X, VanGelderen J, Calva-Cerqueira D, Faden AI. Selective caspase activation may contribute to neurological dysfunction after experimental spinal cord trauma. J Neurosci Res 2005; 80:369-80. [PMID: 15795935 DOI: 10.1002/jnr.20465] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Caspases are implicated in apoptotic cell death after spinal cord injury (SCI), but the relative contribution of these proteases to the secondary injury process has been only partially described. We examined the activation of caspases 1, 2, 3, 6, 8, and 9 from 1 hr to 7 days after moderate contusion injury induced by a weight-drop method in the rat. Tissue homogenates from a 1-cm segment of cord that contained the site of impact were processed by fluorometric enzymatic activity assays and/or immunoblotting methods. Caspases 3, 8, and 9 were activated from 1 to 72 hr after injury, whereas caspases 1, 2, and 6 were not. Double-label immunohistochemistry utilizing antibodies for CNS cell-type-specific markers and active subunits of caspases 3, 8, or 9 showed that, at 4 and 72 hr after injury, these caspases were primarily activated in neurons and oligodendrocytes, rather than in astrocytes. Active caspase subunits were present in neurons within the necrotic lesion core at 4 hr after injury and in cells more than several segments away at 4 or 72 hr after injury. Intrathecal injection of the pan-caspase inhibitor Boc-Asp (OMe)-fluoromethylketone (Boc-d-fmk) at 15 min after injury improved locomotor function 21 and 28 days later. Treatment with the selective caspase 3 inhibitor N-benzyloxycarbonyl-Asp-Glu-Val-Asp-fluoromethyl ketone (z-DEVD-fmk) improved function at 21 days after injury. These data suggest that caspases 3, 8, and 9 may be differentially activated in white and gray matter after spinal cord trauma and that such activation may contribute to subsequent neurological dysfunction.
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Affiliation(s)
- S M Knoblach
- Department of Neuroscience, Georgetown University Medical Center, Washington, DC 20007, USA.
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Xu W, Chi L, Xu R, Ke Y, Luo C, Cai J, Qiu M, Gozal D, Liu R. Increased production of reactive oxygen species contributes to motor neuron death in a compression mouse model of spinal cord injury. Spinal Cord 2005; 43:204-13. [PMID: 15520836 DOI: 10.1038/sj.sc.3101674] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
STUDY DESIGN Experimental laboratory investigation of the role and pathways of reactive oxygen species (ROS)-mediated motor neuron cell death in a mouse model of compression spinal cord injury. OBJECTIVES To analyze ROS-mediated oxidative stress propagation and signal transduction leading to motor neuron apoptosis induced by compression spinal cord injury. SETTING University of Louisville Health Science Center. METHODS Adult C57BL/6J mice and transgenic mice overexpressing SOD1 were severely lesioned at the lumbar region by compression spinal cord injury approach. Fluorescent oxidation, oxidative response gene expression and oxidative stress damage markers were used to assay spinal cord injury-mediated ROS generation and oxidative stress propagation. Biochemical and immunohistochemical analyses were applied to define the ROS-mediated motor neuron apoptosis resulted from compression spinal cord injury. RESULTS ROS production was shown to be elevated in the lesioned spinal cord as detected by fluorescent oxidation assays. The early oxidative stress response markers, NF-kappaB transcriptional activation and c-Fos gene expression, were significantly increased after spinal cord injury. Lipid peroxidation and nucleic acid oxidation were also elevated in the lesioned spinal cord and motor neurons. Cytochrome c release, caspase-3 activation and apoptotic cell death were increased in the spinal cord motor neuron cells after spinal cord injury. On the other hand, transgenic mice overexpressing SOD1 showed lower levels of steady-state ROS production and reduction of motor neuron apoptosis compared to that of control mice after spinal cord injury. CONCLUSION These data together provide direct evidence to demonstrate that the increased production of ROS is an early and likely causal event that contributes to the spinal cord motor neuron death following spinal cord injury. Thus, antioxidants/antioxidant enzyme intervention combined with other therapy may provide an effective approach to alleviate spinal cord injury-induced motor neuron damage and motor dysfunction.
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Affiliation(s)
- W Xu
- Department of Pediatrics, Kosair Children's Hospital Research Institute, University of Louisville, Louisville, KY 40202, USA
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Rosenzweig ES, McDonald JW. Rodent models for treatment of spinal cord injury: research trends and progress toward useful repair. Curr Opin Neurol 2004; 17:121-31. [PMID: 15021237 DOI: 10.1097/00019052-200404000-00007] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
PURPOSE OF REVIEW In this review, we have documented some current research trends in rodent models of spinal cord injury. We have also catalogued the treatments used in studies published between October 2002 and November 2003, with special attention given to studies in which treatments were delayed for at least 4 days after injury. RECENT FINDINGS Most spinal cord injury studies are performed with one of three general injury models: transection, compression, or contusion. Although most treatments are begun immediately after injury, a growing number of studies have used delayed interventions. Mice and the genetic tools they offer are gaining in popularity. Some researchers are setting their sights beyond locomotion, to issues more pressing for people with spinal cord injury (especially bladder function and pain). SUMMARY Delayed treatment protocols may extend the window of opportunity for treatment of spinal cord injury, whereas continued progress in the prevention of secondary cell death will reduce the severity of new cases. The use of mice will hopefully accelerate progress towards useful regeneration in humans. Researchers must improve cross-study comparability to allow balanced decisions about potentially useful treatments.
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Affiliation(s)
- Ephron S Rosenzweig
- Department of Neurology, Washington University School of Medicine, St Louis, Missouri, USA.
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