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Liu Z, Tu K, Zou P, Liao C, Ding R, Huang Z, Huang Z, Yao X, Chen J, Zhang Z. Hesperetin ameliorates spinal cord injury by inhibiting NLRP3 inflammasome activation and pyroptosis through enhancing Nrf2 signaling. Int Immunopharmacol 2023; 118:110103. [PMID: 37001385 DOI: 10.1016/j.intimp.2023.110103] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 03/08/2023] [Accepted: 03/24/2023] [Indexed: 03/30/2023]
Abstract
Neuroinflammation is a prominent feature of traumatic spinal cord injuries (SCIs). Hesperetin exhibits anti-inflammatory effects in neurological disorders; however, the potential neuroprotective effects of hesperetin in cases of SCI remain unclear. Sprague-Dawley rats with C5 hemi-contusion injuries were used as an SCI model. Hesperetin was administered to the experimental rats in order to investigate its neuroprotective effects after SCI, and BV2 cells were pretreated with hesperetin or silencing of nuclear factor erythroid 2-related factor 2 (siNrf2), and then stimulated with lipopolysaccharide (LPS) and adenosine triphosphate (ATP). The therapeutic impact and molecular mechanism of hesperetin were elucidated in a series of in vivo and in vitro investigations conducted using a combination of experiments. The results of the present in vivo experiment indicated that hesperetin improved functional recovery and protected spinal cord tissue after SCI. Hesperetin attenuated oxidative stress and microglial activation, lowered malondialdehyde (MDA) levels, and elevated catalase (CAT), glutathione (GSH)-Px, and superoxide dismutase (SOD) levels. Moreover, hesperetin downregulated the expression of advanced oxygenation protein products (AOPPs), ionized calcium-binding adapter molecule 1 (Iba-1), NOD-like receptor protein 3 (NLRP3), and interleukin-1 beta (IL-1β), but increased the expression of Nrf2. In vitro studies have shown that hesperetin inhibits the generation of reactive oxygen species (ROS), as well as the neuroinflammation associated with the upregulation of Nrf2 and heme oxygenase-1 (HO-1) in BV2 cells. The results of the present study indicated that hesperetin inhibited BV2 cell pyroptosis and significantly blocked the expression of NLRP3 inflammasome proteins (NLRP3 Caspase-1 p10 apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain [ASC]) and pro-inflammatory mediators (IL-18, IL-1β). Furthermore, the silencing of Nrf2 by small interfering ribonucleic acid (siRNA) partially abolished its antioxidant effect in the aforementioned cell experiments. Collectively, these findings illustrate that through an increase in Nrf2 signaling hesperetin reduces oxidative stress and neuroinflammation by suppressing NLRP3 inflammasome activation and pyroptosis.
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Kjell J, Svensson M. Advancing Peripheral Nerve Graft Transplantation for Incomplete Spinal Cord Injury Repair. Front Cell Neurosci 2022; 16:885245. [PMID: 35573831 PMCID: PMC9097274 DOI: 10.3389/fncel.2022.885245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Accepted: 04/06/2022] [Indexed: 11/13/2022] Open
Abstract
Peripheral nerves have a propensity for axon growth and regeneration that the central nervous system lacks (CNS). However, CNS axons can also grow long distances if introduced to a graft harvested from a peripheral nerve (PNGs), which is the rationale for using PNGs as repair strategy for injuries of the spinal cord. From a clinical perspective, PNGs provide interesting possibilities with potential to repair the injured spinal cord. First, there are numerous options to harvest autologous grafts associated with low risk for the patient. Second, a PNG allow axons to grow considerable distances and can, by the surgical procedure, be navigated to specific target sites in the CNS. Furthermore, a PNG provides all necessary biological substrates for myelination of elongating axons. A PNG can thus be suited to bridge axons long distances across an injury site and restore long tracts in incomplete SCI. Experimentally, locomotor functions have been improved transplanting a PNG after incomplete injury. However, we still know little with regard to the formation of new circuitries and functional outcome in association to when, where, and how grafts are inserted into the injured spinal cord, especially for sensory functions. In this perspective, we discuss the advantages of PNG from a clinical and surgical perspective, the need for adding/repairing long tracts, how PNGs are best applied for incomplete injuries, and the unexplored areas we believe are in need of answers.
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Affiliation(s)
- Jacob Kjell
- Department of Clinical Neuroscience, Karolinska Institutet, Solna, Sweden
| | - Mikael Svensson
- Department of Clinical Neuroscience, Karolinska Institutet, Solna, Sweden
- Neurosurgery, Karolinska University Hospital, Solna, Sweden
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Wang P, Yin R, Wang S, Zhou T, Zhang Y, Xiao M, Wang H, Xu G. Effects of Repetitive Transcranial Magnetic Stimulation (rTMS) and Treadmill Training on Recovery of Motor Function in a Rat Model of Partial Spinal Cord Injury. Med Sci Monit 2021; 27:e931601. [PMID: 34304239 PMCID: PMC8317583 DOI: 10.12659/msm.931601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Background This study aimed to investigate the effects of repetitive transcranial magnetic stimulation (rTMS) and treadmill training (TT) on motor function recovery in rats with partial spinal cord injury (SCI). Material/Methods Sixty rats with moderate partial SCI at the 9th thoracic vertebral level induced by a Louisville Injury System Apparatus impactor were randomly allocated to 5 groups: Sham surgery (Intact); Sham rTMS without TT (S-rTMS/Non-TT); Sham rTMS with TT (S-rTMS/TT); rTMS without TT (rTMS/Non-TT); and rTMS with TT (rTMS/TT). Interventions commenced 8 days after SCI and continued for 8 weeks. Outcomes studied were Basso, Beattie, and Bresnahan locomotor scale scores, grid walking test, and biochemical analysis of the brain-derived neurotrophic factor (BDNF), synapsin I (SYN), and postsynaptic density protein-95 (PSD-95) in the motor cortex and spinal cord. Results The rTMS/TT contributed to greater Basso, Beattie, and Bresnahan scores compared with the S-rTMS/Non-TT (P<0.01), S-rTMS/TT (P<0.05), and rTMS/Non-TT (P<0.05), and showed obviously reduced numbers of foot drops compared with the S-rTMS/Non-TT (P<0.05). The rTMS/TT significantly increased the expressions of BDNF, SYN, and PSD-95 compared with the S-rTMS/Non-TT, both in the motor cortex (P<0.01, P<0.01, P<0.001, respectively) and spinal cord (P<0.001, P<0.01, P<0.05, respectively). Conclusions In a modified rat model of SCI, combined rTMS with TT improved motor function, indicating that this combined approach promoted adaptive neuroplasticity between the motor cortex and the spinal cord. A combined app roach to improving motor function following SCI requires further evaluation to determine the possible clinical applications.
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Affiliation(s)
- Pei Wang
- School of Rehabilitation Medicine, Nanjing Medical University, Center of Rehabilitation Medicine, 1st affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China (mainland).,Department of Rehabilitation Medicine, Jiangsu Shengze Hospital, Nanjing Medical University, Suzhou, Jiangsu, China (mainland)
| | - Ruian Yin
- School of Rehabilitation Medicine, Nanjing Medical University, Center of Rehabilitation Medicine, 1st affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China (mainland)
| | - Shuangyan Wang
- School of Rehabilitation Medicine, Nanjing Medical University, Center of Rehabilitation Medicine, 1st affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China (mainland)
| | - Ting Zhou
- Department of Rehabilitation Medicine, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, China (mainland)
| | - Yongjie Zhang
- Department of Human Anatomy, Nanjing Medical University, Nanjing, Jiangsu, China (mainland)
| | - Ming Xiao
- Jiangsu Key Laboratory of Neurodegeneration, Nanjing Medical University, Nanjing, Jiangsu, China (mainland)
| | - Hongxing Wang
- Department of Rehabilitation Medicine, Jiangsu Shengze Hospital, Nanjing Medical University, Suzhou, Jiangsu, China (mainland).,Department of Rehabilitation Medicine, Zhongda Hospital, School of Medicine, Southeast University, Nanjing, Jiangsu, China (mainland)
| | - Guangxu Xu
- School of Rehabilitation Medicine, Nanjing Medical University, Center of Rehabilitation Medicine, 1st affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China (mainland)
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Cheng L, Sami A, Ghosh B, Goudsward HJ, Smith GM, Wright MC, Li S, Lepore AC. Respiratory axon regeneration in the chronically injured spinal cord. Neurobiol Dis 2021; 155:105389. [PMID: 33975016 DOI: 10.1016/j.nbd.2021.105389] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 04/19/2021] [Accepted: 05/05/2021] [Indexed: 02/01/2023] Open
Abstract
Promoting the combination of robust regeneration of damaged axons and synaptic reconnection of these growing axon populations with appropriate neuronal targets represents a major therapeutic goal following spinal cord injury (SCI). A key impediment to achieving this important aim includes an intrinsic inability of neurons to extend axons in adult CNS, particularly in the context of the chronically-injured spinal cord. We tested whether an inhibitory peptide directed against phosphatase and tensin homolog (PTEN: a central inhibitor of neuron-intrinsic axon growth potential) could restore inspiratory diaphragm function by reconnecting critical respiratory neural circuitry in a rat model of chronic cervical level 2 (C2) hemisection SCI. We found that systemic delivery of PTEN antagonist peptide 4 (PAP4) starting at 8 weeks after C2 hemisection promoted substantial, long-distance regeneration of injured bulbospinal rostral Ventral Respiratory Group (rVRG) axons into and through the lesion and back toward phrenic motor neurons (PhMNs) located in intact caudal C3-C5 spinal cord. Despite this robust rVRG axon regeneration, PAP4 stimulated only minimal recovery of diaphragm function. Furthermore, re-lesion through the hemisection site completely removed PAP4-induced functional improvement, demonstrating that axon regeneration through the lesion was responsible for this partial functional recovery. Interestingly, there was minimal formation of putative excitatory monosynaptic connections between regrowing rVRG axons and PhMN targets, suggesting that (1) limited rVRG-PhMN synaptic reconnectivity was responsible at least in part for the lack of a significant functional effect, (2) chronically-injured spinal cord presents an obstacle to achieving synaptogenesis between regenerating axons and post-synaptic targets, and (3) addressing this challenge is a potentially-powerful strategy to enhance therapeutic efficacy in the chronic SCI setting. In conclusion, our study demonstrates a non-invasive and transient pharmacological approach in chronic SCI to repair the critically-important neural circuitry controlling diaphragmatic respiratory function, but also sheds light on obstacles to circuit plasticity presented by the chronically-injured spinal cord.
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Affiliation(s)
- Lan Cheng
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Armin Sami
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Biswarup Ghosh
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Hannah J Goudsward
- Department of Biology, Arcadia University, 450 S. Easton Rd., 220 Boyer Hall, Glenside, PA 19038, USA
| | - George M Smith
- Department of Neuroscience, Shriners Hospitals for Pediatric Research Center, Temple University School of Medicine, 3500 North Broad Street, Philadelphia, PA 19140-5104, USA
| | - Megan C Wright
- Department of Biology, Arcadia University, 450 S. Easton Rd., 220 Boyer Hall, Glenside, PA 19038, USA
| | - Shuxin Li
- Department of Neuroscience, Shriners Hospitals for Pediatric Research Center, Temple University School of Medicine, 3500 North Broad Street, Philadelphia, PA 19140-5104, USA
| | - Angelo C Lepore
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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Liu ZH, Huang YC, Kuo CY, Kuo CY, Chin CY, Yip PK, Chen JP. Docosahexaenoic Acid-Loaded Polylactic Acid Core-Shell Nanofiber Membranes for Regenerative Medicine after Spinal Cord Injury: In Vitro and In Vivo Study. Int J Mol Sci 2020; 21:ijms21197031. [PMID: 32987768 PMCID: PMC7583922 DOI: 10.3390/ijms21197031] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 09/22/2020] [Accepted: 09/23/2020] [Indexed: 12/13/2022] Open
Abstract
Spinal cord injury (SCI) is associated with disability and a drastic decrease in quality of life for affected individuals. Previous studies support the idea that docosahexaenoic acid (DHA)-based pharmacological approach is a promising therapeutic strategy for the management of acute SCI. We postulated that a nanostructured material for controlled delivery of DHA at the lesion site may be well suited for this purpose. Toward this end, we prepare drug-loaded fibrous mats made of core-shell nanofibers by electrospinning, which contained a polylactic acid (PLA) shell for encapsulation of DHA within the core, for delivery of DHA in situ. In vitro study confirmed sustained DHA release from PLA/DHA core-shell nanofiber membrane (CSNM) for up to 36 days, which could significantly increase neurite outgrowth from primary cortical neurons in 3 days. This is supported by the upregulation of brain-derived neurotropic factor (BDNF) and neurotrophin-3 (NT-3) neural marker genes from qRT-PCR analysis. Most importantly, the sustained release of DHA could significantly increase the neurite outgrowth length from cortical neuron cells in 7 days when co-cultured with PLA/DHA CSNM, compared with cells cultured with 3 μM DHA. From in vivo study with a SCI model created in rats, implantation of PLA/DHA CSNM could significantly improve neurological functions revealed by behavior assessment in comparison with the control (no treatment) and the PLA CSNM groups. According to histological analysis, PLA/DHA CSNM also effectively reduced neuron loss and increased serotonergic nerve sprouting. Taken together, the PLA/DHA CSNM may provide a nanostructured drug delivery system for DHA and contribute to neuroprotection and promoting neuroplasticity change following SCI.
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Affiliation(s)
- Zhuo-Hao Liu
- Department of Neurosurgery, Chang Gung Memorial Hospital, Linkou, Chang Gung University School of Medicine, Kwei-San, Taoyuan 33305, Taiwan; (Z.-H.L.); (Y.-C.H.); (C.-Y.K.); (C.-Y.C.)
| | - Yin-Cheng Huang
- Department of Neurosurgery, Chang Gung Memorial Hospital, Linkou, Chang Gung University School of Medicine, Kwei-San, Taoyuan 33305, Taiwan; (Z.-H.L.); (Y.-C.H.); (C.-Y.K.); (C.-Y.C.)
| | - Chang-Yi Kuo
- Department of Chemical and Materials and Materials Engineering, Chang Gung University, Kwei-San, Taoyuan 33302, Taiwan;
| | - Chao-Ying Kuo
- Department of Neurosurgery, Chang Gung Memorial Hospital, Linkou, Chang Gung University School of Medicine, Kwei-San, Taoyuan 33305, Taiwan; (Z.-H.L.); (Y.-C.H.); (C.-Y.K.); (C.-Y.C.)
| | - Chieh-Yu Chin
- Department of Neurosurgery, Chang Gung Memorial Hospital, Linkou, Chang Gung University School of Medicine, Kwei-San, Taoyuan 33305, Taiwan; (Z.-H.L.); (Y.-C.H.); (C.-Y.K.); (C.-Y.C.)
| | - Ping K. Yip
- Queen Mary University of London, Barts and The London School of Medicine and Dentistry, Blizard Institute, Centre for Neuroscience, Surgery & Trauma, London E1 2AT, UK;
| | - Jyh-Ping Chen
- Department of Chemical and Materials and Materials Engineering, Chang Gung University, Kwei-San, Taoyuan 33302, Taiwan;
- Department of Plastic and Reconstructive Surgery and Craniofacial Research Center, Chang Gung Memorial Hospital, Linkou, Kwei-San, Taoyuan 33305, Taiwan
- Research Center for Food and Cosmetic Safety, Research Center for Chinese Herbal Medicine, College of Human Ecology, Chang Gung University of Science and Technology, Taoyuan 33302, Taiwan
- Department of Materials Engineering, Ming Chi University of Technology, Tai-Shan, New Taipei City 24301, Taiwan
- Correspondence: ; Tel.: +886-3211-8800 (ext. 5298)
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Liu Z, Yao X, Jiang W, Li W, Zhu S, Liao C, Zou L, Ding R, Chen J. Advanced oxidation protein products induce microglia-mediated neuroinflammation via MAPKs-NF-κB signaling pathway and pyroptosis after secondary spinal cord injury. J Neuroinflammation 2020; 17:90. [PMID: 32192500 PMCID: PMC7082940 DOI: 10.1186/s12974-020-01751-2] [Citation(s) in RCA: 174] [Impact Index Per Article: 43.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 02/20/2020] [Indexed: 12/20/2022] Open
Abstract
Background Inflammatory response mediated by oxidative stress is considered as an important pathogenesis of spinal cord injury (SCI). Advanced oxidation protein products (AOPPs) are novel markers of oxidative stress and their role in inflammatory response after SCI remained unclear. This study aimed to investigate the role of AOPPs in SCI pathogenesis and explore the possible underlying mechanisms. Methods A C5 hemi-contusion injury was induced in Sprague-Dawley rats to confirm the involvement of AOPPs after SCI. For in vivo study, apocynin, the NADPH oxidase inhibitor was used to study the neuroprotective effects after SCI. For in vitro study, the BV2 microglia cell lines were pretreated with or without the inhibitor or transfected with or without small interference RNA (siRNA) and then stimulated with AOPPs. A combination of molecular and histological methods was used to clarify the mechanism and explore the signaling pathway both in vivo and in vitro. One-way analysis of variance (ANOVA) was conducted with Bonferroni post hoc tests to examine the differences between groups. Results The levels of AOPPs in plasma and cerebrospinal fluid as well as the contents in the spinal cord showed significant increase after SCI. Meanwhile, apocynin ameliorated tissue damage in the spinal cord after SCI, improving the functional recovery. Immunofluorescence staining and western blot analysis showed activation of microglia after SCI, which was in turn inhibited by apocynin. Pretreated BV2 cells with AOPPs triggered excessive generation of reactive oxygen species (ROS) by activating NADPH oxidase. Increased ROS induced p38 MAPK and JNK phosphorylation, subsequently triggering nuclear translocation of NF-κB p65 to express pro-inflammatory cytokines. Also, treatment of BV2 cells with AOPPs induced NLRP3 inflammasome activation and cleavage of Gasdermin-d (GSDMD), causing pyroptosis. This was confirmed by cleavage of caspase-1, production of downstream mature interleukin (IL)-1β and IL-18 as well as rupture of rapid cell membrane. Conclusions Collectively, these data indicated AOPPs as biomarkers of oxidative stress, modulating inflammatory response in SCI by multiple signaling pathways, which also included the induction of NADPH oxidase dependent ROS, and NLRP3-mediated pyroptosis, and activation of MAPKs and NF-κB.
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Affiliation(s)
- Zhongyuan Liu
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, Guangdong, China
| | - Xinqiang Yao
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, Guangdong, China
| | - Wangsheng Jiang
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, Guangdong, China
| | - Wei Li
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, Guangdong, China
| | - Siyuan Zhu
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, Guangdong, China
| | - Congrui Liao
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, Guangdong, China
| | - Lin Zou
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, Guangdong, China
| | - Ruoting Ding
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, Guangdong, China.
| | - Jianting Chen
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, Guangdong, China.
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Verma R, Virdi JK, Singh N, Jaggi AS. Animals models of spinal cord contusion injury. Korean J Pain 2019; 32:12-21. [PMID: 30671199 PMCID: PMC6333579 DOI: 10.3344/kjp.2019.32.1.12] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 11/30/2018] [Accepted: 12/01/2018] [Indexed: 12/03/2022] Open
Abstract
Spinal cord contusion injury is one of the most serious nervous system disorders, characterized by high morbidity and disability. To mimic spinal cord contusion in humans, various animal models of spinal contusion injury have been developed. These models have been developed in rats, mice, and monkeys. However, most of these models are developed using rats. Two types of animal models, i.e. bilateral contusion injury and unilateral contusion injury models, are developed using either a weight drop method or impactor method. In the weight drop method, a specific weight or a rod, having a specific weight and diameter, is dropped from a specific height on to the exposed spinal cord. Low intensity injury is produced by dropping a 5 g weight from a height of 8 cm, moderate injury by dropping 10 g weight from a height of 12.5–25 mm, and high intensity injury by dropping a 25 g weight from a height of 50 mm. In the impactor method, injury is produced through an impactor by delivering a specific force to the exposed spinal cord area. Mild injury is produced by delivering 100 ± 5 kdyn of force, moderate injury by delivering 200 ± 10 kdyn of force, and severe injury by delivering 300 ± 10 kdyn of force. The contusion injury produces a significant development of locomotor dysfunction, which is generally evident from the 0–14th day of surgery and is at its peak after the 28–56th day. The present review discusses different animal models of spinal contusion injury.
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Affiliation(s)
- Renuka Verma
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University Patiala, Patiala, India
| | - Jasleen Kaur Virdi
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University Patiala, Patiala, India
| | - Nirmal Singh
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University Patiala, Patiala, India
| | - Amteshwar Singh Jaggi
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University Patiala, Patiala, India
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Lujan HL, Tonson A, Wiseman RW, DiCarlo SE. Chronic, complete cervical 6-7 cord transection: distinct autonomic and cardiac deficits. J Appl Physiol (1985) 2018; 124:1471-1482. [PMID: 29470149 DOI: 10.1152/japplphysiol.01104.2017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Spinal cord injury (SCI) resulting in tetraplegia is a devastating, life-changing insult causing paralysis and sensory impairment as well as distinct autonomic dysfunction that triggers compromised cardiovascular, bowel, bladder, and sexual activity. Life becomes a battle for independence as even routine bodily functions and the smallest activity of daily living become major challenges. Accordingly, there is a critical need for a chronic preclinical model of tetraplegia. This report addresses this critical need by comparing, for the first time, resting-, reflex-, and stress-induced cardiovascular, autonomic, and hormonal responses each week for 4 wk in 12 sham-operated intact rats and 12 rats with chronic, complete C6-7 spinal cord transection. Loss of supraspinal control to all sympathetic preganglionic neurons projecting to the heart and vasculature resulted in a profound bradycardia and hypotension, reduced cardiac sympathetic and parasympathetic tonus, reduced reflex- and stress-induced sympathetic responses, and reduced sympathetic support of blood pressure as well as enhanced reliance on angiotensin to maintain arterial blood pressure. Histological examination of the nucleus ambiguus and stellate ganglia supports the profound and distinct autonomic and cardiac deficits and reliance on angiotensin to maintain cardiovascular stability following chronic, complete cervical6-7 cord transection. NEW & NOTEWORTHY For the first time, resting-, reflex-, and stress-induced cardiovascular, autonomic, and hormonal responses were studied in rats with chronic, complete C6-7 cord transection. Loss of supraspinal control of all sympathetic preganglionic neurons reduced cardiac sympathetic and parasympathetic tonus, reflex and stress-induced sympathetic responses, and sympathetic support of blood pressure as well as enhanced reliance on angiotensin to maintain arterial blood pressure. Histological examination supports the distinct deficits associated with cervical cord injury.
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Affiliation(s)
- Heidi L Lujan
- Department of Physiology, Michigan State University College of Osteopathic Medicine , East Lansing, Michigan
| | - Anne Tonson
- Department of Physiology, Michigan State University College of Osteopathic Medicine , East Lansing, Michigan
| | - Robert W Wiseman
- Department of Physiology, Michigan State University College of Osteopathic Medicine , East Lansing, Michigan
| | - Stephen E DiCarlo
- Department of Physiology, Michigan State University College of Osteopathic Medicine , East Lansing, Michigan
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Palm vitamin E reduces locomotor dysfunction and morphological changes induced by spinal cord injury and protects against oxidative damage. Sci Rep 2017; 7:14365. [PMID: 29085045 PMCID: PMC5662565 DOI: 10.1038/s41598-017-14765-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 10/16/2017] [Indexed: 12/22/2022] Open
Abstract
Spinal cord injury (SCI) occurs following different types of crushes. External and internal outcomes of SCI are including paralysis, cavity, and cyst formation. Effects of dietary derived antioxidants, such as palm vitamin E on central nervous system (CNS) encourage researchers to focus on the potential therapeutic benefits of antioxidant supplements. In the present study, experiments were carried out to evaluate the neuro-protective effect of the palm vitamin E on locomotor function and morphological damages induced SCI. Seventy-two male rats (Sprague-Dawley) were randomly divided into four groups: sham (laminectomy); control (supplemented with the palm vitamin E at a dose of 100 mg/kg/day); untreated-SCI (partial crush, 30–33% for 20 sec); treated-SCI (partial crush, 30–33% for 20 sec supplemented with the palm vitamin E at a dose of 100 mg/kg/day). The treatment with the palm vitamin E significantly improved the hind limb locomotor function, reduced the histopathological changes and the morphological damage in the spinal cord. Also, the palm vitamin E indicated a statistically significant decrease in the oxidative damage indicators, malondialdehyde (MDA) level and glutathione peroxidase (GPx) activity in the treated-SCI compared to the untreated-SCI.
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Hou S, Saltos TM, Iredia IW, Tom VJ. Surgical techniques influence local environment of injured spinal cord and cause various grafted cell survival and integration. J Neurosci Methods 2017; 293:144-150. [PMID: 28947264 DOI: 10.1016/j.jneumeth.2017.09.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 09/20/2017] [Accepted: 09/21/2017] [Indexed: 12/19/2022]
Abstract
BACKGROUND Cellular transplantation to repair a complete spinal cord injury (SCI) is tremendously challenging due to the adverse local milieu for graft survival and growth. Results from cell transplantation studies yield great variability, which may possibly be due to the surgical techniques employed to induce an SCI. In order to delineate the influence of surgery on such inconsistency, we compared lesion morphology and graft survival as well as integration from different lesion methodologies of SCI. NEW METHOD Surgical techniques, including a traditional approach cut+microaspiration, and two new approaches, cut alone as well as crush, were employed to produce a complete SCI, respectively. Approximately half of the rats in each group received injury only, whereas the other half received grafts of fetal brainstem cells into the lesion gap. RESULTS Eight weeks after injury with or without graft, histological analysis showed that the cut+microaspiration surgery resulted in larger lesion cavities and severe fibrotic scars surrounding the cavity, and cellular transplants rarely formed a tissue bridge to penetrate the barrier. In contrast, the majority of cases treated with cut alone or crush exhibited smaller cavities and less scarring; the grafts expanded and blended extensively with the host tissue, which often built continuous tissue bridging the rostral and caudal cords. COMPARISON WITH EXISTING METHODS Scarring and cavitation were significantly reduced when microaspiration was avoided in SCI surgery, facilitating graft/host tissue fusion for signal transmission. CONCLUSION The result suggests that microaspiration frequently causes severe scars and cavities, thus impeding graft survival and integration.
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Affiliation(s)
- Shaoping Hou
- Spinal Cord Research Center, Department of Neurobiology & Anatomy, Drexel University College of Medicine, Philadelphia, PA, 19129, United States.
| | - Tatiana M Saltos
- Spinal Cord Research Center, Department of Neurobiology & Anatomy, Drexel University College of Medicine, Philadelphia, PA, 19129, United States
| | - Idiata W Iredia
- Spinal Cord Research Center, Department of Neurobiology & Anatomy, Drexel University College of Medicine, Philadelphia, PA, 19129, United States
| | - Veronica J Tom
- Spinal Cord Research Center, Department of Neurobiology & Anatomy, Drexel University College of Medicine, Philadelphia, PA, 19129, United States
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Shultz RB, Wang Z, Nong J, Zhang Z, Zhong Y. Local delivery of thyroid hormone enhances oligodendrogenesis and myelination after spinal cord injury. J Neural Eng 2017; 14:036014. [PMID: 28358726 DOI: 10.1088/1741-2552/aa6450] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Traumatic spinal cord injury (SCI) causes apoptosis of myelin-forming oligodendrocytes (OLs) and demyelination of surviving axons, resulting in conduction failure. Remyelination of surviving denuded axons provides a promising therapeutic target for spinal cord repair. While cell transplantation has demonstrated efficacy in promoting remyelination and functional recovery, the lack of ideal cell sources presents a major obstacle to clinical application. The adult spinal cord contains oligodendrocyte precursor cells and multipotent neural stem/progenitor cells that have the capacity to differentiate into mature, myelinating OLs. However, endogenous oligodendrogenesis and remyelination processes are limited by the upregulation of remyelination-inhibitory molecules in the post-injury microenvironment. Multiple growth factors/molecules have been shown to promote OL differentiation and myelination. APPROACH In this study we screened these therapeutics and found that 3, 3', 5-triiodothyronine (T3) is the most effective in promoting oligodendrogenesis and OL maturation in vitro. However, systemic administration of T3 to achieve therapeutic doses in the injured spinal cord is likely to induce hyperthyroidism, resulting in serious side effects. MAIN RESULTS In this study we developed a novel hydrogel-based drug delivery system for local delivery of T3 to the injury site without eliciting systemic toxicity. SIGNIFICANCE Using a clinically relevant cervical contusion injury model, we demonstrate that local delivery of T3 at doses comparable to safe human doses promoted new mature OL formation and myelination after SCI.
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Affiliation(s)
- Robert B Shultz
- School of Biomedical Engineering, Science and Health Systems, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, United States of America
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12
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Squair JW, West CR, Popok D, Assinck P, Liu J, Tetzlaff W, Krassioukov AV. High Thoracic Contusion Model for the Investigation of Cardiovascular Function after Spinal Cord Injury. J Neurotrauma 2017; 34:671-684. [DOI: 10.1089/neu.2016.4518] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Affiliation(s)
- Jordan W. Squair
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
- MD/PhD Training Program, University of British Columbia, Vancouver, British Columbia, Canada
| | - Christopher R. West
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - David Popok
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
| | - Peggy Assinck
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
- Graduate Program in Neuroscience, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jie Liu
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
| | - Wolfram Tetzlaff
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
- Department of Zoology, Faculty of Science, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Andrei V. Krassioukov
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
- Department of Medicine, Division of Physical Medicine and Rehabilitation, University of British Columbia, Vancouver, British Columbia, Canada
- GF Strong Rehabilitation Centre, Vancouver Health Authority, Vancouver, British Columbia, Canada
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13
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Wang Z, Nong J, Shultz RB, Zhang Z, Kim T, Tom VJ, Ponnappan RK, Zhong Y. Local delivery of minocycline from metal ion-assisted self-assembled complexes promotes neuroprotection and functional recovery after spinal cord injury. Biomaterials 2016; 112:62-71. [PMID: 27744221 DOI: 10.1016/j.biomaterials.2016.10.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 10/02/2016] [Indexed: 02/09/2023]
Abstract
Many mechanisms contribute to the secondary injury cascades following traumatic spinal cord injury (SCI). However, most current treatment strategies only target one or a few elements in the injury cascades, and have been largely unsuccessful in clinical trials. Minocycline hydrochloride (MH) is a clinically available antibiotic and anti-inflammatory drug that has been shown to target a broad range of secondary injury mechanisms via its anti-inflammatory, anti-oxidant, and anti-apoptotic properties. However, MH is only neuroprotective at high concentrations. The inability to translate the high doses of MH used in experimental animals to tolerable doses in human patients limits its clinical efficacy. In addition, the duration of MH treatment is limited because long-term systemic administration of high doses of MH has been shown to cause liver toxicity and even death. We have developed a drug delivery system in the form of hydrogel loaded with polysaccharide-MH complexes self-assembled by metal ions for controlled release of MH. This drug delivery system can be injected into the intrathecal space for local delivery of MH with sufficient dose and duration, without causing any additional tissue damage. We show that local delivery of MH at a dose that is lower than the standard human dose (3 mg/kg) was more effective in reducing secondary injury and promoting locomotor functional recovery than systemic injection of MH with the highest dose and duration reported in experimental animal SCI (90-135 mg/kg).
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Affiliation(s)
- Zhicheng Wang
- School of Biomedical Engineering, Science and Health Systems, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA
| | - Jia Nong
- School of Biomedical Engineering, Science and Health Systems, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA
| | - Robert B Shultz
- School of Biomedical Engineering, Science and Health Systems, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA
| | - Zhiling Zhang
- School of Biomedical Engineering, Science and Health Systems, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA
| | - Taegyo Kim
- Spinal Cord Research Center, Department of Neurobiology & Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Veronica J Tom
- Spinal Cord Research Center, Department of Neurobiology & Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Ravi K Ponnappan
- Department of Orthopaedic Surgery, Drexel University College of Medicine, Philadelphia, PA 19102, USA
| | - Yinghui Zhong
- School of Biomedical Engineering, Science and Health Systems, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA.
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Sparrey CJ, Salegio EA, Camisa W, Tam H, Beattie MS, Bresnahan JC. Mechanical Design and Analysis of a Unilateral Cervical Spinal Cord Contusion Injury Model in Non-Human Primates. J Neurotrauma 2016; 33:1136-49. [PMID: 26670940 DOI: 10.1089/neu.2015.3974] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Non-human primate (NHP) models of spinal cord injury better reflect human injury and provide a better foundation to evaluate potential treatments and functional outcomes. We combined finite element (FE) and surrogate models with impact data derived from in vivo experiments to define the impact mechanics needed to generate a moderate severity unilateral cervical contusion injury in NHPs (Macaca mulatta). Three independent variables (impactor displacement, alignment, and pre-load) were examined to determine their effects on tissue level stresses and strains. Mechanical measures of peak force, peak displacement, peak energy, and tissue stiffness were analyzed as potential determinants of injury severity. Data generated from FE simulations predicted a lateral shift of the spinal cord at high levels of compression (>64%) during impact. Submillimeter changes in mediolateral impactor position over the midline increased peak impact forces (>50%). Surrogate cords established a 0.5 N pre-load protocol for positioning the impactor tip onto the dural surface to define a consistent dorsoventral baseline position before impact, which corresponded with cerebrospinal fluid displacement and entrapment of the spinal cord against the vertebral canal. Based on our simulations, impactor alignment and pre-load were strong contributors to the variable mechanical and functional outcomes observed in in vivo experiments. Peak displacement of 4 mm after a 0.5N pre-load aligned 0.5-1.0 mm over the midline should result in a moderate severity injury; however, the observed peak force and calculated peak energy and tissue stiffness are required to properly characterize the severity and variability of in vivo NHP contusion injuries.
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Affiliation(s)
- Carolyn J Sparrey
- 1 Mechatronic Systems Engineering, Simon Fraser University , Surrey, British Columbia, Canada .,2 International Collaboration on Repair Discoveries (ICORD) , Vancouver, British Columbia, Canada
| | - Ernesto A Salegio
- 3 Department of Neurological Surgery, Brain and Spinal Injury Center, University of California at San Francisco , San Francisco, California
| | - William Camisa
- 4 Taylor Collaboration, St Mary's Medical Center , San Francisco, California
| | - Horace Tam
- 1 Mechatronic Systems Engineering, Simon Fraser University , Surrey, British Columbia, Canada
| | - Michael S Beattie
- 3 Department of Neurological Surgery, Brain and Spinal Injury Center, University of California at San Francisco , San Francisco, California
| | - Jacqueline C Bresnahan
- 3 Department of Neurological Surgery, Brain and Spinal Injury Center, University of California at San Francisco , San Francisco, California
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Mechanism of Forelimb Motor Function Restoration after Cervical Spinal Cord Hemisection in Rats: A Comparison of Juveniles and Adults. Behav Neurol 2016; 2016:1035473. [PMID: 27065569 PMCID: PMC4808747 DOI: 10.1155/2016/1035473] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 01/02/2016] [Accepted: 01/12/2016] [Indexed: 11/25/2022] Open
Abstract
The aim of this study was to investigate forelimb motor function after cervical spinal cord injury in juvenile and adult rats. Both rats received a left segmental hemisection of the spinal cord after C3-C4 laminectomy. Behavioral evaluation of motor function was monitored and assessed using the New Rating Scale (NRS) and Forelimb Locomotor Scale (FLS) and by measuring the range of motion (ROM) of both the elbow and wrist. Complete left forelimb motor paralysis was observed in both rats. The NRS showed motor function recovery restored to 50.2 ± 24.7% in juvenile rats and 34.0 ± 19.8% in adult rats. FLS was 60.4 ± 26.8% in juvenile rats and 46.5 ± 26.9% in adult rats. ROM of the elbow and wrist were 88.9 ± 20.6% and 44.4 ± 24.1% in juvenile rats and 70.0 ± 29.2% and 40.0 ± 21.1% in adult rats. Thus, the NRS and ROM of the elbow showed a significant difference between age groups. These results indicate that left hemisection of the cervical spinal cord was not related to right-sided motor functions. Moreover, while motor paralysis of the left forelimb gradually recovered in both groups, the improvement was greater in juvenile rats.
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Detloff MR, Quiros-Molina D, Javia AS, Daggubati L, Nehlsen AD, Naqvi A, Ninan V, Vannix KN, McMullen MK, Amin S, Ganzer PD, Houlé JD. Delayed Exercise Is Ineffective at Reversing Aberrant Nociceptive Afferent Plasticity or Neuropathic Pain After Spinal Cord Injury in Rats. Neurorehabil Neural Repair 2015; 30:685-700. [PMID: 26671215 DOI: 10.1177/1545968315619698] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Neuropathic pain is a debilitating consequence of spinal cord injury (SCI) that correlates with sensory fiber sprouting. Recent data indicate that exercise initiated early after SCI prevents the development of allodynia and modulated nociceptive afferent plasticity. This study determined if delaying exercise intervention until pain is detected would similarly ameliorate established SCI-induced pain. Adult, female Sprague-Dawley rats with a C5 unilateral contusion were separated into SCI allodynic and SCI non-allodynic cohorts at 14 or 28 days postinjury when half of each group began exercising on automated running wheels. Allodynia, assessed by von Frey testing, was not ameliorated by exercise. Furthermore, rats that began exercise with no allodynia developed paw hypersensitivity within 2 weeks. At the initiation of exercise, the SCI Allodynia group displayed marked overlap of peptidergic and non-peptidergic nociceptive afferents in the C7 and L5 dorsal horn, while the SCI No Allodynia group had scant overlap. At the end of 5 weeks of exercise both the SCI Allodynia and SCI No Allodynia groups had extensive overlap of the 2 c-fiber types. Our findings show that exercise therapy initiated at early stages of allodynia is ineffective at attenuating neuropathic pain, but rather that it induces allodynia-aberrant afferent plasticity in previously pain-free rats. These data, combined with our previous results, suggest that there is a critical therapeutic window when exercise therapy may be effective at treating SCI-induced allodynia and that there are postinjury periods when exercise can be deleterious.
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Affiliation(s)
| | | | - Amy S Javia
- Drexel University College of Medicine, Philadelphia, PA, USA
| | | | | | - Ali Naqvi
- Drexel University College of Medicine, Philadelphia, PA, USA
| | - Vinu Ninan
- Drexel University College of Medicine, Philadelphia, PA, USA
| | | | | | - Sheena Amin
- Drexel University College of Medicine, Philadelphia, PA, USA
| | | | - John D Houlé
- Drexel University College of Medicine, Philadelphia, PA, USA
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17
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Sandrow-Feinberg HR, Houlé JD. Exercise after spinal cord injury as an agent for neuroprotection, regeneration and rehabilitation. Brain Res 2015; 1619:12-21. [PMID: 25866284 PMCID: PMC4540698 DOI: 10.1016/j.brainres.2015.03.052] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 03/27/2015] [Accepted: 03/31/2015] [Indexed: 12/17/2022]
Abstract
Spinal cord injury (SCI) is a traumatic event from which there is limited recovery of function, despite the best efforts of many investigators to devise realistic therapeutic treatments. Partly this is due to the multifaceted nature of SCI, where there is considerable disarray and dysfunction secondary to the initial injury. Contributing to this secondary degeneration is neurotoxicity, vascular dysfunction, glial scarring, neuroinflammation, apoptosis and demyelination. It seems logical that addressing the need for neuroprotection, regeneration and rehabilitation will require different treatment strategies that may be applied at varied stages of the post-injury response. Here we focus on a single strategy, exercise/physical training, which appears to have multiple applications and benefits for an acute or chronic SCI. Exercise has been demonstrated to be advantageous at cellular and biochemical levels, as well as being of benefit for the whole animal or human subject. Data from our lab and others will be discussed to further elucidate the many positive aspects of implementing exercise following injury and to suggest that rehabilitation is not the sole target of a training regimen following SCI. This article is part of a Special Issue entitled SI: Spinal cord injury.
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Affiliation(s)
- Harra R Sandrow-Feinberg
- Department of Neurobiology and Anatomy, Spinal Cord Research Center, Drexel University College of Medicine, 2900 Queen Lane, PA 19129, Philadelphia, United States
| | - John D Houlé
- Department of Neurobiology and Anatomy, Spinal Cord Research Center, Drexel University College of Medicine, 2900 Queen Lane, PA 19129, Philadelphia, United States.
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18
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Li K, Javed E, Scura D, Hala TJ, Seetharam S, Falnikar A, Richard JP, Chorath A, Maragakis NJ, Wright MC, Lepore AC. Human iPS cell-derived astrocyte transplants preserve respiratory function after spinal cord injury. Exp Neurol 2015. [PMID: 26216662 DOI: 10.1016/j.expneurol.2015.07.020] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Transplantation-based replacement of lost and/or dysfunctional astrocytes is a promising therapy for spinal cord injury (SCI) that has not been extensively explored, despite the integral roles played by astrocytes in the central nervous system (CNS). Induced pluripotent stem (iPS) cells are a clinically-relevant source of pluripotent cells that both avoid ethical issues of embryonic stem cells and allow for homogeneous derivation of mature cell types in large quantities, potentially in an autologous fashion. Despite their promise, the iPS cell field is in its infancy with respect to evaluating in vivo graft integration and therapeutic efficacy in SCI models. Astrocytes express the major glutamate transporter, GLT1, which is responsible for the vast majority of glutamate uptake in spinal cord. Following SCI, compromised GLT1 expression/function can increase susceptibility to excitotoxicity. We therefore evaluated intraspinal transplantation of human iPS cell-derived astrocytes (hIPSAs) following cervical contusion SCI as a novel strategy for reconstituting GLT1 expression and for protecting diaphragmatic respiratory neural circuitry. Transplant-derived cells showed robust long-term survival post-injection and efficiently differentiated into astrocytes in injured spinal cord of both immunesuppressed mice and rats. However, the majority of transplant-derived astrocytes did not express high levels of GLT1, particularly at early times post-injection. To enhance their ability to modulate extracellular glutamate levels, we engineered hIPSAs with lentivirus to constitutively express GLT1. Overexpression significantly increased GLT1 protein and functional GLT1-mediated glutamate uptake levels in hIPSAs both in vitro and in vivo post-transplantation. Compared to human fibroblast control and unmodified hIPSA transplantation, GLT1-overexpressing hIPSAs reduced (1) lesion size within the injured cervical spinal cord, (2) morphological denervation by respiratory phrenic motor neurons at the diaphragm neuromuscular junction, and (3) functional diaphragm denervation as measured by recording of spontaneous EMGs and evoked compound muscle action potentials. Our findings demonstrate that hiPSA transplantation is a therapeutically-powerful approach for SCI.
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Affiliation(s)
- Ke Li
- Department of Neuroscience, Farber Institute for Neurosciences, Sidney Kimmel Medical College at Thomas Jefferson University, 900 Walnut Street, JHN 469, Philadelphia, PA 19107, United States.
| | - Elham Javed
- Department of Neuroscience, Farber Institute for Neurosciences, Sidney Kimmel Medical College at Thomas Jefferson University, 900 Walnut Street, JHN 469, Philadelphia, PA 19107, United States.
| | - Daniel Scura
- Department of Neuroscience, Farber Institute for Neurosciences, Sidney Kimmel Medical College at Thomas Jefferson University, 900 Walnut Street, JHN 469, Philadelphia, PA 19107, United States.
| | - Tamara J Hala
- Department of Neuroscience, Farber Institute for Neurosciences, Sidney Kimmel Medical College at Thomas Jefferson University, 900 Walnut Street, JHN 469, Philadelphia, PA 19107, United States.
| | - Suneil Seetharam
- Department of Neuroscience, Farber Institute for Neurosciences, Sidney Kimmel Medical College at Thomas Jefferson University, 900 Walnut Street, JHN 469, Philadelphia, PA 19107, United States.
| | - Aditi Falnikar
- Department of Neuroscience, Farber Institute for Neurosciences, Sidney Kimmel Medical College at Thomas Jefferson University, 900 Walnut Street, JHN 469, Philadelphia, PA 19107, United States.
| | - Jean-Philippe Richard
- Department of Neurology, Johns Hopkins University School of Medicine, 855N. Wolfe St., Rangos 250, Baltimore, MD 21205, United States.
| | - Ashley Chorath
- Department of Neuroscience, Farber Institute for Neurosciences, Sidney Kimmel Medical College at Thomas Jefferson University, 900 Walnut Street, JHN 469, Philadelphia, PA 19107, United States.
| | - Nicholas J Maragakis
- Department of Neurology, Johns Hopkins University School of Medicine, 855N. Wolfe St., Rangos 250, Baltimore, MD 21205, United States.
| | - Megan C Wright
- Department of Biology, Arcadia University, 450S. Easton Rd., 220 Boyer Hall, Glenside, PA 19038, United States.
| | - Angelo C Lepore
- Department of Neuroscience, Farber Institute for Neurosciences, Sidney Kimmel Medical College at Thomas Jefferson University, 900 Walnut Street, JHN 469, Philadelphia, PA 19107, United States.
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Gonzalez-Rothi EJ, Rombola AM, Rousseau CA, Mercier LM, Fitzpatrick GM, Reier PJ, Fuller DD, Lane MA. Spinal interneurons and forelimb plasticity after incomplete cervical spinal cord injury in adult rats. J Neurotrauma 2015; 32:893-907. [PMID: 25625912 DOI: 10.1089/neu.2014.3718] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Cervical spinal cord injury (cSCI) disrupts bulbospinal projections to motoneurons controlling the upper limbs, resulting in significant functional impairments. Ongoing clinical and experimental research has revealed several lines of evidence for functional neuroplasticity and recovery of upper extremity function after SCI. The underlying neural substrates, however, have not been thoroughly characterized. The goals of the present study were to map the intraspinal motor circuitry associated with a defined upper extremity muscle, and evaluate chronic changes in the distribution of this circuit following incomplete cSCI. Injured animals received a high cervical (C2) lateral hemisection (Hx), which compromises supraspinal input to ipsilateral spinal motoneurons controlling the upper extremities (forelimb) in the adult rat. A battery of behavioral tests was used to characterize the time course and extent of forelimb motor recovery over a 16 week period post-injury. A retrograde transneuronal tracer - pseudorabies virus - was used to define the motor and pre-motor circuitry controlling the extensor carpi radialis longus (ECRL) muscle in spinal intact and injured animals. In the spinal intact rat, labeling was observed unilaterally within the ECRL motoneuron pool and within spinal interneurons bilaterally distributed within the dorsal horn and intermediate gray matter. No changes in labeling were observed 16 weeks post-injury, despite a moderate degree of recovery of forelimb motor function. These results suggest that recovery of the forelimb function assessed following C2Hx injury does not involve recruitment of new interneurons into the ipsilateral ECRL motor pathway. However, the functional significance of these existing interneurons to motor recovery requires further exploration.
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Affiliation(s)
- Elisa Janine Gonzalez-Rothi
- 1 Department of Physical Therapy, College of Public Health and Health Professions, McKnight Brain Institute, University of Florida , Gainesville, Florida
| | - Angela M Rombola
- 2 Department of Neuroscience, College of Medicine, McKnight Brain Institute, University of Florida , Gainesville, Florida
| | - Celeste A Rousseau
- 2 Department of Neuroscience, College of Medicine, McKnight Brain Institute, University of Florida , Gainesville, Florida
| | - Lynne M Mercier
- 2 Department of Neuroscience, College of Medicine, McKnight Brain Institute, University of Florida , Gainesville, Florida
| | - Garrett M Fitzpatrick
- 1 Department of Physical Therapy, College of Public Health and Health Professions, McKnight Brain Institute, University of Florida , Gainesville, Florida
| | - Paul J Reier
- 2 Department of Neuroscience, College of Medicine, McKnight Brain Institute, University of Florida , Gainesville, Florida
| | - David D Fuller
- 1 Department of Physical Therapy, College of Public Health and Health Professions, McKnight Brain Institute, University of Florida , Gainesville, Florida
| | - Michael A Lane
- 2 Department of Neuroscience, College of Medicine, McKnight Brain Institute, University of Florida , Gainesville, Florida
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20
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Wen J, Sun D, Tan J, Young W. A consistent, quantifiable, and graded rat lumbosacral spinal cord injury model. J Neurotrauma 2015; 32:875-92. [PMID: 25313633 PMCID: PMC4492780 DOI: 10.1089/neu.2013.3321] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The purpose of this study is to develop a rat lumbosacral spinal cord injury (SCI) model that causes consistent motoneuronal loss and behavior deficits. Most SCI models focus on the thoracic or cervical spinal cord. Lumbosacral SCI accounts for about one third of human SCI but no standardized lumbosacral model is available for evaluating therapies. Twenty-six adult female Sprague-Dawley rats were randomized to three groups: sham (n=9), 25 mm (n=8), and 50 mm (n=9). Sham rats had laminectomy only, while 25 mm and 50 mm rats were injured by dropping a 10 g rod from a height of 25 mm or 50 mm, respectively, onto the L4-5 spinal cord at the T13/L1 vertebral junction. We measured footprint length (FL), toe spreading (TS), intermediate toe spreading (ITS), and sciatic function index (SFI) from walking footprints, and static toe spreading (STS), static intermediate toe spreading (SITS), and static sciatic index (SSI) from standing footprints. At six weeks, we assessed neuronal and white matter loss, quantified axons, diameter, and myelin thickness in the peroneal and tibial nerves, and measured cross-sectional areas of tibialis anterior and gastrocnemius muscle fibers. The result shows that peroneal and tibial motoneurons were respectively distributed in 4.71 mm and 5.01 mm columns in the spinal cord. Dropping a 10-g weight from 25 mm or 50 mm caused 1.5 mm or 3.75 mm gaps in peroneal and tibial motoneuronal columns, respectively, and increased spinal cord white matter loss. Fifty millimeter contusions significantly increased FL and reduced TS, ITS, STS, SITS, SFI, and SSI more than 25 mm contusions, and resulted in smaller axon and myelinated axon diameters in tibial and peroneal nerves and greater atrophy of gastrocnemius and anterior tibialis muscles, than 25 mm contusions. This model of lumbosacral SCI produces consistent and graded loss of white matter, motoneuronal loss, peripheral nerve axonal changes, and anterior tibialis and gastrocnemius muscles atrophy in rats.
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Affiliation(s)
- Junxiang Wen
- 1 Department of Cell Biology and Neuroscience, Rutgers, the State University of New Jersey , Piscataway, New Jersey.,2 Department of Orthopaedics, Tongji University School of Medicine , Shanghai, China
| | - Dongming Sun
- 1 Department of Cell Biology and Neuroscience, Rutgers, the State University of New Jersey , Piscataway, New Jersey
| | - Jun Tan
- 2 Department of Orthopaedics, Tongji University School of Medicine , Shanghai, China
| | - Wise Young
- 1 Department of Cell Biology and Neuroscience, Rutgers, the State University of New Jersey , Piscataway, New Jersey
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21
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Transplantation of glial progenitors that overexpress glutamate transporter GLT1 preserves diaphragm function following cervical SCI. Mol Ther 2014; 23:533-48. [PMID: 25492561 DOI: 10.1038/mt.2014.236] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 12/02/2014] [Indexed: 01/14/2023] Open
Abstract
Approximately half of traumatic spinal cord injury (SCI) cases affect cervical regions, resulting in chronic respiratory compromise. The majority of these injuries affect midcervical levels, the location of phrenic motor neurons (PMNs) that innervate the diaphragm. A valuable opportunity exists following SCI for preventing PMN loss that occurs during secondary degeneration. One of the primary causes of secondary injury is excitotoxicity due to dysregulation of extracellular glutamate homeostasis. Astrocytes express glutamate transporter 1 (GLT1), which is responsible for the majority of CNS glutamate clearance. Given our observations of GLT1 dysfunction post-SCI, we evaluated intraspinal transplantation of Glial-Restricted Precursors (GRPs)--a class of lineage-restricted astrocyte progenitors--into ventral horn following cervical hemicontusion as a novel strategy for reconstituting GLT1 function, preventing excitotoxicity and protecting PMNs in the acutely injured spinal cord. We find that unmodified transplants express low levels of GLT1 in the injured spinal cord. To enhance their therapeutic properties, we engineered GRPs with AAV8 to overexpress GLT1 only in astrocytes using the GFA2 promoter, resulting in significantly increased GLT1 protein expression and functional glutamate uptake following astrocyte differentiation in vitro and after transplantation into C4 hemicontusion. Compared to medium-only control and unmodified GRPs, GLT1-overexpressing transplants reduced lesion size, diaphragm denervation and diaphragm dysfunction. Our findings demonstrate transplantation-based replacement of astrocyte GLT1 is a promising approach for SCI.
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22
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Deng LX, Walker C, Xu XM. Schwann cell transplantation and descending propriospinal regeneration after spinal cord injury. Brain Res 2014; 1619:104-14. [PMID: 25257034 DOI: 10.1016/j.brainres.2014.09.038] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 09/08/2014] [Accepted: 09/15/2014] [Indexed: 01/15/2023]
Abstract
After spinal cord injury (SCI), poor ability of damaged axons of the central nervous system (CNS) to regenerate causes very limited functional recovery. Schwann cells (SCs) have been widely explored as promising donors for transplantation to promote axonal regeneration in the CNS including the spinal cord. Compared with other CNS axonal pathways, injured propriospinal tracts display the strongest regenerative response to SC transplantation. Even without providing additional neurotrophic factors, propriospinal axons can grow into the SC environment which is rarely seen in supraspinal tracts. Propriospinal tract has been found to respond to several important neurotrophic factors secreted by SCs. Therefore, the SC is considered to be one of the most promising candidates for cell-based therapies for SCI. Since many reviews have already appeared on topics of SC transplantation in SCI repair, this review will focus particularly on the rationale of SC transplantation in mediating descending propriospinal axonal regeneration as well as optimizing such regeneration by using different combinatorial strategies. This article is part of a Special Issue entitled SI: Spinal cord injury.
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Affiliation(s)
- Ling-Xiao Deng
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Goodman and Campbell Brain and Spine, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
| | - Chandler Walker
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Goodman and Campbell Brain and Spine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Xiao-Ming Xu
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Department of Neurological Surgery, Goodman and Campbell Brain and Spine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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Putatunda R, Hala TJ, Chin J, Lepore AC. Chronic at-level thermal hyperalgesia following rat cervical contusion spinal cord injury is accompanied by neuronal and astrocyte activation and loss of the astrocyte glutamate transporter, GLT1, in superficial dorsal horn. Brain Res 2014; 1581:64-79. [PMID: 24833066 DOI: 10.1016/j.brainres.2014.05.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 04/30/2014] [Accepted: 05/03/2014] [Indexed: 12/23/2022]
Abstract
Neuropathic pain is a form of pathological nociception that occurs in a significant portion of traumatic spinal cord injury (SCI) patients, resulting in debilitating and often long-term physical and psychological burdens. While many peripheral and central mechanisms have been implicated in neuropathic pain, central sensitization of dorsal horn spinothalamic tract (STT) neurons is a major underlying substrate. Furthermore, dysregulation of extracellular glutamate homeostasis and chronic astrocyte activation play important underlying roles in persistent hyperexcitability of these superficial dorsal horn neurons. To date, central sensitization and astrocyte changes have not been characterized in cervical SCI-induced neuropathic pain models, despite the fact that a major portion of SCI patients suffer contusion trauma to cervical spinal cord. In this study, we have characterized 2 rat models of unilateral cervical contusion SCI that behaviorally result in chronic persistence of thermal hyperalgesia in the ipsilateral forepaw. In addition, we find that STT neurons are chronically activated in both models when compared to laminectomy-only uninjured rats. Finally, persistent astrocyte activation and significantly reduced expression of the major CNS glutamate transporter, GLT1, in superficial dorsal horn astrocytes are associated with both excitability changes in STT neurons and the neuropathic pain behavioral phenotype. In conclusion, we have characterized clinically-relevant rodent models of cervical contusion-induced neuropathic pain that result in chronic activation of both STT neurons and astrocytes, as well as compromise in astrocyte glutamate transporter expression. These models can be used as important tools to further study mechanisms underlying neuropathic pain post-SCI and to test potential therapeutic interventions.
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Affiliation(s)
- Rajarshi Putatunda
- Department of Neuroscience, Farber Institute for Neurosciences, Thomas Jefferson University Medical College, 900 Walnut Street, JHN 469, Philadelphia, PA 19107, USA
| | - Tamara J Hala
- Department of Neuroscience, Farber Institute for Neurosciences, Thomas Jefferson University Medical College, 900 Walnut Street, JHN 469, Philadelphia, PA 19107, USA
| | - Jeannie Chin
- Department of Neuroscience, Farber Institute for Neurosciences, Thomas Jefferson University Medical College, 900 Walnut Street, JHN 469, Philadelphia, PA 19107, USA
| | - Angelo C Lepore
- Department of Neuroscience, Farber Institute for Neurosciences, Thomas Jefferson University Medical College, 900 Walnut Street, JHN 469, Philadelphia, PA 19107, USA.
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Detloff MR, Smith EJ, Quiros Molina D, Ganzer PD, Houlé JD. Acute exercise prevents the development of neuropathic pain and the sprouting of non-peptidergic (GDNF- and artemin-responsive) c-fibers after spinal cord injury. Exp Neurol 2014; 255:38-48. [PMID: 24560714 PMCID: PMC4036591 DOI: 10.1016/j.expneurol.2014.02.013] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 01/29/2014] [Accepted: 02/14/2014] [Indexed: 11/18/2022]
Abstract
Spinal cord injury (SCI) impaired sensory fiber transmission leads to chronic, debilitating neuropathic pain. Sensory afferents are responsive to neurotrophic factors, molecules that are known to promote survival and maintenance of neurons, and regulate sensory neuron transduction of peripheral stimuli. A subset of primary afferent fibers responds only to the glial cell-line derived neurotrophic factor (GDNF) family of ligands (GFLs) and is non-peptidergic. In peripheral nerve injury models, restoration of GDNF or artemin (another GFL) to pre-injury levels within the spinal cord attenuates neuropathic pain. One non-invasive approach to increase the levels of GFLs in the spinal cord is through exercise (Ex), and to date exercise training is the only ameliorative, non-pharmacological treatment for SCI-induced neuropathic pain. The purpose of this study was 3-fold: 1) to determine whether exercise affects the onset of SCI-induced neuropathic pain; 2) to examine the temporal profile of GDNF and artemin in the dorsal root ganglia and spinal cord dorsal horn regions associated with forepaw dermatomes after SCI and Ex; and 3) to characterize GFL-responsive sensory fiber plasticity after SCI and Ex. Adult, female, Sprague-Dawley rats received a moderate, unilateral spinal cord contusion at C5. A subset of rats was exercised (SCI+Ex) on automated running wheels for 20min, 5days/week starting at 5days post-injury (dpi), continuing until 9 or 37dpi. Hargreaves' and von Frey testing was performed preoperatively and weekly post-SCI. Forty-two percent of rats in the unexercised group exhibited tactile allodynia of the forepaws while the other 58% retained normal sensation. The development of SCI-induced neuropathic pain correlated with a marked decrease in the levels of GDNF and artemin in the spinal cord and DRGs. Additionally, a dramatic increase in the density and the distribution throughout the dorsal horn of GFL-responsive afferents was observed in rats with SCI-induced allodynia. Importantly, in SCI rats that received Ex, the incidence of tactile allodynia decreased to 7% (1/17) and there was maintenance of GDNF and artemin at normal levels, with a normal distribution of GFL-responsive fibers. These data suggest that GFLs and/or their downstream effectors may be important modulators of pain fiber plasticity, representing effective targets for anti-allodynic therapeutics. Furthermore, we highlight the potent beneficial effects of acute exercise after SCI.
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Affiliation(s)
- Megan Ryan Detloff
- Department of Neurobiology and Anatomy, Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA 19129, USA.
| | - Evan J Smith
- Department of Neurobiology and Anatomy, Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Daniel Quiros Molina
- Department of Neurobiology and Anatomy, Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Patrick D Ganzer
- Department of Neurobiology and Anatomy, Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - John D Houlé
- Department of Neurobiology and Anatomy, Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA 19129, USA
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25
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Detloff MR, Wade RE, Houlé JD. Chronic at- and below-level pain after moderate unilateral cervical spinal cord contusion in rats. J Neurotrauma 2013; 30:884-90. [PMID: 23216008 DOI: 10.1089/neu.2012.2632] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Chronic neuropathic pain is a significant consequence of spinal cord injury (SCI) that is associated with evoked pain, including allodynia and/or hyperalgesia. Allodynia is defined as a painful response to normally innocuous stimuli, and hyperalgesia occurs when there is an amplified pain response to normally noxious stimuli. We describe a model of a unilateral cervical level (C5) contusion injury where sensory recovery was assessed weekly for 6 weeks in 32 adult, female, Sprague-Dawley rats. Bilateral thermal hyperalgesia and tactile allodynia are detectable in the fore- and hindpaws as early as 7 days post-injury (dpi) and persist for at least 42 days. Paw withdrawal latency in response to a noxious thermal stimulus significantly intra-animal pre-operative values. Change in paw withdrawal latency plateaued at 21 dpi. Interestingly, bilateral forepaw allodynia develops in fewer than 40% of rats as measured by von Frey monofilament testing. Similar results occur in the hindpaws, where bilateral allodynia occurs in 46% of rats with SCI. The contralesional forepaw and both hindpaws of rats showed a slight increase in paw withdrawal threshold to tactile stimuli acutely after SCI, corresponding to ipsilesional forelimb motor deficits that resolve over time. That there is no difference among allodynic and non-allodynic groups in overall spared tissue or specifically of the dorsal column or ventrolateral white matter where ascending sensory tracts reside suggests that SCI-induced pain does not depend solely on the size or extent of the lesion, but that other mechanisms are in play. These observations provide a valid model system for future testing of therapeutic interventions to prevent the onset or to reduce the debilitating effects of chronic neuropathic pain after SCI.
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Affiliation(s)
- Megan Ryan Detloff
- Spinal Cord Research Center, Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA.
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26
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Combination of Chondroitinase ABC, Glial Cell Line–Derived Neurotrophic Factor and Nogo A Antibody Delayed-Release Microspheres Promotes the Functional Recovery of Spinal Cord Injury. J Craniofac Surg 2013; 24:2153-7. [DOI: 10.1097/01.scs.0000436700.65891.3b] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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27
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Haas C, Fischer I. Human astrocytes derived from glial restricted progenitors support regeneration of the injured spinal cord. J Neurotrauma 2013; 30:1035-52. [PMID: 23635322 DOI: 10.1089/neu.2013.2915] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Cellular transplantation using neural stem cells and progenitors is a promising therapeutic strategy that has the potential to replace lost cells, modulate the injury environment, and create a permissive environment for the regeneration of injured host axons. Our research has focused on the use of human glial restricted progenitors (hGRP) and derived astrocytes. In the current study, we examined the morphological and phenotypic properties of hGRP prepared from the fetal central nervous system by clinically-approved protocols, compared with astrocytes derived from hGRP prepared by treatment with ciliary neurotrophic factor or bone morphogenetic protein 4. These differentiation protocols generated astrocytes that showed morphological differences and could be classified along an immature to mature spectrum, respectively. Despite these differences, the cells retained morphological and phenotypic plasticity upon a challenge with an alternate differentiation protocol. Importantly, when hGRP and derived astrocytes were transplanted acutely into a cervical dorsal column lesion, they survived and promoted regeneration of long ascending host sensory axons into the graft/lesion site, with no differences among the groups. Further, hGRP taken directly from frozen stocks behaved similarly and also supported regeneration of host axons into the lesion. Our results underscore the dynamic and permissive properties of human fetal astrocytes to promote axonal regeneration. They also suggest that a time-consuming process of pre-differentiation may not be necessary for therapeutic efficacy, and that the banking of large quantities of readily available hGRP can be an appropriate source of permissive cells for transplantation.
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Affiliation(s)
- Christopher Haas
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA
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28
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Houle JD, Côté MP. Axon regeneration and exercise-dependent plasticity after spinal cord injury. Ann N Y Acad Sci 2013; 1279:154-63. [PMID: 23531013 DOI: 10.1111/nyas.12052] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Current dogma states that meaningful recovery of function after spinal cord injury (SCI) will likely require a combination of therapeutic interventions comprised of regenerative/neuroprotective transplants, addition of neurotrophic factors, elimination of inhibitory molecules, functional sensorimotor training, and/or stimulation of paralyzed muscles or spinal circuits. We routinely use (1) peripheral nerve grafts to support and direct axonal regeneration across an incomplete cervical or complete thoracic transection injury, (2) matrix modulation with chondroitinase (ChABC) to facilitate axonal extension beyond the distal graft-spinal cord interface, and (3) exercise, such as forced wheel walking, bicycling, or step training on a treadmill. We and others have demonstrated an increase in spinal cord levels of endogenous neurotrophic factors with exercise, which may be useful in facilitating elongation and/or synaptic activity of regenerating axons and plasticity of spinal neurons below the level of injury.
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Affiliation(s)
- John D Houle
- Department of Neurobiology and Anatomy, Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA 19129, USA.
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29
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Geissler SA, Schmidt CE, Schallert T. Rodent Models and Behavioral Outcomes of Cervical Spinal Cord Injury. ACTA ACUST UNITED AC 2013; Suppl 4. [PMID: 25309824 PMCID: PMC4191831 DOI: 10.4172/2165-7939.s4-001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Rodent spinal cord injury (SCI) models have been developed to examine functional and physiological deficits after spinal cord injury with the hope that these models will elucidate information about human SCI. Models are needed to examine possible treatments and to understand histopathology after SCI; however, they should be considered carefully and chosen based on the goals of the study being performed. Contusion, compression, transection, and other models exist and have the potential to reveal important information about SCI that may be related to human SCI and the outcomes of treatment and timing of intervention.
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Affiliation(s)
- Sydney A Geissler
- Department of Biomedical Engineering, The University of Texas, Austin, TX, USA
| | - Christine E Schmidt
- Department of Biomedical Engineering, The University of Texas, Austin, TX, USA ; Professor, J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
| | - Timothy Schallert
- Professor, Department of Psychology, The University of Texas, Austin, TX, USA ; Professor, Department of Neuroscience, The University of Texas, Austin, TX, USA
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30
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Exogenous BDNF enhances the integration of chronically injured axons that regenerate through a peripheral nerve grafted into a chondroitinase-treated spinal cord injury site. Exp Neurol 2012; 239:91-100. [PMID: 23022460 DOI: 10.1016/j.expneurol.2012.09.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Revised: 08/03/2012] [Accepted: 09/20/2012] [Indexed: 12/20/2022]
Abstract
Although axons lose some of their intrinsic capacity for growth after their developmental period, some axons retain the potential for regrowth after injury. When provided with a growth-promoting substrate such as a peripheral nerve graft (PNG), severed axons regenerate into and through the graft; however, they stop when they reach the glial scar at the distal graft-host interface that is rich with inhibitory chondroitin sulfate proteoglycans. We previously showed that treatment of a spinal cord injury site with chondroitinase (ChABC) allows axons within the graft to traverse the scar and reinnervate spinal cord, where they form functional synapses. While this improvement in outgrowth was significant, it still represented only a small percentage (<20%) of axons compared to the total number of axons that regenerated into the PNG. Here we tested whether providing exogenous brain-derived neurotrophic factor (BDNF) via lentivirus in tissue distal to the PNG would augment regeneration beyond a ChABC-treated glial interface. We found that ChABC treatment alone promoted axonal regeneration but combining ChABC with BDNF-lentivirus did not increase the number of axons that regenerated back into spinal cord. Combining BDNF with ChABC did increase the number of spinal cord neurons that were trans-synaptically activated during electrical stimulation of the graft, as indicated by c-Fos expression, suggesting that BDNF overexpression improved the functional significance of axons that did reinnervate distal spinal cord tissue.
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Abstract
We subjected rats to either partial midcervical or complete upper thoracic spinal cord transections and examined whether combinatorial treatments support motor axonal regeneration into and beyond the lesion. Subjects received cAMP injections into brainstem reticular motor neurons to stimulate their endogenous growth state, bone marrow stromal cell grafts in lesion sites to provide permissive matrices for axonal growth, and brain-derived neurotrophic factor gradients beyond the lesion to stimulate distal growth of motor axons. Findings were compared with several control groups. Combinatorial treatment generated motor axon regeneration beyond both C5 hemisection and T3 complete transection sites. Yet despite formation of synapses with neurons below the lesion, motor outcomes worsened after partial cervical lesions and spasticity worsened after complete transection. These findings highlight the complexity of spinal cord repair and the need for additional control and shaping of axonal regeneration.
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32
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Côté MP, Detloff MR, Wade RE, Lemay MA, Houlé JD. Plasticity in ascending long propriospinal and descending supraspinal pathways in chronic cervical spinal cord injured rats. Front Physiol 2012; 3:330. [PMID: 22934078 PMCID: PMC3429098 DOI: 10.3389/fphys.2012.00330] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 07/28/2012] [Indexed: 11/29/2022] Open
Abstract
The high clinical relevance of models of incomplete cervical spinal cord injury (SCI) creates a need to address the spontaneous neuroplasticity that underlies changes in functional activity that occur over time after SCI. There is accumulating evidence supporting long projecting propriospinal neurons as suitable targets for therapeutic intervention after SCI, but focus has remained primarily oriented toward study of descending pathways. Long ascending axons from propriospinal neurons at lower thoracic and lumbar levels that form inter-enlargement pathways are involved in forelimb-hindlimb coordination during locomotion and are capable of modulating cervical motor output. We used non-invasive magnetic stimulation to assess how a unilateral cervical (C5) spinal contusion might affect transmission in intact, long ascending propriospinal pathways, and influence spinal cord plasticity. Our results show that transmission is facilitated in this pathway on the ipsilesional side as early as 1 week post-SCI. We also probed for descending magnetic motor evoked potentials (MMEPs) and found them absent or greatly reduced on the ipsilesional side as expected. The frequency-dependent depression (FDD) of the H-reflex recorded from the forelimb triceps brachii was bilaterally decreased although Hmax/Mmax was increased only on the ipsilesional side. Behaviorally, stepping recovered, but there were deficits in forelimb–hindlimb coordination as detected by BBB and CatWalk measures. Importantly, epicenter sparing correlated to the amplitude of the MMEPs and locomotor recovery but it was not significantly associated with the inter-enlargement or segmental H-reflex. In summary, our results indicate that complex plasticity occurs after a C5 hemicontusion injury, leading to differential changes in ascending vs. descending pathways, ipsi- vs. contralesional sides even though the lesion was unilateral as well as cervical vs. lumbar local spinal networks.
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Affiliation(s)
- Marie-Pascale Côté
- Department of Neurobiology and Anatomy, Drexel University College of Medicine Philadelphia, PA, USA
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33
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Lee JHT, Streijger F, Tigchelaar S, Maloon M, Liu J, Tetzlaff W, Kwon BK. A contusive model of unilateral cervical spinal cord injury using the infinite horizon impactor. J Vis Exp 2012:3313. [PMID: 22871686 DOI: 10.3791/3313] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
While the majority of human spinal cord injuries occur in the cervical spinal cord, the vast majority of laboratory research employs animal models of spinal cord injury (SCI) in which the thoracic spinal cord is injured. Additionally, because most human cord injuries occur as the result of blunt, non-penetrating trauma (e.g. motor vehicle accident, sporting injury) where the spinal cord is violently struck by displaced bone or soft tissues, the majority of SCI researchers are of the opinion that the most clinically relevant injury models are those in which the spinal cord is rapidly contused.(1) Therefore, an important step in the preclinical evaluation of novel treatments on their way to human translation is an assessment of their efficacy in a model of contusion SCI within the cervical spinal cord. Here, we describe the technical aspects and resultant anatomical and behavioral outcomes of an unilateral contusive model of cervical SCI that employs the Infinite Horizon spinal cord injury impactor. Sprague Dawley rats underwent a left-sided unilateral laminectomy at C5. To optimize the reproducibility of the biomechanical, functional, and histological outcomes of the injury model, we contused the spinal cords using an impact force of 150 kdyn, an impact trajectory of 22.5° (animals rotated at 22.5°), and an impact location off of midline of 1.4 mm. Functional recovery was assessed using the cylinder rearing test, horizontal ladder test, grooming test and modified Montoya's staircase test for up to 6 weeks, after which the spinal cords were evaluated histologically for white and grey matter sparing. The injury model presented here imparts consistent and reproducible biomechanical forces to the spinal cord, an important feature of any experimental SCI model. This results in discrete histological damage to the lateral half of the spinal cord which is largely contained to the ipsilateral side of injury. The injury is well tolerated by the animals, but does result in functional deficits of the forelimb that are significant and sustained in the weeks following injury. The cervical unilateral injury model presented here may be a resource to researchers who wish to evaluate potentially promising therapies prior to human translation.
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Affiliation(s)
- Jae H T Lee
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia
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Comolli N, Donaldson O, Grantier N, Zhukareva V, Tom VJ. Polyvinyl alcohol-polyvinyl pyrrolidone thin films provide local short-term release of anti-inflammatory agents post spinal cord injury. J Biomed Mater Res B Appl Biomater 2012; 100:1867-73. [DOI: 10.1002/jbm.b.32754] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Revised: 03/14/2012] [Accepted: 04/04/2012] [Indexed: 11/08/2022]
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35
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Advances in natural biomaterials for nerve tissue repair. Neurosci Lett 2012; 519:103-14. [DOI: 10.1016/j.neulet.2012.02.027] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Revised: 02/06/2012] [Accepted: 02/08/2012] [Indexed: 12/22/2022]
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Chang IA, Oh MJ, Kim MH, Park SK, Kim BG, Namgung U. Vimentin phosphorylation by Cdc2 in Schwann cell controls axon growth via β1-integrin activation. FASEB J 2012; 26:2401-13. [PMID: 22371530 DOI: 10.1096/fj.11-199018] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Although preconditioning injury on the peripheral nerve induces axonal regenerative capacity in neurons, it is not known whether similar lesion effects occur in glial cells. Here we demonstrate that Schwann cells are activated by peripheral nerve preinjury and primed to mediate axon regeneration. Cdc2, which was induced from Schwann cells after sciatic nerve injury, phosphorylated vimentin almost exclusively in the distal nerve area. Phospho-vimentin-positive Schwann cells showed increased migration activity and were in close contact with process outgrowth of co-cultured neurons. Vimentin phosphorylation by Cdc2 was involved in β1-integrin activation leading to FAK phoshorylation and associated with Erk1/2 activation in Schwann cells. Neurite outgrowth of dorsal root ganglion neurons was increased by co-culture with activated Schwann cells, in which phospho-vimentin signaling was transmitted into β1-integrin activation. Then neurite outgrowth was suppressed by genetic depletion of phospho-vimentin and β1 integrin as well as inhibition of vimentin phosphorylation by Cdc2 inhibitor purvalanol A. The sciatic nerve graft harboring activated Schwann cells into the spinal cord induced Schwann cell migration beyond the graft-host barrier and facilitated regeneration of spinal axons, which was inhibited by purvalanol A pretreatment of the graft. This is the first report to our knowledge demonstrating that activation of phospho-vimentin linked to β1-integrin pathway may mediate transcellular signaling to promote axon growth.
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Affiliation(s)
- In Ae Chang
- Department of Oriental Medicine, Daejeon University, Daejeon 300-716, Republic of Korea
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37
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Khaing ZZ, Geissler SA, Jiang S, Milman BD, Aguilar SV, Schmidt CE, Schallert T. Assessing Forelimb Function after Unilateral Cervical Spinal Cord Injury: Novel Forelimb Tasks Predict Lesion Severity and Recovery. J Neurotrauma 2012; 29:488-98. [DOI: 10.1089/neu.2011.2106] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Zin Z. Khaing
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas
| | - Sydney A. Geissler
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas
| | - Shan Jiang
- Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas
| | - Brian D. Milman
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas
| | - Sandra V. Aguilar
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas
| | - Christine E. Schmidt
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas
| | - Timothy Schallert
- The Department of Psychology, The University of Texas at Austin, Austin, Texas
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Chao OY, Pum ME, Li JS, Huston JP. The grid-walking test: assessment of sensorimotor deficits after moderate or severe dopamine depletion by 6-hydroxydopamine lesions in the dorsal striatum and medial forebrain bundle. Neuroscience 2011; 202:318-25. [PMID: 22142899 DOI: 10.1016/j.neuroscience.2011.11.016] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Revised: 10/31/2011] [Accepted: 11/08/2011] [Indexed: 11/28/2022]
Abstract
The present study aims to evaluate the applicability of the grid-walking test in rats with moderate or severe dopamine-depletion incurred by unilateral nigro-striatal 6-hydroxydopamine (6-OHDA) lesions. Striatum samples were analyzed by high pressure liquid chromatography coupled to electrochemical detection (HPLC-EC) after behavioral testing. In Experiment 1, 2 weeks after the injection of 6-OHDA into the medial forebrain bundle, adult Wistar rats were divided into an l-3,4-dihydroxyphenylalanine (L-dopa) and a vehicle treatment group and their behaviors on the grid were compared. The severely lesioned animals (mean dopamine depletion of 92%) did not exhibit behavioral asymmetry in the number of contralateral foot-slips. However, L-dopa administration selectively reduced the number of foot-slips of the contralateral forelimb when compared with the vehicle group. In Experiment 2, 6-OHDA was injected into the dorsal striatum and foot-slips on the grid were analyzed 4, 9 and 13 days following the lesion. The rats with moderate dopamine-depletion (mean depletion of 54%) exhibited more contralateral forelimb-slips on all testing days. Compared with naive rats, hemiparkinsonian rats also showed more forelimb-slips. These results suggest that the grid-walking test should be a powerful and sensitive behavioral assay for sensory-motor deficits in rat models of nigro-striatal dopamine lesions.
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Affiliation(s)
- O Y Chao
- Center for Behavioral Neuroscience, University of Duesseldorf, Universitaetstr. 1, 40225 Duesseldorf, Germany
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39
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Krisa L, Frederick KL, Canver JC, Stackhouse SK, Shumsky JS, Murray M. Amphetamine-enhanced motor training after cervical contusion injury. J Neurotrauma 2011; 29:971-89. [PMID: 21651384 DOI: 10.1089/neu.2011.1767] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Individually, motor training, pharmacological interventions, and housing animals in an enriched environment (EE) following spinal cord injury (SCI) result in limited functional improvement but, when combined, may enhance motor function. Here, we tested amphetamine (AMPH)-enhanced skilled motor training following a unilateral C3-C4 contusion injury on the qualitative components of reaching and on skilled forelimb function, as assessed using single-pellet and staircase reaching tasks. Kinematic analysis evaluated the quality of the reach, and unskilled locomotor function was also tested. Animals receiving AMPH and skilled forelimb training performed better than operated control animals on qualitative reaching, but not on skilled reaching. Those that received the combination treatment and were housed in EE cages showed significantly less improvement in qualitative reaching and grasping. Kinematic analysis revealed a decrease in digit abduction during skilled reaching among all groups, with no differences among groups. Kinematics provided no evidence that improved function was related to improved quality of reach. There was no evidence of neuroprotection in the cervical spinal cord. The absence of evidence for kinematic improvement or neuroprotection suggested that AMPH-enhanced motor training is due primarily to supraspinal effects, an enhancement of attention during skilled motor training, or plasticity in supraspinal circuitry involved with motor control.
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Affiliation(s)
- Laura Krisa
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129, USA
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Côté MP, Amin AA, Tom VJ, Houle JD. Peripheral nerve grafts support regeneration after spinal cord injury. Neurotherapeutics 2011; 8:294-303. [PMID: 21360238 PMCID: PMC3101823 DOI: 10.1007/s13311-011-0024-6] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Traumatic insults to the spinal cord induce both immediate mechanical damage and subsequent tissue degeneration leading to a substantial physiological, biochemical, and functional reorganization of the spinal cord. Various spinal cord injury (SCI) models have shown the adaptive potential of the spinal cord and its limitations in the case of total or partial absence of supraspinal influence. Meaningful recovery of function after SCI will most likely result from a combination of therapeutic strategies, including neural tissue transplants, exogenous neurotrophic factors, elimination of inhibitory molecules, functional sensorimotor training, and/or electrical stimulation of paralyzed muscles or spinal circuits. Peripheral nerve grafts provide a growth-permissive substratum and local neurotrophic factors to enhance the regenerative effort of axotomized neurons when grafted into the site of injury. Regenerating axons can be directed via the peripheral nerve graft toward an appropriate target, but they fail to extend beyond the distal graft-host interface because of the deposition of growth inhibitors at the site of SCI. One method to facilitate the emergence of axons from a graft into the spinal cord is to digest the chondroitin sulfate proteoglycans that are associated with a glial scar. Importantly, regenerating axons that do exit the graft are capable of forming functional synaptic contacts. These results have been demonstrated in acute injury models in rats and cats and after a chronic injury in rats and have important implications for our continuing efforts to promote structural and functional repair after SCI.
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Affiliation(s)
- Marie-Pascale Côté
- Department of Neurobiology and Anatomy, Spinal Cord Research Center, 2900 Queen Lane, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129 USA
| | - Arthi A. Amin
- Department of Neurobiology and Anatomy, Spinal Cord Research Center, 2900 Queen Lane, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129 USA
| | - Veronica J. Tom
- Department of Neurobiology and Anatomy, Spinal Cord Research Center, 2900 Queen Lane, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129 USA
| | - John D. Houle
- Department of Neurobiology and Anatomy, Spinal Cord Research Center, 2900 Queen Lane, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129 USA
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Tom VJ, Kadakia R, Santi L, Houlé JD. Administration of chondroitinase ABC rostral or caudal to a spinal cord injury site promotes anatomical but not functional plasticity. J Neurotrauma 2010; 26:2323-33. [PMID: 19659409 DOI: 10.1089/neu.2009.1047] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Growth-inhibitory chondroitin sulfate proteoglycans (CSPG) are a primary target for therapeutic strategies after spinal cord injury because of their contribution to the inhibitory nature of glial scar tissue, a major barrier to successful axonal regeneration. Chondroitinase ABC (ChABC) digestion of CSPGs promotes axonal regeneration beyond a lesion site with subsequent functional improvement. ChABC also has been shown to promote sprouting of spared fibers but it is not clear if functional recovery results from such plasticity. Here we sought to better understand the roles rostral or caudal sprouting may play in ChABC-mediated functional improvement. To achieve this, ChABC or vehicle was injected rostral or caudal to a unilateral C5 injury. When injected rostral to a hemisection, ChABC promoted significant sprouting of 5HT+ fibers into dorsal and ventral horns. When ChABC was injected into tissue caudal to a hemisection, no additional sprouting was observed. When injected caudal to a hemicontusion injury, ChABC promoted sprouting of 5HT+ fibers into the ventral horn but not the dorsal horn. None of this sprouting resulted in a change in the synaptic component synapsin, nor did it impact performance in behavioral tests assessing motor function. These data suggest that ChABC-mediated sprouting of spared fibers does not necessarily translate into functional recovery.
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Affiliation(s)
- Veronica J Tom
- Department of Neurobiology and Anatomy, Drexel University College of Medicine , Philadelphia, Pennsylvania, USA
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Sandrow-Feinberg HR, Zhukareva V, Santi L, Miller K, Shumsky JS, Baker DP, Houle JD. PEGylated interferon-beta modulates the acute inflammatory response and recovery when combined with forced exercise following cervical spinal contusion injury. Exp Neurol 2010; 223:439-51. [PMID: 20109445 DOI: 10.1016/j.expneurol.2010.01.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2009] [Revised: 12/31/2009] [Accepted: 01/14/2010] [Indexed: 12/30/2022]
Abstract
Secondary degeneration leads to an expansion of the initial tissue damage sustained during a spinal cord injury (SCI). Dampening the cellular inflammatory response that contributes to this progressive tissue damage is one possible strategy for neuroprotection after acute SCI. We initially examined whether treatment with a PEGylated form of rat interferon-beta (IFN-beta) would modulate the expression of several markers of inflammation and neuroprotection at the site of a unilateral cervical level 5 contusion injury. Adult female Sprague-Dawley rats were injured using the Infinite Horizon Impactor at a force of 200 kdyn (equivalent to a severe injury) and a mean displacement of 1600-1800 mum. A single dose (5x10(6) units) of PEGylated IFN-beta or vehicle was administered 30 min following SCI. Here we demonstrate temporal changes in pro- and anti-inflammatory cytokine levels and the expression of heat shock proteins and iNOS (involved in neuroprotection) at the lesion epicenter and one segment caudally after SCI and PEG IFN-beta treatment. The results suggested a potential therapeutic treatment strategy for modulation of secondary damage after acute SCI. Therefore, we examined whether acute treatment with PEG IFN-beta would improve forelimb function alone or when combined with forced exercise (Ex). Animals began the Ex paradigm 5 days post SCI and continued for 5 days/week over 8 weeks. Locomotion (forelimb locomotor scale [FLS], hindlimb BBB, and TreadScan) and sensorimotor function (grid walking) was tested weekly. Additional outcome measures included lesion size and glial cell reactivity. Significant FLS improvements occurred at 1 week post SCI in the PEGylated IFN-beta-treated group but not at any other time point or with any other treatment approaches. These results suggest that this acute neuroprotective treatment strategy does not translate into long term behavioral recovery even when combined with forced exercise.
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Affiliation(s)
- Harra R Sandrow-Feinberg
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA 19129, USA
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Combining peripheral nerve grafts and chondroitinase promotes functional axonal regeneration in the chronically injured spinal cord. J Neurosci 2010; 29:14881-90. [PMID: 19940184 DOI: 10.1523/jneurosci.3641-09.2009] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Because there currently is no treatment for spinal cord injury, most patients are living with long-standing injuries. Therefore, strategies aimed at promoting restoration of function to the chronically injured spinal cord have high therapeutic value. For successful regeneration, long-injured axons must overcome their poor intrinsic growth potential as well as the inhibitory environment of the glial scar established around the lesion site. Acutely injured axons that regenerate into growth-permissive peripheral nerve grafts (PNGs) reenter host tissue to mediate functional recovery if the distal graft-host interface is treated with chondroitinase ABC (ChABC) to cleave inhibitory chondroitin sulfate proteoglycans in the scar matrix. To determine whether a similar strategy is effective for a chronic injury, we combined grafting of a peripheral nerve into a highly relevant, chronic, cervical contusion site with ChABC treatment of the glial scar and glial cell line-derived neurotrophic factor (GDNF) stimulation of long-injured axons. We tested this combination in two grafting paradigms: (1) a peripheral nerve that was grafted to span a chronic injury site or (2) a PNG that bridged a chronic contusion site with a second, more distal injury site. Unlike GDNF-PBS treatment, GDNF-ChABC treatment facilitated axons to exit the PNG into host tissue and promoted some functional recovery. Electrical stimulation of axons in the peripheral nerve bridge induced c-Fos expression in host neurons, indicative of synaptic contact by regenerating fibers. Thus, our data demonstrate, for the first time, that administering ChABC to a distal graft interface allows for functional axonal regeneration by chronically injured neurons.
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Xu XM, Onifer SM. Transplantation-mediated strategies to promote axonal regeneration following spinal cord injury. Respir Physiol Neurobiol 2009; 169:171-82. [PMID: 19665611 PMCID: PMC2800078 DOI: 10.1016/j.resp.2009.07.016] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 07/16/2009] [Accepted: 07/20/2009] [Indexed: 12/19/2022]
Abstract
Devastating central nervous system injuries and diseases continue to occur in spite of the tremendous efforts of various prevention programs. The enormity and annual escalation of healthcare costs due to them require that therapeutic strategies be responsibly developed. The dysfunctions that occur after injury and disease are primarily due to neurotransmission damage. The last two decades of both experimental and clinical research have demonstrated that neural and non-neural tissue and cell transplantation is a viable option for ameliorating dysfunctions to markedly improve quality of life. Moreover, significant progress has been made with tissue and cell transplantation in studies of pathophysiology, plasticity, sprouting, regeneration, and functional recovery. This article will review information about the ability and potential, particularly for traumatic spinal cord injury, that neural and non-neural tissue and cell transplantation has to replace lost neurons and glia, to reconstruct damaged neural circuitry, and to restore neurotransmitters, hormones, neurotrophic factors, and neurotransmission. Donor tissues and cells to be discussed include peripheral nerve, fetal spinal cord and brain, central and peripheral nervous systems' glia, stem cells, those that have been genetically engineered, and non-neural ones. Combinatorial approaches and clinical research are also reviewed.
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Affiliation(s)
- Xiao-Ming Xu
- Spinal Cord and Brain Injury Research Group, Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, United States.
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Anderson KD, Sharp KG, Hofstadter M, Irvine KA, Murray M, Steward O. Forelimb locomotor assessment scale (FLAS): novel assessment of forelimb dysfunction after cervical spinal cord injury. Exp Neurol 2009; 220:23-33. [PMID: 19733168 DOI: 10.1016/j.expneurol.2009.08.020] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Revised: 08/04/2009] [Accepted: 08/25/2009] [Indexed: 11/30/2022]
Abstract
We describe here a novel forelimb locomotor assessment scale (FLAS) that assesses forelimb use during locomotion in rats injured at the cervical level. A quantitative scale was developed that measures movements of shoulder, elbow, and wrist joints, forepaw position and digit placement, forelimb-hindlimb coordination, compensatory behaviors adopted while walking, and balance. Female Sprague-Dawley rats received graded cervical contusions ranging from 200 to 230 ("mild," n=11) and 250-290 kdyn ("moderate," n=13) between C5 and C8. Rats were videotaped post-injury as they walked along an alley to determine deficits and recovery of forelimb function. Recovery of shoulder and elbow joint movement occurred rapidly (within 1-7 days post-injury), whereas recovery of wrist joint movement was slower and more variable. Most rats in all groups displayed persistent deficits in forepaw and digit movement, but developed compensatory behaviors to allow functional forward locomotion within 1-2 weeks post-injury. Recovery of forelimb function as measured by the FLAS reached a plateau by 3 weeks post-injury in all groups. Rats with mild contusions displayed greater locomotor recovery than rats with moderate contusions, but exhibited persistent deficits compared to sham controls. Reliability was tested by having seven raters (three internal, four external) from different laboratories, independently and blindly score videos of all rats. The multivariate correlation between all raters, all animals, and all time points ranged from r(2)=0.88-0.96 (p<0.0001), indicating a high inter-rater reliability. Thus, the FLAS is a simple, inexpensive, sensitive, and reliable measure of forelimb function during locomotion following cervical SCI.
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Affiliation(s)
- Kim D Anderson
- Reeve-Irvine Research Center, University of California at Irvine School of Medicine, Irvine, 1113 Hewitt Hall, Irvine, CA 92697-1385, USA.
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Sandrow-Feinberg HR, Izzi J, Shumsky JS, Zhukareva V, Houle JD. Forced exercise as a rehabilitation strategy after unilateral cervical spinal cord contusion injury. J Neurotrauma 2009; 26:721-31. [PMID: 19489718 DOI: 10.1089/neu.2008.0750] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Evaluation of locomotor training after spinal cord injury (SCI) has primarily focused on hind limb recovery, with evidence of functional and molecular changes in response to exercise. Since trauma at a cervical (C) level is common in human SCI, we used a unilateral C4 contusion injury model in rats to determine whether forced exercise (Ex) would affect spinal cord biochemistry, anatomy, and recovery of fore and hind limb function. SCI was created with the Infinite Horizon spinal cord impactor device at C4 with a force of 200 Kdyne and a mean displacement of 1600-1800 microm in adult female Sprague-Dawley rats that had been acclimated to a motorized exercise wheel apparatus. Five days post-operatively, the treated group began Ex on the wheel for 20 min per day, 5 days per week for 8 weeks. Wheel speed was increased daily according to the abilities of each animal up to 14 m/min. Control rats were handled daily but were not exposed to Ex. In one set of animals experiencing 5 days of Ex, there was a moderate increase in brain-derived neurotrophic factor (BDNF) and heat shock protein-27 (HSP-27) levels in the lesion epicenter and surrounding tissue. Long-term (8 weeks) survival groups were exposed to weekly behavioral tests to assess qualitative aspects of fore limb and hind limb locomotion (fore limb scale, FLS and BBB [Basso, Beattie, and Bresnahan locomotor rating scale]), as well as sensorimotor (grid) and motor (grip) skills. Biweekly assessment of performance during wheel walking examined gross and fine motor skills. The FLS indicated a significant benefit of Ex during weeks 2-4. The BBB test showed no change with Ex at the end of the 8-week period, however hind limb grid performance was improved during weeks 2-4. Lesion size was not affected by Ex, but the presence of phagocytic and reactive glial cells was reduced with Ex as an intervention. These results suggest that Ex alone can influence the evolution of the injury and transiently improve fore and hind limb function during weeks 2-4 following a cervical SCI.
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Affiliation(s)
- Harra R Sandrow-Feinberg
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129, USA
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Beaumont E, Whitaker CM, Burke DA, Hetman M, Onifer SM. Effects of rolipram on adult rat oligodendrocytes and functional recovery after contusive cervical spinal cord injury. Neuroscience 2009; 163:985-90. [PMID: 19635528 DOI: 10.1016/j.neuroscience.2009.07.039] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2009] [Revised: 07/10/2009] [Accepted: 07/11/2009] [Indexed: 02/04/2023]
Abstract
Traumatic human spinal cord injury (SCI) causes devastating and long-term hardships. These are due to the irreparable primary mechanical injury and secondary injury cascade. In particular, oligodendrocyte cell death, white matter axon damage, spared axon demyelination, and the ensuing dysfunction in action potential conduction lead to the initial deficits and impair functional recovery. For these reasons, and that oligodendrocyte and axon survival may be related, various neuroprotective strategies after spinal cord injury are being investigated. We previously demonstrated that oligodendrocytes in the adult rat epicenter ventrolateral funiculus (VLF) express 3'-5'-cyclic adenosine monophosphate-dependent phosphodiesterase 4 (PDE4) subtypes and that their death was attenuated up to 3 days after contusive cervical SCI when rolipram, a specific inhibitor of PDE4, was administered. Here, we report that (1) there are more oligodendrocyte somata in the adult rat epicenter VLF, (2) descending and ascending axonal conductivity in the VLF improves, and that (3) there are fewer hindlimb footfall errors during grid-walking at 5 weeks after contusive cervical SCI when rolipram is delivered for 2 weeks. This is the first demonstration of improved descending and ascending long-tract axonal conductivity across a SCI with this pharmacological approach. Since descending long-tract axonal conductivity did not return to normal, further evaluations of the pharmacokinetics and therapeutic window of rolipram as well as optimal combinations are necessary before consideration for neuroprotection in humans with SCI.
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Affiliation(s)
- E Beaumont
- Kentucky Spinal Cord Injury Research Center, School of Medicine, University of Louisville, Louisville, KY 40292, USA
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Anderson KD, Sharp KG, Steward O. Bilateral cervical contusion spinal cord injury in rats. Exp Neurol 2009; 220:9-22. [PMID: 19559699 DOI: 10.1016/j.expneurol.2009.06.012] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2008] [Revised: 06/03/2009] [Accepted: 06/17/2009] [Indexed: 11/19/2022]
Abstract
There is increasing motivation to develop clinically relevant experimental models for cervical SCI in rodents and techniques to assess deficits in forelimb function. Here we describe a bilateral cervical contusion model in rats. Female Sprague-Dawley rats received mild or moderate cervical contusion injuries (using the Infinite Horizons device) at C5, C6, or C7/8. Forelimb motor function was assessed using a grip strength meter (GSM); sensory function was assessed by the von Frey hair test; the integrity of the corticospinal tract (CST) was assessed by biotinylated dextran amine (BDA) tract tracing. Mild contusions caused primarily dorsal column (DC) and gray matter (GM) damage while moderate contusions produced additional damage to lateral and ventral tissue. Forelimb and hindlimb function was severely impaired immediately post-injury, but all rats regained the ability to use their hindlimbs for locomotion. Gripping ability was abolished immediately after injury but recovered partially, depending upon the spinal level and severity of the injury. Rats exhibited a loss of sensation in both fore- and hindlimbs that partially recovered, and did not exhibit allodynia. Tract tracing revealed that the main contingent of CST axons in the DC was completely interrupted in all but one animal whereas the dorsolateral CST (dlCST) was partially spared, and dlCST axons gave rise to axons that arborized in the GM caudal to the injury. Our data demonstrate that rats can survive significant bilateral cervical contusion injuries at or below C5 and that forepaw gripping function recovers after mild injuries even when the main component of CST axons in the dorsal column is completely interrupted.
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Affiliation(s)
- Kim D Anderson
- Reeve-Irvine Research Center, University of California, Irvine College of Medicine, Irvine, CA 92697-1385, USA.
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