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Foster VS, Saez N, King GF, Rank MM. Acute inhibition of acid sensing ion channel 1a after spinal cord injury selectively affects excitatory synaptic transmission, but not intrinsic membrane properties, in deep dorsal horn interneurons. PLoS One 2023; 18:e0289053. [PMID: 37939057 PMCID: PMC10631665 DOI: 10.1371/journal.pone.0289053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 07/10/2023] [Indexed: 11/10/2023] Open
Abstract
Following a spinal cord injury (SCI), secondary damage mechanisms are triggered that cause inflammation and cell death. A key component of this secondary damage is a reduction in local blood flow that initiates a well-characterised ischemic cascade. Downstream hypoxia and acidosis activate acid sensing ion channel 1a (ASIC1a) to trigger cell death. We recently showed that administration of a potent venom-derived inhibitor of ASIC1a, Hi1a, leads to tissue sparing and improved functional recovery when delivered up to 8 h after ischemic stroke. Here, we use whole-cell patch-clamp electrophysiology in a spinal cord slice preparation to assess the effect of acute ASIC1a inhibition, via a single dose of Hi1a, on intrinsic membrane properties and excitatory synaptic transmission long-term after a spinal cord hemisection injury. We focus on a population of interneurons (INs) in the deep dorsal horn (DDH) that play a key role in relaying sensory information to downstream motoneurons. DDH INs in mice treated with Hi1a 1 h after a spinal cord hemisection showed no change in active or passive intrinsic membrane properties measured 4 weeks after SCI. DDH INs, however, exhibit significant changes in the kinetics of spontaneous excitatory postsynaptic currents after a single dose of Hi1a, when compared to naive animals (unlike SCI mice). Our data suggest that acute ASIC1a inhibition exerts selective effects on excitatory synaptic transmission in DDH INs after SCI via specific ligand-gated receptor channels, and has no effect on other voltage-activated channels long-term after SCI.
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Affiliation(s)
- Victoria S. Foster
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland, Australia
- St George’s, University of London, Medical School, London, England
| | - Natalie Saez
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, St Lucia, Queensland, Australia
| | - Glenn F. King
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland, Australia
- Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, St Lucia, Queensland, Australia
| | - Michelle M. Rank
- Department of Anatomy and Physiology, School of Biomedical Science, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, Victoria, Australia
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de Sire A, Moggio L, Marotta N, Curci C, Lippi L, Invernizzi M, Mezian K, Ammendolia A. Impact of rehabilitation on volumetric muscle loss in subjects with traumatic spinal cord injury: A systematic review. NeuroRehabilitation 2023; 52:365-386. [PMID: 36806523 DOI: 10.3233/nre-220277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
BACKGROUND Spinal cord injury (SCI) leads to spinal nerve fiber tract damage resulting in functional impairments. Volumetric muscle loss (VML), a skeletal muscle volume abnormal reduction, is represented by atrophy below the injury level. The strategies for VML management included personalized approaches, and no definite indications are available. OBJECTIVE To identify the rehabilitation effects of VML in subjects with SCI (humans and animals). METHODS PubMed, Scopus, and Web of Science databases were systematically searched to identify longitudinal observational studies with individuals affected by traumatic SCI as participants; rehabilitation treatment as intervention; no control, sham treatment, and electrical stimulation programs as control; total lean body and lower limb lean mass, cross-sectional area, functional gait recovery, muscle thickness, and ultrasound intensity, as outcome. RESULTS Twenty-four longitudinal observational studies were included, evaluating different rehabilitation approaches' effects on the VML reduction in subjects affected by SCI. The data showed that electrical stimulation and treadmill training are effective in reducing the VML in this population. CONCLUSION This systematic review underlines the need to treat subjects with traumatic SCI (humans and animals) with different rehabilitation approaches to prevent VML in the subacute and chronic phases. Further clinical observations are needed to overcome the bias and to define the intervention's timing and modalities.
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Affiliation(s)
- Alessandro de Sire
- Department of Medical and Surgical Sciences, Physical Medicine and Rehabilitation Unit, University of CatanzaroMagna Graecia, Catanzaro, Italy.,Department of Rehabilitation and Sports Medicine, Second Faculty of Medicine, Charles University and University Hospital Motol, Prague, Czech Republic
| | - Lucrezia Moggio
- Department of Medical and Surgical Sciences, Physical Medicine and Rehabilitation Unit, University of CatanzaroMagna Graecia, Catanzaro, Italy.,Rehabilitation Unit, Ospedale degliInfermi, Biella, Italy
| | - Nicola Marotta
- Department of Medical and Surgical Sciences, Physical Medicine and Rehabilitation Unit, University of CatanzaroMagna Graecia, Catanzaro, Italy
| | - Claudio Curci
- Department of Neurosciences, Physical Medicine and Rehabilitation Unit, ASST CarloPoma, Mantova, Italy
| | - Lorenzo Lippi
- Department of Health Sciences, University of Eastern Piedmont "A. Avogadro", Novara, Italy.,Translational Medicine, DipartimentoAttività Integrate Ricerca e Innovazione (DAIRI), AziendaOspedaliera SS. Antonio e Biagio e Cesare Arrigo, Alessandria, Italy
| | - Marco Invernizzi
- Department of Health Sciences, University of Eastern Piedmont "A. Avogadro", Novara, Italy.,Translational Medicine, DipartimentoAttività Integrate Ricerca e Innovazione (DAIRI), AziendaOspedaliera SS. Antonio e Biagio e Cesare Arrigo, Alessandria, Italy
| | - Kamal Mezian
- Department of Rehabilitation Medicine, First Faculty of Medicine, Charles University and General UniversityHospital in Prague, Prague, Czech Republic
| | - Antonio Ammendolia
- Department of Medical and Surgical Sciences, Physical Medicine and Rehabilitation Unit, University of CatanzaroMagna Graecia, Catanzaro, Italy
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Moderate-Intensity Treadmill Exercise Promotes mTOR-Dependent Motor Cortical Neurotrophic Factor Expression and Functional Recovery in a Murine Model of Crush Spinal Cord Injury (SCI). Mol Neurobiol 2023; 60:960-978. [PMID: 36385234 DOI: 10.1007/s12035-022-03117-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 11/01/2022] [Indexed: 11/18/2022]
Abstract
Treadmill exercise is widely considered an effective strategy for restoration of skilled motor function after spinal cord injury (SCI). However, the specific exercise intensity that optimizes recovery and the underlying mechanistic basis of this recovery remain unclear. To that end, we sought to investigate the effect of different treadmill exercise intensities on cortical mTOR activity, a key regulator of functional recovery following CNS trauma, in an animal model of C5 crush spinal cord injury (SCI). Following injury, animals were subjected to treadmill exercise for 4 consecutive weeks at three different intensities (low intensity [LEI]; moderate intensity [MEI]; and high intensity [HEI]). Motor function recovery was assessed by horizontal ladder test, cylinder rearing test, and electrophysiology, while neurotrophic factors and cortical mechanistic target of rapamycin (mTOR) pathway-related proteins were assessed by Western blotting. The activation of the cortical mTOR pathway and axonal sprouting was evaluated by immunofluorescence and the changes of plasticity in motor cortex neurons were assessed by Golgi staining. In keeping with previous studies, we found that 4 weeks of treadmill training resulted in improved skilled motor function, enhanced nerve conduction capability, increased neuroplasticity, and axonal sprouting. Importantly, we also demonstrated that when compared with the LEI group, MEI and HEI groups demonstrated elevated expression of brain-derived neurotrophic factor (BDNF), insulin-like growth factor 1 (IGF-1), phosphorylated ribosomal S6 protein (p-S6), and protein kinase B (p-Akt), consistent with an intensity-dependent activation of the mTOR pathway and neurotrophic factor expression in the motor cortex. We also observed impaired exercise endurance and higher mortality during training in the HEI group than in the LEI and MEI groups. Collectively, our findings suggest that treadmill exercise following SCI is an effective means of promoting recovery and highlight the importance of the cortical mTOR pathway and neurotrophic factors as mediators of this effect. Importantly, our findings also demonstrate that excessive exercise can be detrimental, suggesting that moderation may be the optimal strategy. These findings provide an important foundation for further investigation of treadmill training as a modality for recovery following spinal cord injury and of the underlying mechanisms.
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Xu X, Talifu Z, Zhang CJ, Gao F, Ke H, Pan YZ, Gong H, Du HY, Yu Y, Jing YL, Du LJ, Li JJ, Yang DG. Mechanism of skeletal muscle atrophy after spinal cord injury: A narrative review. Front Nutr 2023; 10:1099143. [PMID: 36937344 PMCID: PMC10020380 DOI: 10.3389/fnut.2023.1099143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 02/20/2023] [Indexed: 03/06/2023] Open
Abstract
Spinal cord injury leads to loss of innervation of skeletal muscle, decreased motor function, and significantly reduced load on skeletal muscle, resulting in atrophy. Factors such as braking, hormone level fluctuation, inflammation, and oxidative stress damage accelerate skeletal muscle atrophy. The atrophy process can result in skeletal muscle cell apoptosis, protein degradation, fat deposition, and other pathophysiological changes. Skeletal muscle atrophy not only hinders the recovery of motor function but is also closely related to many systemic dysfunctions, affecting the prognosis of patients with spinal cord injury. Extensive research on the mechanism of skeletal muscle atrophy and intervention at the molecular level has shown that inflammation and oxidative stress injury are the main mechanisms of skeletal muscle atrophy after spinal cord injury and that multiple pathways are involved. These may become targets of future clinical intervention. However, most of the experimental studies are still at the basic research stage and still have some limitations in clinical application, and most of the clinical treatments are focused on rehabilitation training, so how to develop more efficient interventions in clinical treatment still needs to be further explored. Therefore, this review focuses mainly on the mechanisms of skeletal muscle atrophy after spinal cord injury and summarizes the cytokines and signaling pathways associated with skeletal muscle atrophy in recent studies, hoping to provide new therapeutic ideas for future clinical work.
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Affiliation(s)
- Xin Xu
- School of Rehabilitation, Capital Medical University, Beijing, China
- Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China
- Chinese Institute of Rehabilitation Science, Beijing, China
- Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China
- Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Zuliyaer Talifu
- School of Rehabilitation, Capital Medical University, Beijing, China
- Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China
- Chinese Institute of Rehabilitation Science, Beijing, China
- Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China
- Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
- School of Rehabilitation Sciences and Engineering, University of Health and Rehabilitation Sciences, Qingdao, Shandong, China
| | - Chun-Jia Zhang
- School of Rehabilitation, Capital Medical University, Beijing, China
- Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China
- Chinese Institute of Rehabilitation Science, Beijing, China
- Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China
- Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Feng Gao
- School of Rehabilitation, Capital Medical University, Beijing, China
- Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China
- Chinese Institute of Rehabilitation Science, Beijing, China
- Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China
- Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Han Ke
- School of Rehabilitation, Capital Medical University, Beijing, China
- Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China
- Chinese Institute of Rehabilitation Science, Beijing, China
- Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China
- Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
- School of Rehabilitation Sciences and Engineering, University of Health and Rehabilitation Sciences, Qingdao, Shandong, China
| | - Yun-Zhu Pan
- School of Rehabilitation, Capital Medical University, Beijing, China
- Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China
- Chinese Institute of Rehabilitation Science, Beijing, China
- Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China
- Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
- School of Rehabilitation Sciences and Engineering, University of Health and Rehabilitation Sciences, Qingdao, Shandong, China
| | - Han Gong
- School of Rehabilitation, Capital Medical University, Beijing, China
- Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China
- Chinese Institute of Rehabilitation Science, Beijing, China
- Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China
- Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Hua-Yong Du
- School of Rehabilitation, Capital Medical University, Beijing, China
- Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China
- Chinese Institute of Rehabilitation Science, Beijing, China
- Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China
- Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Yan Yu
- School of Rehabilitation, Capital Medical University, Beijing, China
- Chinese Institute of Rehabilitation Science, Beijing, China
- Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China
- Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Ying-Li Jing
- School of Rehabilitation, Capital Medical University, Beijing, China
- Chinese Institute of Rehabilitation Science, Beijing, China
- Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China
- Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Liang-Jie Du
- School of Rehabilitation, Capital Medical University, Beijing, China
- Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China
- Chinese Institute of Rehabilitation Science, Beijing, China
- Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China
- Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Jian-Jun Li
- School of Rehabilitation, Capital Medical University, Beijing, China
- Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China
- Chinese Institute of Rehabilitation Science, Beijing, China
- Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China
- Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
- School of Rehabilitation Sciences and Engineering, University of Health and Rehabilitation Sciences, Qingdao, Shandong, China
- *Correspondence: Jian-Jun Li
| | - De-Gang Yang
- School of Rehabilitation, Capital Medical University, Beijing, China
- Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China
- Chinese Institute of Rehabilitation Science, Beijing, China
- Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China
- Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
- De-Gang Yang
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Liu JT, Wang SY, Xiao HP, Gu B, Li HN. Effects of methylprednisolone and treadmill training on spinal cord injury in experimental rats. Exp Ther Med 2021; 22:1413. [PMID: 34676006 DOI: 10.3892/etm.2021.10849] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 07/01/2021] [Indexed: 01/26/2023] Open
Abstract
Methylprednisolone (MP) is widely used to treat clinical spinal cord injury (SCI). Treadmill training is also considered an important treatment after SCI to improve motor function in patients, resulting in an evident improvement. Therefore, the present study was designed to evaluate and contrast the effects of MP and treadmill training administered in combination or alone after SCI in adult rats. A rat spinal cord T10 contusion model was induced in Sprague-Dawley rats using an impact device. A total of 40 rats were divided into four groups (n=10 rats/group): the MP, MP + treadmill training, SCI and sham group. At 30 min after injury, MP sodium succinate was injected into the rats of the MP and MP + treadmill training groups. Treadmill training began on the second week post-trauma and was performed for 8 weeks. The results showed that MP therapy combined with treadmill training significantly ameliorated several parameters of hind limb function compared with those by MP treatment alone (all P<0.05). A significantly reduced immunopositive area of Nogo receptor and chondroitin sulfate proteoglycans and reduced relative expression of these mRNAs were found in the MP + treadmill training group (P<0.05) compared with the findings in the MP group. In conclusion, the present study indicated that combined MP and treadmill training treatment improved the recovery of hind limb function in rats with SCI, thus potentially representing a promising strategy to cure SCI.
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Affiliation(s)
- Jian-Tao Liu
- School of Life Sciences, Jiangxi Science and Technology Normal University, Nanchang, Jiangxi 330013, P.R. China
| | - Shuo-Yu Wang
- School of Life Sciences, Jiangxi Science and Technology Normal University, Nanchang, Jiangxi 330013, P.R. China
| | - Han-Ping Xiao
- School of Life Sciences, Jiangxi Science and Technology Normal University, Nanchang, Jiangxi 330013, P.R. China
| | - Bing Gu
- School of Life Sciences, Jiangxi Science and Technology Normal University, Nanchang, Jiangxi 330013, P.R. China
| | - Hua-Nan Li
- Department of Spine Surgery, The Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine, Nanchang, Jiangxi 330006, P.R. China
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6
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Treadmill training based on the overload principle promotes locomotor recovery in a mouse model of chronic spinal cord injury. Exp Neurol 2021; 345:113834. [PMID: 34370998 DOI: 10.1016/j.expneurol.2021.113834] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 07/16/2021] [Accepted: 08/02/2021] [Indexed: 11/21/2022]
Abstract
Rehabilitative treatment, including treadmill training, is considered an important strategy for restoring motor function after spinal cord injury (SCI). However, many unexplained problems persist regarding the appropriate rehabilitative method and the mechanism underlying the beneficial effects of rehabilitation. Moreover, only a few preclinical studies have been performed on rehabilitative interventions for chronic SCI, although most patients have chronic injuries. In fact, several preclinical studies reported that rehabilitative training was less effective when applied during the chronic phase than when applied sooner. While numerous studies have examined the effects of treadmill training during the subacute phase, the training conditions vary considerably among preclinical reports. Therefore, establishing a standard training protocol is essential for achieving beneficial rehabilitation effects at the chronic stage. Since the difficulty of applying an appropriate training load hinders training at constant speeds, it is important to adjust the training intensity in accordance with the exercise tolerance of an individual animal to provide further functional recovery benefits. Here, we created a novel quadrupedal treadmill training protocol based on the overload principle for mice with incomplete thoracic SCI. We subjected SCI model mice to rehabilitative training according to the protocol for two consecutive weeks starting at 42 days after injury. We examined the treadmill speeds at which the mice were able to run based on the severity of paresis and investigated the impact of the protocol on functional recovery. Assessment of running speed changes during the treadmill training period revealed faster treadmill speeds for mice with mild paresis than for those with severe paresis. The training parameters, including the speed and distance traveled, were positively correlated with the changes in motor function. These results suggest that the most suitable running speed during treadmill training differs according to the level of motor dysfunction and that running longer distances has a positive impact on motor functional recovery. Based on this established protocol, we compared functional and histological results between the chronic SCI groups with and without rehabilitation. The gait analyses showed significantly better functional improvement in the rehabilitation group than in the nonrehabilitation group. Histological analyses revealed that the BDNF- and VGLUT1-positive areas of lumbar enlargement were significantly increased in the rehabilitation group. These findings implied that rehabilitation promoted not only motor performance but also motor control, including forelimb-hindlimb coordination, even in chronic SCI, resulting in functional improvement by treadmill training alone. Therefore, rehabilitative training based on the overload principle appears to be one of the appropriate treatment options for incomplete thoracic SCI, and evidence of its efficacy exists in actual clinical settings.
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Liu B, Hu L, Wang L, Xing D, Peng L, Chen P, Zeng F, Liu WV, Liu H, Zha Y. Evaluation of microvascular permeability of skeletal muscle and texture analysis based on DCE-MRI in alloxan-induced diabetic rabbits. Eur Radiol 2021; 31:5669-5679. [PMID: 33547478 DOI: 10.1007/s00330-021-07705-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 11/24/2020] [Accepted: 01/21/2021] [Indexed: 02/08/2023]
Abstract
OBJECTIVES To estimate the microvascular permeability and perfusion of skeletal muscle by using quantitative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and explore the feasibility of using texture analysis (TA) to evaluate subtle structural changes of diabetic muscles. METHODS Twenty-four rabbits were randomly divided into diabetic (n = 14) and control (n = 10) groups, and underwent axial DCE-MRI of the multifidus muscle (0, 4, 8, 12, and 16 weeks after alloxan injection). The pharmacokinetic model was used to calculate the permeability parameters; texture parameters were extracted from volume transfer constant (Ktrans) map. The two-sample t test/Mann-Whitney U test, repeated measures analysis of variance/Friedman test, and Pearson correlations were used for data analysis. RESULTS In the diabetic group, Ktrans and rate constant (Kep) increased significantly at week 8 and then showed a decreasing trend. Extravascular extracellular space volume fraction (Ve) increased and plasma volume fraction (Vp) decreased significantly from the 8th week. Skewness began to decrease at the 4th week. Median Ktrans and entropy increased significantly, while inverse difference moment decreased from the 8th week. Energy decreased while contrast increased only at week 8. Muscle fibre cross-sectional area was negatively correlated with Ve. The capillary-to-fibre ratio was positively correlated with Vp (p < 0.05, all). CONCLUSIONS Quantitative DCE-MRI can be used to evaluate microvascular permeability and perfusion in diabetic skeletal muscle at an early stage; TA based on Ktrans map can identify microarchitectural modifications in diabetic muscles. KEY POINTS • Four quantitative parameters of DCE-MRI can be used to evaluate microvascular permeability and perfusion of skeletal muscle in diabetic models at early stages. • Texture analysis based on Ktrans map can identify subtle structural changes in diabetic muscles.
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Affiliation(s)
- Baiyu Liu
- Department of Radiology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Lei Hu
- Department of Radiology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Li Wang
- Department of Radiology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Dong Xing
- Department of Radiology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Lin Peng
- Department of Radiology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Pianpian Chen
- Department of Radiology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Feifei Zeng
- Department of Radiology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | | | - Huan Liu
- GE Healthcare, Shanghai, 201203, China
| | - Yunfei Zha
- Department of Radiology, Renmin Hospital of Wuhan University, Wuhan, 430060, China.
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Jesus I, Michel-Flutot P, Deramaudt TB, Paucard A, Vanhee V, Vinit S, Bonay M. Effects of aerobic exercise training on muscle plasticity in a mouse model of cervical spinal cord injury. Sci Rep 2021; 11:112. [PMID: 33420246 PMCID: PMC7794462 DOI: 10.1038/s41598-020-80478-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 12/21/2020] [Indexed: 02/06/2023] Open
Abstract
Cervical spinal cord injury (SCI) results in permanent life-altering motor and respiratory deficits. Other than mechanical ventilation for respiratory insufficiency secondary to cervical SCI, effective treatments are lacking and the development of animal models to explore new therapeutic strategies are needed. The aim of this work was to demonstrate the feasibility of using a mouse model of partial cervical spinal hemisection at the second cervical metameric segment (C2) to investigate the impact of 6 weeks training on forced exercise wheel system on locomotor/respiratory plasticity muscles. To measure run capacity locomotor and respiratory functions, incremental exercise tests and diaphragmatic electromyography were done. In addition, muscle fiber type composition and capillary distribution were assessed at 51 days following chronic C2 injury in diaphragm, extensor digitorum communis (EDC), tibialis anterior (TA) and soleus (SOL) muscles. Six-week exercise training increased the running capacity of trained SCI mice. Fiber type composition in EDC, TA and SOL muscles was not modified by our protocol of exercise. The vascularization was increased in all muscle limbs in SCI trained group. No increase in diaphragmatic electromyography amplitude of the diaphragm muscle on the side of SCI was observed, while the contraction duration was significantly decreased in sedentary group compared to trained group. Cross-sectional area of type IIa myofiber in the contralateral diaphragm side of SCI was smaller in trained group. Fiber type distribution between contralateral and ipsilateral diaphragm in SCI sedentary group was affected, while no difference was observed in trained group. In addition, the vascularization of the diaphragm side contralateral to SCI was increased in trained group. All these results suggest an increase in fatigue resistance and a contribution to the running capacity in SCI trained group. Our exercise protocol could be a promising non-invasive strategy to sustain locomotor and respiratory muscle plasticity following SCI.
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Affiliation(s)
- Isley Jesus
- Inserm, END-ICAP, Université Paris-Saclay, UVSQ, 78000, Versailles, France
| | | | | | - Alexia Paucard
- Inserm, END-ICAP, Université Paris-Saclay, UVSQ, 78000, Versailles, France
| | - Valentin Vanhee
- Inserm, END-ICAP, Université Paris-Saclay, UVSQ, 78000, Versailles, France
| | - Stéphane Vinit
- Inserm, END-ICAP, Université Paris-Saclay, UVSQ, 78000, Versailles, France
| | - Marcel Bonay
- Inserm, END-ICAP, Université Paris-Saclay, UVSQ, 78000, Versailles, France.
- Service de Physiologie-Explorations Fonctionnelles; Hôpital Ambroise Paré, Assistance Publique-Hôpitaux de Paris, Boulogne, France.
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9
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Invernizzi M, de Sire A, Renò F, Cisari C, Runza L, Baricich A, Carda S, Fusco N. Spinal Cord Injury as a Model of Bone-Muscle Interactions: Therapeutic Implications From in vitro and in vivo Studies. Front Endocrinol (Lausanne) 2020; 11:204. [PMID: 32351450 PMCID: PMC7174687 DOI: 10.3389/fendo.2020.00204] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Accepted: 03/23/2020] [Indexed: 12/15/2022] Open
Abstract
Spinal cord injuries (SCIs) represent a variety of conditions related to the damage of the spinal cord with consequent musculoskeletal repercussions. The bone and muscle tissues share several catabolic pathways that lead to variable degrees of disability in SCI patients. In this review article, we provide a comprehensive characterization of the available treatment options targeting the skeleton and the bone in the setting of SCI. Among the pharmacological intervention, bisphosphonates, anti-sclerostin monoclonal antibodies, hydrogen sulfide, parathyroid hormone, and RANKL pathway inhibitors represent valuable options for treating bone alterations. Loss phenomena at the level of the muscle can be counteracted with testosterone, anabolic-androgenic steroids, and selective androgen receptor modulators. Exercise and physical therapy are valuable strategies to increase bone and muscle mass. Nutritional interventions could enhance SCI treatment, particularly in the setting of synergistic and multidisciplinary interventions, but there are no specific guidelines available to date. The development of multidisciplinary recommendations is required for a proper clinical management of SCI patients.
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Affiliation(s)
- Marco Invernizzi
- Physical and Rehabilitative Medicine, Department of Health Sciences, University of Eastern Piedmont, Novara, Italy
- *Correspondence: Marco Invernizzi
| | - Alessandro de Sire
- Physical and Rehabilitative Medicine, Department of Health Sciences, University of Eastern Piedmont, Novara, Italy
- Rehabilitation Unit, “Mons. L. Novarese” Hospital, Vercelli, Italy
| | - Filippo Renò
- Innovative Research Laboratory for Wound Healing, Department of Health Sciences, University of Eastern Piedmont, Novara, Italy
| | - Carlo Cisari
- Physical and Rehabilitative Medicine, Department of Health Sciences, University of Eastern Piedmont, Novara, Italy
- Physical Medicine and Rehabilitation Unit, University Hospital “Maggiore della Carità”, Novara, Italy
| | - Letterio Runza
- Division of Pathology, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Alessio Baricich
- Physical and Rehabilitative Medicine, Department of Health Sciences, University of Eastern Piedmont, Novara, Italy
- Physical Medicine and Rehabilitation Unit, University Hospital “Maggiore della Carità”, Novara, Italy
| | - Stefano Carda
- Neuropsychology and Neurorehabilitation Service, Department of Clinical Neuroscience. Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - Nicola Fusco
- Division of Pathology, IEO - European Institute of Oncology IRCCS, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
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10
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Torres-Espín A, Beaudry E, Fenrich K, Fouad K. Rehabilitative Training in Animal Models of Spinal Cord Injury. J Neurotrauma 2019; 35:1970-1985. [PMID: 30074874 DOI: 10.1089/neu.2018.5906] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Rehabilitative motor training is currently one of the most widely used approaches to promote moderate recovery following injuries of the central nervous system. Such training is generally applied in the clinical setting, whereas it is not standard in preclinical research. This is a concern as it is becoming increasingly apparent that neuroplasticity enhancing treatments require training or some form of activity as a co-therapy to promote functional recovery. Despite the importance of training and the many open questions regarding its mechanistic consequences, its use in preclinical animal models is rather limited. Here we review approaches, findings and challenges when training is applied in animal models of spinal cord injury, and we suggest recommendations to facilitate the integration of training using an appropriate study design, into pre-clinical studies.
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Affiliation(s)
- Abel Torres-Espín
- Faculty of Rehabilitation Medicine and Institute for Neuroscience and Mental Health, University of Alberta , Edmonton, Alberta, Canada
| | - Eric Beaudry
- Faculty of Rehabilitation Medicine and Institute for Neuroscience and Mental Health, University of Alberta , Edmonton, Alberta, Canada
| | | | - Karim Fouad
- Faculty of Rehabilitation Medicine and Institute for Neuroscience and Mental Health, University of Alberta , Edmonton, Alberta, Canada
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Massoto TB, Santos ACR, Ramalho BS, Almeida FM, Martinez AMB, Marques SA. Mesenchymal stem cells and treadmill training enhance function and promote tissue preservation after spinal cord injury. Brain Res 2019; 1726:146494. [PMID: 31586628 DOI: 10.1016/j.brainres.2019.146494] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 09/14/2019] [Accepted: 10/02/2019] [Indexed: 01/01/2023]
Abstract
Spinal cord injury (SCI) is considered a serious neurological disorder that can lead to severe sensory, motor and autonomic deficits. In this work, we investigated whether cell therapy associated with physical activity after mouse SCI could promote morphological and functional outcomes, using a lesion model established by our group. Mesenchymal stem cells (8 × 105 cells/2 µL) or DMEM (2 µL), were injected in the epicenter of the lesion at 7 days after SCI, and the mice started a moderate treadmill training 14 days after injury. Functional assessments were performed weekly up to 8 weeks after injury when the morphological analyses were also performed. Four injured groups were analyzed: DMEM (SCI plus DMEM injection), MSCT (SCI plus MSC injection), DMEM + TMT (SCI plus DMEM injection and treadmill training) and MSCT + TMT (SCI plus MSC injection and treadmill training). The animals that received the combined therapy (MSCT + TMT) were able to recover and maintained the better functional results throughout the analyzed period. The morphometric analysis from MSCT + TMT group evidenced a larger spared white matter area and a higher number of preserved myelinated fibers with the majority of them reaching the ideal G-ratio values, when compared to other groups. Ultrastructural analysis from this group, using transmission electron microscopy, showed better tissue preservation with few microcavitations and degenerating nerve fibers. Also, this group exhibited a significantly higher neurotrophin 4 (NT4) expression as compared to the other groups. The results provided by this study support the conclusion that the association of strategies is a potential therapeutic approach to treat SCI, with the possibility of translation into the clinical practice.
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Affiliation(s)
- Tamires Braga Massoto
- Laboratory of Neural Regeneration and Function - Department of Neurobiology, Institute of Biology, Federal Fluminense University, Rio de Janeiro, Brazil
| | - Anne Caroline Rodrigues Santos
- Laboratory of Neural Regeneration and Function - Department of Neurobiology, Institute of Biology, Federal Fluminense University, Rio de Janeiro, Brazil; Laboratory of Neurodegeneration and Repair, Clementino Fraga Filho Hospital, Medical School, Departament of Pathology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; Graduate Program in Pathological Anatomy, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Bruna S Ramalho
- Laboratory of Neurodegeneration and Repair, Clementino Fraga Filho Hospital, Medical School, Departament of Pathology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; Graduate Program in Pathological Anatomy, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Fernanda Martins Almeida
- Graduate Program in Pathological Anatomy, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ana Maria Blanco Martinez
- Laboratory of Neurodegeneration and Repair, Clementino Fraga Filho Hospital, Medical School, Departament of Pathology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; Graduate Program in Pathological Anatomy, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Suelen Adriani Marques
- Laboratory of Neural Regeneration and Function - Department of Neurobiology, Institute of Biology, Federal Fluminense University, Rio de Janeiro, Brazil; Graduate Program in Pathological Anatomy, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
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Effects of treadmill training on microvascular remodeling in the rat after spinal cord injury. Muscle Nerve 2018; 59:370-379. [DOI: 10.1002/mus.26379] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 10/29/2018] [Accepted: 11/03/2018] [Indexed: 01/06/2023]
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Locomotor Training Promotes Time-dependent Functional Recovery after Experimental Spinal Cord Contusion. Neuroscience 2018; 392:258-269. [DOI: 10.1016/j.neuroscience.2018.08.033] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 08/28/2018] [Accepted: 08/29/2018] [Indexed: 12/13/2022]
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Otzel DM, Lee J, Ye F, Borst SE, Yarrow JF. Activity-Based Physical Rehabilitation with Adjuvant Testosterone to Promote Neuromuscular Recovery after Spinal Cord Injury. Int J Mol Sci 2018; 19:ijms19061701. [PMID: 29880749 PMCID: PMC6032131 DOI: 10.3390/ijms19061701] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Revised: 05/31/2018] [Accepted: 06/01/2018] [Indexed: 12/22/2022] Open
Abstract
Neuromuscular impairment and reduced musculoskeletal integrity are hallmarks of spinal cord injury (SCI) that hinder locomotor recovery. These impairments are precipitated by the neurological insult and resulting disuse, which has stimulated interest in activity-based physical rehabilitation therapies (ABTs) that promote neuromuscular plasticity after SCI. However, ABT efficacy declines as SCI severity increases. Additionally, many men with SCI exhibit low testosterone, which may exacerbate neuromusculoskeletal impairment. Incorporating testosterone adjuvant to ABTs may improve musculoskeletal recovery and neuroplasticity because androgens attenuate muscle loss and the slow-to-fast muscle fiber-type transition after SCI, in a manner independent from mechanical strain, and promote motoneuron survival. These neuromusculoskeletal benefits are promising, although testosterone alone produces only limited functional improvement in rodent SCI models. In this review, we discuss the (1) molecular deficits underlying muscle loss after SCI; (2) independent influences of testosterone and locomotor training on neuromuscular function and musculoskeletal integrity post-SCI; (3) hormonal and molecular mechanisms underlying the therapeutic efficacy of these strategies; and (4) evidence supporting a multimodal strategy involving ABT with adjuvant testosterone, as a potential means to promote more comprehensive neuromusculoskeletal recovery than either strategy alone.
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Affiliation(s)
- Dana M Otzel
- Brain Rehabilitation Research Center, Malcom Randall Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL 32608, USA.
| | - Jimmy Lee
- Research Service, Malcom Randall Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL 32608, USA.
| | - Fan Ye
- Research Service, Malcom Randall Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL 32608, USA.
| | - Stephen E Borst
- Department of Applied Physiology, Kinesiology and University of Florida College of Health and Human Performance, Gainesville, FL 32603, USA.
| | - Joshua F Yarrow
- Research Service, Malcom Randall Veterans Affairs Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, FL 32608, USA.
- Division of Endocrinology, Diabetes and Metabolism, University of Florida College of Medicine, Gainesville, FL 32610, USA.
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Raspa A, Bolla E, Cuscona C, Gelain F. Feasible stabilization of chondroitinase abc enables reduced astrogliosis in a chronic model of spinal cord injury. CNS Neurosci Ther 2018; 25:86-100. [PMID: 29855151 DOI: 10.1111/cns.12984] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 05/03/2018] [Accepted: 05/04/2018] [Indexed: 11/30/2022] Open
Abstract
AIMS Usually, spinal cord injury (SCI) develops into a glial scar containing extracellular matrix molecules including chondroitin sulfate proteoglycans (CSPGs). Chondroitinase ABC (ChABC), from Proteus vulgaris degrading the glycosaminoglycan (GAG) side chains of CSPGs, offers the opportunity to improve the final outcome of SCI. However, ChABC usage is limited by its thermal instability, requiring protein structure modifications, consecutive injections at the lesion site, or implantation of infusion pumps. METHODS Aiming at more feasible strategy to preserve ChABC catalytic activity, we assessed various stabilizing agents in different solutions and demonstrated, via a spectrophotometric protocol, that the 2.5 mol/L Sucrose solution best stabilized ChABC as far as 14 days in vitro. RESULTS ChABC activity was improved in both stabilizing and diluted solutions at +37°C, that is, mimicking their usage in vivo. We also verified the safety of the proposed aqueous sucrose solution in terms of viability/cytotoxicity of mouse neural stem cells (NSCs) in both proliferating and differentiating conditions in vitro. Furthermore, we showed that a single intraspinal treatment with ChABC and sucrose reduced reactive gliosis at the injury site in chronic contusive SCI in rats and slightly enhanced their locomotor recovery. CONCLUSION Usage of aqueous sucrose solutions may be a feasible strategy, in combination with rehabilitation, to ameliorate ChABC-based treatments to promote the regeneration of central nervous system injuries.
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Affiliation(s)
- Andrea Raspa
- Opera di San Pio da Pietrelcina, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo (FG), Italy
| | - Edoardo Bolla
- Center for Nanomedicine and Tissue Engineering (CNTE), A.O. Ospedale Niguarda Cà Granda, Piazza dell'Ospedale Maggiore, Milan, Italy
| | - Claudia Cuscona
- Center for Nanomedicine and Tissue Engineering (CNTE), A.O. Ospedale Niguarda Cà Granda, Piazza dell'Ospedale Maggiore, Milan, Italy
| | - Fabrizio Gelain
- Opera di San Pio da Pietrelcina, IRCCS Casa Sollievo della Sofferenza, San Giovanni Rotondo (FG), Italy.,Center for Nanomedicine and Tissue Engineering (CNTE), A.O. Ospedale Niguarda Cà Granda, Piazza dell'Ospedale Maggiore, Milan, Italy
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Zhao BL, Li WT, Zhou XH, Wu SQ, Cao HS, Bao ZR, An LB. Effective robotic assistive pattern of treadmill training for spinal cord injury in a rat model. Exp Ther Med 2018; 15:3283-3294. [PMID: 29545846 PMCID: PMC5840943 DOI: 10.3892/etm.2018.5822] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 01/24/2018] [Indexed: 01/18/2023] Open
Abstract
The purpose of the present study was to establish an effective robotic assistive stepping pattern of body-weight-supported treadmill training based on a rat spinal cord injury (SCI) model and assess the effect by comparing this with another frequently used assistive stepping pattern. The recorded stepping patterns of both hind limbs of trained intact rats were edited to establish a 30-sec playback normal rat stepping pattern (NRSP). Step features (step length, step height, step number and swing duration), BBB scores, latencies, and amplitudes of the transcranial electrical motor-evoked potentials (tceMEPs) and neurofilament 200 (NF200) expression in the spinal cord lesion area during and after 3 weeks of body-weight-supported treadmill training (BWSTT) were compared in rats with spinal contusion receiving NRSP assistance (NRSPA) and those that received manual assistance (MA). Hind limb stepping performance among rats receiving NRSPA during BWSTT was greater than that among rats receiving MA in terms of longer step length, taller step height, and longer swing duration. Furthermore a higher BBB score was also indicated. The rats in the NRSPA group achieved superior results in the tceMEPs assessment and greater NF200 expression in the spinal cord lesion area compared with the rats in the MA group. These findings suggest NRSPA was an effective assistive pattern of treadmill training compared with MA based on the rat SCI model and this approach could be used as a new platform for animal experiments for better understanding the mechanisms of SCI rehabilitation.
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Affiliation(s)
- Bo-Lun Zhao
- Department of Clinical Nursing, School of Nursing, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Wen-Tao Li
- Department of Clinical Nursing, School of Nursing, Dalian University, Dalian, Liaoning 116622, P.R. China
| | - Xiao-Hua Zhou
- Department of Clinical Nursing, School of Nursing, Dalian University, Dalian, Liaoning 116622, P.R. China
| | - Su-Qian Wu
- Department of Clinical Nursing, School of Nursing, Dalian University, Dalian, Liaoning 116622, P.R. China
| | - Hong-Shi Cao
- Department of Clinical Nursing, School of Nursing, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Zhu-Ren Bao
- Department of Clinical Nursing, School of Nursing, Dalian University, Dalian, Liaoning 116622, P.R. China
| | - Li-Bin An
- Department of Clinical Nursing, School of Nursing, Jilin University, Changchun, Jilin 130021, P.R. China
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Is more always better? How different 'doses' of exercise after incomplete spinal cord injury affects the membrane properties of deep dorsal horn interneurons. Exp Neurol 2017; 300:201-211. [PMID: 29146456 DOI: 10.1016/j.expneurol.2017.11.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 10/22/2017] [Accepted: 11/12/2017] [Indexed: 01/12/2023]
Abstract
Interneurons in the deep dorsal horn (DDH) of the spinal cord process somatosensory input, and form an important link between upper and lower motoneurons to subsequently shape motor output. Exercise training after SCI is known to improve functional motor recovery, but little is known about the mechanisms within spinal cord neurons that underlie these improvements. Here we investigate how the properties of DDH interneurons are affected by spinal cord injury (SCI) alone, and SCI in combination with different 'doses' of treadmill exercise training (3, 6, and 9wks). In an adult mouse hemisection model of SCI we used whole-cell patch-clamp electrophysiology to record intrinsic, AP firing and gain modulation properties from DDH interneurons in a horizontal spinal cord slice preparation. We find that neurons within two segments of the injury, both ipsi- and contralateral to the hemisection, are similarly affected by SCI and SCI plus exercise. The passive intrinsic membrane properties input resistance (Rin) and rheobase are sensitive to the effects of recovery time and exercise training after SCI thus altering DDH interneuron excitability. Conversely, select active membrane properties are largely unaffected by either SCI or exercise training. SCI itself causes a mismatch in the expression of voltage-gated subthreshold currents and AP discharge firing type. Over time after SCI, and especially with exercise training (9wks), this mismatched expression is exacerbated. Lastly, amplification properties (i.e. gain of frequency-current relationship) of DDH interneurons are altered by SCI alone and recover spontaneously with no clear effect of exercise training. These results suggest a larger 'dose' of exercise training (9wks) has a strong and selective effect on specific membrane properties, and on the output of interneurons in the vicinity of a SCI. These electrophysiological data provide new insights into the plasticity of DDH interneurons and the mechanisms by which exercise therapy after SCI can improve recovery.
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Tail Nerve Electrical Stimulation and Electro-Acupuncture Can Protect Spinal Motor Neurons and Alleviate Muscle Atrophy after Spinal Cord Transection in Rats. Neural Plast 2017; 2017:7351238. [PMID: 28744378 PMCID: PMC5506460 DOI: 10.1155/2017/7351238] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Revised: 03/08/2017] [Accepted: 03/19/2017] [Indexed: 01/12/2023] Open
Abstract
Spinal cord injury (SCI) often results in death of spinal neurons and atrophy of muscles which they govern. Thus, following SCI, reorganizing the lumbar spinal sensorimotor pathways is crucial to alleviate muscle atrophy. Tail nerve electrical stimulation (TANES) has been shown to activate the central pattern generator (CPG) and improve the locomotion recovery of spinal contused rats. Electroacupuncture (EA) is a traditional Chinese medical practice which has been proven to have a neural protective effect. Here, we examined the effects of TANES and EA on lumbar motor neurons and hindlimb muscle in spinal transected rats, respectively. From the third day postsurgery, rats in the TANES group were treated 5 times a week and those in the EA group were treated once every other day. Four weeks later, both TANES and EA showed a significant impact in promoting survival of lumbar motor neurons and expression of choline acetyltransferase (ChAT) and ameliorating atrophy of hindlimb muscle after SCI. Meanwhile, the expression of neurotrophin-3 (NT-3) in the same spinal cord segment was significantly increased. These findings suggest that TANES and EA can augment the expression of NT-3 in the lumbar spinal cord that appears to protect the motor neurons as well as alleviate muscle atrophy.
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