Change of motor neurons and skeletal muscles distal to the lesion after spinal cord injury in rats

doi:10.3969/j.issn.2095-4344.2014.33.013

Abstract

Abstract:

BACKGROUND: The majority of studies focus on the lesions of spinal cord injury, while little evidence is available on the change of morphology and structure of distal nerve, muscle and motor endplates following spinal cord injury.
OBJECTIVE: To investigate the time window change of the morphology of motor neurons and skeletal muscles caudal to the lesion after spinal cord injury in rats.
METHODS: Fifty healthy adult Sprague-Dawley rats were randomly divided into three groups: control group (n=5; without treatment), sham operation group (n=10), and spinal cord injury group (n=35). The sham operated rats only received laminectomy. In the spinal cord injury group, rats were subject to complete T₁₀spinal cord injury by total laminectomy and cord transverse resection. Then the morphological change including sciatic nerve, motor endplate and median gastrocnemius was observed for each group at 1, 2, 4, 12, 24 weeks after injury.
RESULTS AND CONCLUSION: (1) The myelin sheath layers of sciatic nerve were separated partially at 4 weeks in rats with spinal cord injury, the myelin sheaths were fragmented with the regeneration of thin-myelinated and unmyelinated axons at 12 weeks. There was a decrease in myelinated axons and an increase in thin-myelinated
and unmyelinated axons at 24 weeks. (2) The synaptic gutters of motor endplate, the presynaptic and postsynaptic membrane and synaptic space were distinct at 4 weeks in rats with spinal cord injury, the degenerated motor endplates coexsisted with the intact ones at 12 weeks. The motor endplate disappeared at 24 weeks. (3) There was a slight decrease in muscle cross-sectional area at 2 weeks in rats with spinal cord injury, but no structural change was found, the membrane of myocytes was partially weakened at 4 weeks, the border of myocytes was obscure with hyperplasia of connective tissue at 12 weeks, and myocytes gathered and in fusion at 24 weeks. As natural history of completely transected spinal cord injury in rats, there were significant changes in morphology of peripheral nerve, motor endplate and skeletal muscles caudal to the lesion at 12 weeks, and the changes were destructive at 24 weeks.

中国组织工程研究杂志出版内容重点：组织构建；骨细胞；软骨细胞；细胞培养；成纤维细胞；血管内皮细胞；骨质疏松；组织工程

全文链接：

Key words: spinal cord injury, neurons, skeletal muscles, morphology

CLC Number:

R318

Wang Yuan-yuan, Hong Yi, Wang Xue-fei, Cai Qing, Tang He-hu, Li Xiang, Liang Guang-xu, Zhang Jun-wei . Change of motor neurons and skeletal muscles distal to the lesion after spinal cord injury in rats[J]. Chinese Journal of Tissue Engineering Research, 2014, 18(33): 5323-5328.

Figures/Tables 3

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