嗅鞘细胞移植促进脊髓损伤模型大鼠修复损伤区组织的超微结构特征

文题释义：嗅鞘细胞：是一种嗅神经的支持细胞，它起源于嗅基底膜，分布在嗅球，嗅神经和嗅中枢。位于中枢和外周神经系统过渡区，具有降解抑制再生分子、分泌不同神经营养因子、促进神经轴突和髓鞘的再生、改善脊髓损伤后的微环境等重要作用。超微结构：通过透射电子显微镜观察脊髓损伤后损伤部位神经元的细胞膜、细胞器(高尔基复合体，尼氏体，内质网、核糖体、神经微丝、微管)、细胞核(核仁、核周体)；髓鞘，轴突，突触，胶质瘢痕等亚细胞水平的变化。背景：嗅鞘细胞移植治疗脊髓损伤是目前的研究热点，其研究主要探讨脊髓损伤后微环境的影响，嗅鞘细胞移植对脊髓损伤后脊髓超微结构的影响未见报道。目的：观察脊髓损伤后损伤部位神经细胞、轴突、髓鞘、突触和胶质瘢痕的超微结构以及嗅鞘细胞移植对大鼠损伤脊髓的保护和神经修复再生的影响。方法：实验方案经西安交通大学医学部生物医学伦理委员会批准(批准号2018-2048)。将成年健康雌性SD大鼠20只随机分成3组：空白组(4只)仅仅切除T₁₀全部椎板及T₉, T₁₁部分椎板，未对脊髓作其他处理；DF12组(8只)切断脊髓，注射DF12培养液；嗅鞘细胞移植组(8只)切断脊髓，进行嗅鞘细胞移植。于脊髓损伤后1，7，28，56 d，对各组大鼠麻醉后取出脊髓，透射电镜观察脊髓损伤区神经细胞超微结构的变化。结果与结论：①与空白组比较，DF12组大鼠脊髓损伤区神经元胞体内细胞器明显减少，轴突、髓鞘和突触的超微结构发生明显的变化；嗅鞘细胞移植组损伤区的神经元胞体内细胞器明显增加，核仁明显，促进轴突、髓鞘和突触的再生，且胶质瘢痕明显较少；②嗅鞘细胞移植组大鼠星形胶质细胞和毛细血管周细胞的反应比较轻微；③结果说明，脊髓损伤后嗅鞘细胞移植可有效地保护脊髓损伤区的神经组织，促进轴突、髓鞘和突触的再生，抑制神经胶质和周围细胞的增生反应，从而使损伤后微环境有利于神经元、轴突和突触再生。ORCID: 0000-0001-6049-2551(王国毓)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

Olfactory ensheathing cell transplantation promotes the ultrastructure repair at the lesion site of rat models of spinal cord injury

BACKGROUND:Olfactory ensheathing cell transplantation for treating spinal cord injury is an issue of concern,which mainly explores the changes of microenvironment after spinal cord injury.However,the effect of olfactory ensheathing cell transplantation on the ultrastructure of spinal cord after spinal cord injury is never reported.OBJECTIVE:To investigate the ultrastructure alterations of neurocytes,axons,myelin sheaths,synapses,and glial scar after spinal cord injury,and the effect of olfactory ensheathing cell transplantation on the protection and regeneration of nerve repair after spinal cord injury.METHODS:The study was approved by the Ethical Committee of Biomedicine of Medical Department of Xi’an Jiaotong University,approval No.2018-2048.Twenty female Sprague-Dawley rats were divided into three groups:blank control group(n=4,complete laminectomy of T10,partial laminectomy of T9 and T11),DF12 group(n=8,cordotomy+injection of DF12 solution),and olfactory ensheathing cell transplantation group(n=8,cordotomy+olfactory ensheathing cell transplantation).The spinal cord was removed under anesthesia to observe the ultrastructure alterations of neurocytes under transmission electron microscope at 1,7,28 and 56 days after injury.RESULTS AND CONCLUSION:(1) Compared with the blank control group,the organelles in the neurons of the injured lesions were significantly reduced,and the obvious changes were found in the ultrastructure of axon,synapses and myelin sheath in the DF12 group.In the olfactory ensheathing cell transplantation group,the organelles in the neurons of the injured lesions were significantly increased with obvious nucleolus,the regeneration of axon,myelin sheath and synapses were significantly promoted,and the glial scar was significantly decreased.(2) The degree of reaction of the astrocytes and pericytes in the olfactory ensheathing cell transplantation group was light.(3) These findings suggest that olfactory ensheathing cell transplantation can effectively protect the nerve tissues in the lesions after spinal cord injury,promote the regeneration of axon,myelin sheath and synapses,and inhibit the hyperplasia of astrocytes and pericytes,so that the post-injury microenvironment is available for the regeneration of neurons,axons and synapses.