中国组织工程研究

中国组织工程研究 ›› 2024, Vol. 28 ›› Issue (25): 4054-4059.doi: 10.12307/2024.175

• 干细胞基础实验 basic experiments of stem cells • 上一篇    下一篇

脊髓损伤重塑皮质脊髓运动神经元突触输入的作用

戴家峰1，王丽昭2，韩  齐2，沈洪兴1   

  1. 1上海交通大学医学院附属仁济医院脊柱外科，上海市   200127；2上海交通大学医学院解剖学与生理学系，上海市   200025
  • 收稿日期:2023-05-13 接受日期:2023-06-25 出版日期:2024-09-08 发布日期:2023-11-24
  • 通讯作者: 沈洪兴，博士，主任医师，上海交通大学医学院附属仁济医院脊柱外科，上海市 200127
  • 作者简介:戴家峰，男，1996年生，广东省雷州市人，汉族，上海交通大学医学院在读硕士，主要从事脊髓损伤后轴突再生策略与机制的研究。
  • 基金资助:
    国家自然科学基金资助项目(82072418)，项目负责人：沈洪兴

Role of synaptic input remodeling of corticospinal motor neurons after spinal cord injury

Dai Jiafeng1, Wang Lizhao2, Han Qi2, Shen Hongxing1   

  1. 1Department of Spine Surgery, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China; 2Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
  • Received:2023-05-13 Accepted:2023-06-25 Online:2024-09-08 Published:2023-11-24
  • Contact: Shen Hongxing, MD, Chief physician, Department of Spine Surgery, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
  • About author:Dai Jiafeng, Master candidate, Department of Spine Surgery, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
  • Supported by:
    National Natural Science Foundation of China, No. 82072418 (to SHX)

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摘要：


文题释义：

皮质脊髓运动神经元：是指大脑皮质运动区神经元及其发出的下行纤维，其功能是发放和传递随意运动冲动至下运动神经元，并控制和支配其活动。
突触：两个神经元之间或神经元与效应器细胞之间相互接触并借以传递信息的结构，主要由突触前膜、突触后膜以及突触间隙构成。


背景：脊髓损伤后的功能恢复依赖于运动皮质的功能重塑，然而运动皮质功能重塑的解剖基础研究较少，了解脊髓损伤后运动皮质功能的解剖变化可对脊髓损伤后功能恢复的调控以及康复治疗等提供新的思路以及研究方向。

目的：解析脊髓损伤后初级运动皮质功能重塑的神经回路结构基础。
方法：C57BL/6J小鼠随机分为假手术组、脊髓损伤组。向两组小鼠C4脊髓注射表达Cre重组酶融合蛋白的腺相关病毒，同时在大脑初级运动皮质注射Cre重组酶依赖的分别表达禽类肉瘤/白血病病毒包膜蛋白受体TVA和狂犬病毒糖蛋白的假性狂犬病毒辅助腺相关病毒。第14天时脊髓损伤组小鼠建立C6脊髓背侧半切模型，同时向两组小鼠初级运动皮质注射假性狂犬病毒，7 d后收集小鼠脑部样本，制作冰冻切片，观察支配皮质脊髓运动神经元的输入神经元在脑内的分布情况并进行定量分析。

结果与结论：荧光显微镜观察及定量分析结果发现，两组小鼠支配初级运动皮质脊髓运动神经元的输入神经元在大脑皮质、间脑和中脑均有分布。其中，假手术组小鼠大脑皮质的输入神经元占全脑输入神经元总数的(84.0±3.6)%，间脑占(10.6±2.3)%，中脑占(0.7±0.4)%；脊髓损伤组直接突触的输入神经元在皮质、间脑和中脑中的占比分别为(81.7±1.0)%，(13.1±0.5)%和(1.6±0.8)%。脊髓损伤组初级运动皮质输入神经元在3个区域的比例以及数量均与假手术组无明显差异。脊髓损伤后，各脑区内支配皮质脊髓运动神经元的输入神经元数量无明显变化，提示皮质脊髓束受损后初级运动皮质的功能重塑可能不仅依赖于受损皮质脊髓运动神经元相关突触输入的改变，而更多地与受损神经元自身的转录调控变化有关。

https://orcid.org/0009-0001-5016-3639 (戴家峰)；https://orcid.org/0000-0003-2777-3102 (沈洪兴) 

中国组织工程研究杂志出版内容重点：干细胞；骨髓干细胞；造血干细胞；脂肪干细胞；肿瘤干细胞；胚胎干细胞；脐带脐血干细胞；干细胞诱导；干细胞分化；组织工程

关键词: 脊髓损伤, 皮质脊髓束, 初级运动皮质, 全脑输入, 假性狂犬病毒

Abstract: BACKGROUND: The recovery of function after spinal cord injury depends on the functional remodeling of the motor cortex. However, the anatomical evidence underlying the functional remodeling of the motor cortex is still illusive. Analyzing the anatomical changes in the motor cortex after spinal cord injury can provide new ideas and research directions for regulating functional recovery and rehabilitation after spinal cord injury.
OBJECTIVE: To analyze the neural circuit structural basis of functional remodeling of the primary motor cortex after spinal cord injury.
METHODS: C57BL/6J mice were randomly divided into a sham operation group and a spinal cord injury group. The adeno-associated virus vectors expressing the fusion protein of Cre recombinase were injected into C4 of mice of both groups. The adeno-associated virus vectors with Cre recombinase-inducible expression of avian sarcoma/leukosis envelope glycoprotein receptor TVA and rabies glycoprotein were injected into the primary motor cortex. Fourteen days later, a C6 dorsal hemisection mice model was established in the spinal cord injury group. The pseudotyped rabies virus was injected into the primary motor cortex of mice of both groups. After 7 days, brain samples were collected and frozen sections were made. The distribution of input neurons innervating corticospinal motor neurons in the brain was observed and analyzed quantitatively. 
RESULTS AND CONCLUSION: Fluorescence microscopy observation and quantitative analysis found that input neurons innervating corticospinal motor neurons of the primary motor cortex in mice of both groups were distributed in the cerebral cortex, thalamus and midbrain. Among them, in the sham operation group, the number of input neurons in the mouse cerebral cortex accounted for (84.0±3.6)% of total brain input neurons; that in the thalamus accounted for (10.6±2.3)%, and that in the midbrain accounted for (0.7±0.4)%. Direct synaptic input neurons in the spinal cord injury group accounted for (81.7±1.0)%, (13.1±0.5)%, and (1.6±0.8)% in the cerebral cortex, thalamus and midbrain, respectively. The proportion and number of primary motor cortex input neurons in the three regions of the spinal cord injury group did not differ significantly from that of the sham operation group. After spinal cord injury, the number of input neurons innervating corticospinal pyramidal motor neurons in various brain regions did not change significantly, suggesting that functional remodeling of the motor cortex after spinal cord injury may not only depend on changes in synaptic input related to injured corticospinal motor neurons, but also on transcriptional regulation changes within the injured neurons themselves.

Key words: spinal cord injury, corticospinal tract, primary motor cortex, whole brain inputs, pseudorabies rabies virus

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