摘要
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。
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.
作者
戴家峰
王丽昭
韩齐
沈洪兴
Dai Jiafeng;Wang Lizhao;Han Qi;Shen Hongxing(Department of Spine Surgery,Renji Hospital,Shanghai Jiao Tong University School of Medicine,Shanghai 200127,China;Department of Anatomy and Physiology,Shanghai Jiao Tong University School of Medicine,Shanghai 200025,China)
出处
《中国组织工程研究》
CAS
北大核心
2024年第25期4054-4059,共6页
Chinese Journal of Tissue Engineering Research
基金
国家自然科学基金资助项目(82072418),项目负责人:沈洪兴。
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
spinal cord injury
corticospinal tract
primary motor cortex
whole brain inputs
pseudorabies rabies virus
作者简介
第一作者: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。https://orcid.org/0009-0001-5016-3639;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,https://orcid.org/0000-0003-2777-3102。
