腰神经根损伤后神经肌肉接头施旺细胞的作用和表现

Expression and role of Schwann cell in neuromuscular junction following lumbar nerve root injury

目的 研究腰神经根损伤后神经肌肉接头部施旺细胞在神经再支配过程中的作用及与神经元纤维的关系。方法 采用免疫萤光双标记和激光共聚焦扫描技术 ,使用S 10 0多克隆抗体标记施旺细胞 ,抗神经元纤维蛋白 (NF)单克隆抗体标记神经轴突 ,观察了大鼠L5神经根受压后 10、2 0、30和 6 0天比目鱼肌神经肌肉接头的变性及再生修复过程。运用α bungarotoxin(α BTX)萤光结合剂显示运动终板。 结果 肌肉中的神经元纤维蛋白因失神经支配导致大幅度消失 ,随着神经再支配的进行又重新呈现。而位于运动终板及其周围的施旺细胞 ,在失神经支配期间先发出突起并形成一个精细的制作过程覆盖在神经肌内接头。再生期间 ,再生的神经轴突沿施旺细胞搭建的通道生长 ,此过程表现为再生轴突生长始终伴随并落后于施旺细胞的生长。随着神经再支配的逐渐完善 ,这个过程则逐渐消退。

Objective To study the role of Schwann cell in reinnervation and relationship between Schwnn cell and neurofilament after L 5 nerve root compressed in neuromuscular junction. Methods Using immunoflurescence double labelling technique and confocal laser scanning and polyclonal antibody S 100 as Schwann cell marker and monoclonal antibody neurofilament (NF) as axonal marker, we observed the process of degenerating and regenerating neuromuscular junctions in the soleus muscle of the rat 10, 20,30 and 60 d after L 5 nerve root compressed. Motor endplates were visualized with fluorescein conjugated α bungarotoxin(α BTX). Results Denervation resulted in disappearance of NF protein from muscle, reinnervation resulted in the appearance of NF protein. Within days of denervation the Schwann cells began to elaborate fine processes that overlying the neuromuscular junction. Motor axons appeared to be growing along these processes that were made by Schwann cells. These processes were associated with every nerve sprout and longer than the sprout. Reinnervation resulted in a withdrwal of the processes. Conclusion Schwann cells play a primary role in initiating sprouting and in guiding the growth of the resulting sprouts.