陈旧性神经损伤后雪旺细胞的变化实验研究

目的 观察大鼠坐骨神经损伤后雪旺细胞的变化。方法 切断成年SD大鼠右侧坐骨神经，形成10mm缺损。于术后1～12个月不同时间段取材。标本用p75受体（p75 neurotrophin receptor．p75NTR）、S-100免疫荧光染色，激光共聚焦显微镜观察，另部分标本进行超微结构观察。结果 神经损伤后1个月，损伤远端神经中p75NTR和S-100的表达最多，在损伤后6个月时p75NTR降至正常水平，S-100则在损伤后9个月时消失。电镜下，雪旺细胞出现在神经内膜管内，神经内膜管下及内膜管周围有大量胶原原纤维增生。结论 大鼠坐骨神经损伤后，雪旺细胞中p75NTR的表达增加，但随损伤时间的延长呈进行性下降，伤后6个月时消失。

The changes of Schwann cells in prolonged nerve injuries: an experimental study

Objective The purpose of this experimental study was to investigate the changes of the distal nerve stump at different intervals following sciatic nerve transection. Methods 10 mm of right sciatic nerve defects were created at the mid-thigh level in adult SD rats.1,2,3,4,6 and 12 months following the surgery, the distal nerve stumps were harvested and the expression of p75 neurotrophin receptor (p75NTR) and S-100 protein were observed with immunofluorescent staining under confocal laser scanning microscopy. Transmission electron microscopic observation of the nerve samples was also conducted. Results There was significant upregulation of p75NTR and S-100 protein in the distal nerve stump 1 month following sciatic nerve transection. However, this upregulation of p75NTR did not sustain beyond the 6th month. Similarly, the S-100 protein level was not sustained, and disappeared at the 9th month. At the electron microscopic level, Schwann cells were seen to be located in the endoneurium. Substantial collagenous fibril proliferation at the inner side and around the endoneurium was also observed. Conclusion There was remarkably increased expression of p75NTR in injured nerves. This upregulation, however, disappeared at the 6th month.