离体初级听觉神经纤维机械损伤后的轴突再生

Neurite regeneration in vitro of the primary auditory nerve in response to mechanical insults

应用神经组织培养技术，作者成功地观察到机械损伤后听神经纤维的轴突再生反应。选用正常１０～１６日龄ＷＬＳ鸡，显微分离听神经节（ＡＧ），离断其双极神经突起后连续培养１２０小时。倒置显微镜下观察神经生长晕并测量其宽度。结果显示，神经胶质和纤维细胞构成培养早期生长晕的主要成分并可见细胞迁移。２４小时可见轴突生长，具有双折光性。７２～９６小时增幅明显，１２０小时生长减缓。作者认为，机械分离致使听神经元双极突起断裂，由此诱发神经修复过程。合成培养基为轴突再生提供外源性促生长因子。ＡＧ组织中非神经元细胞的增殖与迁移对轴突再生，具有诱向和营养双重作用。本文为听神经损伤后的形态修复提供了直接的证据。

Abstract A mechanical injury model for the study of neural repair was created by dissecting the neuraxons of acoustic ganglion(AG)in chick (i,e. bilateral axotomy).Observations were made successfully on neurite growth in the injured AG by means of whole ganglion culture technique. The results demonstrated the outgrowth zone of AG in the earlier stages mainly consist of the non-neuronal cells-gliacytes and fibroblasts. At the 48 hours, newly formed neurites were found and the growth rate reached their maximum value within 72─96 hours. Until the end of culturing periods the survival condition of neurites or non-neuronal cells were well maintained in vitro. Our findings provide a direct evidence for the morphologi-cal repair by injured auditory nerve. It is reasonable to hypothesize based on these observa-tions that dissection of neuronal processes in AG was the trigger factor for the reparation and the nutrient medium supplied the exogenous promoting factors, while the events of prolifera-tion and migration of gliacytes and fibroblasts could have both intrinsic effects of guidance and neurotrophy on the process of the neurite regeneration.