视神经牵拉伤的实验研究

Experimental studies on stretch injury of optic nerve

目的 研究视神经牵拉伤后不同时期神经组织超微结构的变化及相应的电生理表现。方法 豚鼠单眼视神经牵拉延长 2 0 %～ 2 5 % ,分期行视觉诱发电位检查及取视神经标本进行透视电镜观察。结果 牵拉伤 2 4h内电生理变化明显 ,同期出现轴突水肿、线粒体肿胀、髓鞘松散等变化 ;96h后电生理变化达到高峰 ;9d后有缓慢恢复的趋势 ,同期轴突有萎缩与修复的表现 ;2个月电生理有轻度恢复 ,但部分轴突萎缩现象明显 ,甚至消失 ,胶原纤维增生明显。结论 视神经牵拉损伤后神经纤维超微结构变化明显 ,并伴有相应的电生理表现。

Objective To investigate the ultrastructural and the corresponding electrophysiological changes after stretch injury of the optic nerve at different stages. Methods Single eye optic nerve of each guinea pig was stretched 20%~25% longer than its normal length, flash stimulated visual evoked potentials (flash-VEP) and ultrastructural examination under transmission electron microscopy at different stages were performed.Results There were obvious electrophysiological changes within 24 hours after its injury, accompanied by edema of axons, swelling of mitochondria and loosening of myelin sheath. The electrophysiological changes reached the climax 96 hours after the injury. Nine days later, there was a trend of recovery in electrophysiological changes accompanied by atrophy and repair of axons. Two months later, there were slight recovery of electrophysiological index and significant atrophy, even disappearance of some axons, with proliferation of collagen fibers.Conclusion There are significant ultrastructural changes in optic nerve fibers after stretch injury accompanied by corresponding electrophysiological changes.