三叉神经慢性缩窄环术后大鼠行为反应与组织学变化的关系

目的:观察慢性缩窄环术前后大鼠对机械刺激的反应阈值与三叉神经的组织学改变,探讨三叉神经痛的发病机制,为治疗等提供实验基础。方法:在大鼠一侧三叉神经分支眶下神经(ION)行缩窄环术(CCI),观察术后不同时段大鼠对机械刺激的反应阈值及三叉神经组织学改变。结果:1.术后2周到8周,在ION支配区域内,大鼠出现痛觉超敏现象,与术前及对照组比较存在显著差异(P<0.01),术后4周开始逐渐恢复,术后12周左右恢复至术前水平。2.术后2周,I0N-CCI区域神经纤维肿胀,髓鞘脱失,正常结构消失;术后4到8周,神经纤维仍有脱髓鞘改变;术后12周神经纤维密度均匀,髓鞘与轴突比例恢复正常。结论:慢性缩窄环术后大鼠对机械刺激的反应阈值与其局部神经纤维脱髓鞘改变密切相关。

THE RELATION BETWEEN PAIN-RELATED BEHAVIOURS FOLLOWING CHRONIC CONSTRICTION INJURY AND HISTOLOGICAL CHANGES OF TRIGEMINAL NERVE IN THE RAT

Objective: To observe the pain-related behaviours and histological changes before and after chronic constriction injury of the rat trigeminal nerve,explore the machanism of trigeminal neuralgia and provide the basic research for therapy.Methods: An unilateral chronic constriction injury(CCI) was produced by placing loose chromic gut ligatures around the infraorbital nerve(ION).The Pain-related behaviours and the histological changes of ION were observed at different times before and after operation respectively.Result: 1.An allodynia to mechanical stimulation on the territory of ligated ION was found from the 2nd to the 8th week after operation.There was significant difference(P<0.01) in pain threshold,compared with the pre-operation.The thresholds started to increase gradually from the 4th week and reached the original level on 12th week after operation.2.On the 2nd,the 4th and the 8th week after operation,the fibers of the ION were obviously injured.On the 12th week after operation,the injured nerve almost recovered to normal.Conclusion:The abnormal pain-related behaviours of rats following chronic constriction injury appeared to be closely linked to the histological changes in the ION.