神经生长因子对兔视神经挫伤修复的影响

Effect of NGF on promoting repair of optic nerve contusion in adult rabbits

目的:研究神经生长因子(NGF)对成年兔视神经(ON)挫伤后修复的影响。方法:通过逐级暴露钝性分离钳夹视神经法建立兔视神经挫伤模型,并向玻璃体腔内注入NGF-β1μg(右眼,治疗组),或磷酸盐缓冲液(PBS)0.1m l(左眼,对照组)。挫伤后2周、4周时分别用光镜、电镜和TUNEL技术观察视网膜神经节细胞(RGC s)、视网膜神经纤维层和视神经的改变并作视神经纤维计数。结果:兔视神经挫伤可使RGC s数量减少,表现出细胞坏死、凋亡的特征。视神经病理改变主要是轴突较正常稀疏,部分轴突明显肿胀、空泡变性,轴突与髓鞘间有腔隙形成,髓鞘结构紊乱,出现板层分离。NGF治疗组与对照组相比,前者RGC s、视神经纤维的退变较轻,数量较多,神经纤维有再生现象。同时发现治疗组4周比2周的神经纤维计数明显减少。结论:NGF能够在一定程度上防止轴突的变性坏死,从而阻断因轴突变性而激发RGC s死亡,并促进视神经纤维的再生。

Objective ：To study the effect of nerve growth factor（NGF） on repair of optic nerve contusion in adult rabbits. Methods ： After the adult rabbit optic nerve was contused NGF-β1μg （right eye, treated group）, and 0. 1ml of PBS 1mg/ml（left eye, controlled group） were immediately injected into the vitreous of injured eyes respectively, then retinal ganglion cells（RGCs）, nerve fiberand, optic nerve were examined by microscope, electron microscope and TUNEL method 2 weeks and 4weeks after crush. A computer image analysis was used to count the optic nerve axons. Results：Dying ganglion ceils exhibited morphologic features of apoptosis and necrosis. Optic nerve showed axon swelling, confused structure of myelin sheath, detachment of axolemma. RGCs and optic nerve degeneration in NGF treated group was lighter than that in controlled group, axon regeneration was seen in treated group. The NGF treated group had more optic nerve axons than controlled group . The number of optic nerve axons in NGF treated group in 4th week after injury was less than in 2th week. Conclusion：NGF can prevent axon degeneration to a certain extent, break a cascade of RGCs death by axonal interruption and improve the regeneration of axons.