大鼠视神经横断伤后视网膜形态学改变及Bcl-2/Bax表达

目的观察大鼠视神经横断伤后,视网膜细胞(RGCs)形态学变化、Bcl-2/Bax蛋白不同时间的表达变化,并探讨其与视神经损伤经过时间的关系。方法采用大鼠球后视神经横断伤动物模型,用Bcl-2和Bax免疫组织化学和HE染色方法观察伤后不同时间RGCs的动态变化。应用图像分析技术,对Bcl-2及Bax免疫反应阳性细胞进行统计学分析。结果视神经横断伤后RGCs数目严重下降,2周内RGCs快速减少,2周以后缓慢减少;伤后Bcl-2、Bax表达随时间不同程度的增加,Bax对损伤反应较Bcl-2稍晚,两者表达均呈现先升后降的趋势,并维持一定的时间。Bcl-2/Bax蛋白表达比率与RGCs存活数目有一定的相关性。结论视神经横断伤后Bcl-2和Bax的表达在伤后不同时间呈现一定的规律性变化,可为损伤时间的推断提供一定依据。

Study of the Morphological Changes and Bcl-2/Bax Expressions in Rat Retina after Optic Nerve Transection

Objective To observe the morphological changes of retina and the alteration of Bcl-2 and Bax expression in rat retina at various intervals after optic nerve transection, and to explore the pathogensis of optic nerve injury and their usefulness in estimation of the post-injury interval. Methods Animal model of posterior intraorbital optic nerve transected rats was used. Retinal samples were collected from these rats killed at various post-injury intervals. Changes of retinal ganglion cells (RGCs) were observed by microscopic examination of the hemtoxylin and eosin (H&E) stained slides. Bcl-2 and Bax expressions in the retina were studied by immunohistochemistry and imaging analysis technique. Results The numbers of RGCs decreased significantly after optic nerve transection(ONT) with an accelerated reduction during the first 2 week after ONT and a slower reduction thereafter. Both Bcl-2 and Bax proteins showed a linear increase in their expressions levels after ONT, with Bcl-2 expression earlier than Bax expression. The levels of both Bcl-2 and Bax expressions maintained for quite a long period of time, and then started to decline. The ratio of Bcl-2/Bax expressions appeared to be related to the numbers of residual RGCs. Conclusion The expressions of both Bcl-2 and Bax proteins in the rat retina alters during various post optic nerve injury intervals, and these changes in Bcl-2 and Bax expressions may be useful in estimation of optic nerve injury interval.