地塞米松对光损伤大鼠视细胞凋亡的防治作用

A study on the effect of dexamethasone on optic cell apoptosis in rats with photic injury

目的 :研究地塞米松对光损伤及视细胞凋亡的防治作用 ,以探讨光损伤视细胞凋亡的发生机制。方法 :所有SD大鼠经循环光环境适应 7d ,实验前暗适应 36h。实验A组的大鼠只光照 ,实验B组的大鼠光照 6h后在暗箱中喂养 ,实验a组的大鼠在暗适应后腹腔注射地塞米松再光照 ,实验b组的大鼠光照 6h后在暗箱中喂养 ,且每天应用地塞米松。对经以上处理过的大鼠行灌流固定 ,摘除眼球。光镜标本在常规脱水、透明、石蜡包埋切片后 ,行HE、TUNEL法染色 ,光镜观察。应用CIAS 10 0 0图像分析系统定量检测外核层面积和视细胞凋亡指数 ,所得数据做统计学分析。结果 :在实验A组中 ,随着光照时间的增加 ,视网膜光损伤逐渐加重 ,视细胞凋亡逐渐增多 ,外核层面积逐渐减少。而在实验a组中 ,也出现如实验A组的规律性变化 ,但应用地塞米松后 ,视网膜光损伤程度减轻 ,发生视细胞凋亡的时间延迟 3h。两实验组定量检测结果经统计学分析表明 ,地塞米松对视网膜光损伤及视细胞凋亡有明显的预防作用。实验B组和实验b组的定量检测结果经统计学分析表明 ,地塞米松对视网膜光损伤及视细胞凋亡有明显的治疗作用。结论

Objective:To investigate the preventive or curative effect of dexamethasone on retinal photic injury and optic cell apoptosis in order to study the generation mechanism of optic cell apoptosis.Methods:All Sprague Dawley rats were maintained under a cyclic light environment for 7 days. Rats were then kept in darkness for 36 hours before experimental conditions were imposed. The rats in group A were only subjected to light exposure. The rats in group B were maintained in a dark environment after 6 hours of light exposure. The rats in group A were given an interperitoneal injection of dexamethasone after dark adaptation,then exposed to white light. The rats in group B were maintained in a dark environment after 6 hours of light exposure and then given a daily interperitoneal injection of dexamethasone. All rats were fixated after irrigation and eyes were then expirated. Samples for light microscopy were processed and embedded in paraffin using routine procedures. All sections were made for HE and TUNEL,and examined under light microscopy. The area of the outer nuclear layer and the cell apoptosis index were quantified by a CIAS 1000 cell photo analysis system. The data were statistically analyzed.Results:In group A,photic injury in the retina progressively worsened and optic cell apoptosis progressively increased with increased light exposure time,then the OA(outer nuclear layer area) progressively diminished. The change in group B was like that in group A. After dexamethasone was injected,the damage in the rat retina decreased and the time period before apoptosis was found in the retina was delayed by 3 hours. The quantified results were statistically analyzed and indicated that dexamethasone could prevent and cure photic injury caused by light exposure and optic cell apoptosis.Conclusion:Dexamethasone plays an effective role in preventing and curing photic injury caused by light exposure and optic cell apoptosis in experimental rats.