实验性光损伤大鼠视网膜病理改变的电镜观察

目的：观察实验性光损伤大鼠视网膜组织病理学特点。方法：取健康成年SD大鼠40只，随机分成正常对照组（CON）、光损伤后１天（D1）、３天（D3）、５天（D５）组，每组１０只。D1、D3、D5组大鼠采用4178Lux照度的可见光进行１２小时间歇光照射，连续３天，总计36小时，然后在正常环境中分别饲养1天、３天、５天。灌流固定，摘取眼球，制成超薄切片，应用电镜技术方法进行研究。结果：正常大鼠视网膜组织结构层次清楚，染色均匀，细胞形态规整。光照后１天，光感受器外节膜盘叠状结构解离，外核层核染色质开始固缩。光照后３天，视网膜内节线粒体肿胀，空泡性变，外核层核染色质向中心聚集，呈岛状。光照后５天，视网膜光损伤达到高峰，视网膜内、外节空泡变明显增多，外核层出现细胞核碎裂，边集，光感受器细胞内线粒体空泡变，核膜皱缩，内陷。光照后各组大鼠视网膜色素上皮、内核层及节细胞未见明显改变。结论：实验性光损伤大鼠视网膜组织病理特点是光感受器的退行性变。

An Electron Microscopy Observation of Pathologic Changes of Retina in Experimental Retinal Photo- injury Rats

Objective To observe the pathologic changes of photoreceptor cell in experimental rat retinal photo injury.Methods A light-damaged trunk was designed by ourselves.40 healthy adult SD rats were randomly divided into 4 groups by control group and 1day(D1),3 days(D3),5 days(D5)after the light-injury.The rats in Group D1,D3,D5 were given 12 hours intermittent light exposure of 4178 Lux illumination visible light for 3 days successively,36 hours in total,then they were raised in normal environment for 1day,3 days,5 days and 7 days respectively.The eyes were extracted to make ultrathin section for electronic microscopy observation.Results Normal rats have clear layers of retinal structures,stained evenly and with regular cell shape.On the 1st day after light-exposure,the outer segments of photoreceptor were arranged in a confusing order,the stack structure of retinal membrance disorganized,the outer nuclear layer nuclear chromatin began to densificate.On the 3rd day,in the inner segments,mitochondrial swelling and vesiculation,the cell nuclear chromatin gathered toward the center with the island shape.On the 5th day,the retinal light injury reached its peak:the vesiculation on inner and outer segments could be seen everywhere,the cell nuclei were disorganized,mitochondrial vesiculation in photoreceptor cell emerged,nuclear membrance shrank and sank inward.No obvious changes could be seen on the retinal pigmental epithelium,the inner nuclear layer and the layer of ganglionic cells.Conclusion The photoreceptor cell degeneration is the pathologic characteristic of experimental rat retinal photo injury