猫视网膜脱离后光感受器细胞形态学改变

为观察猫视网膜脱离后光感受器细胞形态学变化 ,2 8只猫分为实验组和对照组 ,利用微穿刺技术将 0 2 5 %Healon注入到视网膜下腔造成视网膜脱离。脱离后 0 5～90天的视网膜加工成组织切片 ,用于光镜和电镜观察。结果显示 ,视网膜脱离 2 4h,光感受器外节出现膨胀和破裂 ,内节和细胞体损害轻微。脱离后 3～ 1 4天 ,大多数内节出现空泡、线粒体肿胀和嵴的断裂。细胞胞体出现内质网膨胀、线粒体退化以及多囊小体形成。脱离后 1～3个月 ,外核层细胞体之间出现大量空泡或腔隙。某些光感受器胞体出现细胞浆膜破裂 ,胞浆物质和小细胞器丢失。这种改变在视网膜高脱离区比浅脱离区更明显 ,并随脱离时间的延长呈渐进性加重。研究表明 ,视网膜脱离能诱发光感受器细胞发生退行性改变 ,其程度与视网膜脱离的高度和时间有关

MORPHOLOGICAL CHANGES IN PHOTORECEPTOR AFTER RETINAL DETACHMENT IN CATS

To observe the morphological changes in photoreceptor after experimental retinal detachment in cats. Twenty eight cats were divided into experimental group and control group. Retinal detachment was produced by injecting 0 25% solution of Healon into the subretinal space with the aid of a micropipette. Histologic sections of retina were processed for light and electron microscopy at detachment intervals ranging from 0 5 days to 3 months. At 24 hours postdetachment, the outer segments were distended and disrupted, but the inner segments and photoreceptor cell bodies were only slightly affected. 3-14 days after detachment, the inner segments were affected at multiple sites, albeit to varying degrees. Some of them were vacuolizated at the tip, with mitochondria swollen and cristae fragmented. At the same time, the photoreceptor cell bodies often showed a distension of endoplasmic reticulum, deterioration of mitochondria, and the presence of multivesicular bodies. 1-3 months after detachment, large empty spaces in the outer nuclear layer and a progressive loss of cytoplasmic ground substance and organelles appeared in some photoreceptors as detachment duration lengthened. Necrosis of the inner segments and cell bodies were more marked in the more serious detachment than those in shallow ones. Degenerative changes occured in the photoreceptor very soon after experimental retinal detachment, and these changes were correlated with both the depth and duration of retinal detachment.