实验性大鼠视网膜光损伤模型的建立与研究

目的：建立和研究视网膜光损伤动物模型，观察较强可见光对大鼠视网膜光损伤的病理变化。方法：自制光损伤箱。取健康成年SD大鼠35只，随机分成正常对照组（CON）、光损伤后1d(D1)、3d(D3)、5天（D5）、7d((D7)组，每组7只，各组大鼠在12h明12h暗环境中饲养7d，然后暗适应36h。D1、D3、D5、D7组大鼠采用4178Lux照度的可见光进行12h间歇光照射，连续3d，总计36h，然后在正常环境中分别饱饲养1d、3d、5d和7d。大鼠以10％水合氯醛麻醉，分别用4％多聚甲醛液3％戊二醛灌流固定，摘取眼球，制成石蜡切片及超薄切片，应用光谱、电镜观察。结果：正常大鼠视网膜组织结构层次清楚，内、外节视杆排列整齐、规则。内、外核层排列紧密，染色均匀。光照后各组均可见光感受器形态的变化，其变化随着时间的延长而加重。D7组变化与D5组基本相似。主要变化为外核层变薄而稀疏。光感受器视杆外节排列紊乱，膜盘叠状结构解离。内节线粒体肿胀，空泡变。外核层细胞核染色质固缩，分布不均匀，向中央聚集。结论：采用4178Lux照度的可见光较长时间（36h)间歇照射可诱导大鼠视网膜光损伤，成功地摸拟了大鼠视网膜光损伤模型；在光损伤的早期，即出现光感受器形态的变化，并随着时间的延长损伤逐渐加重。

The Establishment of Rat Model in the Experimental Retinal Photo- injury and Research on its Retinal Pathologic Changes

Objective To establish and study the better animal models of the retinal photic injury and to observe the pathologic changes of the retinal injury in rats under strong visible light. Methods A light-damaged trunk was designed by ourselves. 35 healthy adult SD rats were randomly divided into the control group (CON) and 1 day(D1), 3 days(D3),5 days(D5)and 7 days(D7)groups after the light-injury. The rats in each group were given an intermittent light exposure for 7 days, 12 hours light exposure every day and 12 hours dark-adaptation before every exposure. Then they were given 36 hours dark-adaptation. The rats in Group D1, D3,D5 and D7 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 1,3 and 5 days and 7 days respectively. Afterwards, all the rats in each group were anesthetized with 10% chloral hydrate. The eyes were extracted to make retinal paraffin and ultrathin sections for light and electronic microscopy observation. Results Normal rats have clear layers of retinal structures. The inner and outer segments were in a neat and orderly arrangement, and the inner and outer nuclear layer arranged in sequence, stained evenly. Morphological changes of receptors appeared in groups D1,D3,D5 and D7,and deteriorated gradually along with the progression of light exposure. The changes in group D7 are generally similar to those in group D5. The main changes are as follows. The outer nuclear layer became thinner and sparser. The outer segments of optic rods of photoreceptors arranged in a confused order, the stack structure of membranous disks disorganized. The mitochondria in the inner segments of optic rods swelled and vesiculated. The nuclear chromatin in the outer nuclear layer gathered toward the center with the uneven distribution. Conclusion Long time (36 hours) intermittent light-exposure of 4178 Lux illumination of visible light could lead to retinal photic injury in rats, which successfully imitated the retinal photic injury in rats. In the early stage of photic injury, the morphological changes of photoreceptors came into sight. Along the time progression, the retinal photic injury became gradually more serious.