兔视网膜倍频532 nm 激光损伤组织形态学研究

摘要

AIM: To observe histopathology changes of spot regional in chinchilla rabbit's retina at different periods after frequency-doubled 532nm laser irradiation. METHODS: Twenty healthy rabbits were randomly divided into two groups: 16 in group A ( laser group ) and 4 in group B (normal control group).According to different time after laser photocoagulation rabbits were divided into four subgroups: 1d, 1 week, 2 weeks, 1month, group A with 4 for each subgroup;group B with 1 for each subgroup. To observe the histopathologic changes we used fundus photograph, light microscope, electron microscope and spot diameter calculating in different time points. RESULTS: ( 1 ) Fundus photography: the spot region changed from thick white edema appearance on 1d after the surgery to melanoma attachment by 1 month; ( 2 ) Light microscopy: the main damage spot region was concentrated in the outer retina after photocoagulation. Photoreceptor cell appeared necrosis and apoptosis. With the passage of time, glial cells, pigment cells filled injury regional, and fibrous proliferation was formed;( 3 ) Electron microscope: after photocoagulation, structure of membranous disc blurred and arranged in disorder; mitochondrial cristae became vague, fracture or even disappear; obvious vacuolization appeared.It began to appear apoptosis after 1 week, and gradually the fibroblast proliferation appeared; ( 4 ) Spot size: the spot size was the maximum at 1d, then gradually became smaller, spot size down to 85% at one-week time, 80%at 2-week time, and 79%at one-month time. CONCLUSION: Frequency -doubled 532nm laser irradiation of pigmented macular, spot reaction is most obvious at 1d and stabilized at about 2 weeks.%目的：通过倍频532 nm激光照射青紫蓝兔眼底，观察不同时期视网膜光斑区域组织形态学改变。　　方法：健康青紫蓝兔20只随机分为A组16只（激光损伤组）和B组4只（正常对照组），使用倍频532 nm激光照射A组兔视网膜（光斑大小200μm，脉宽0．05s，光斑TsoⅢ），B组未行光凝。按激光光凝术后不同时相点：1d；1，2 wk；1 mo观察眼底照片的改变、光镜下组织形态学改变、电镜下超微结构的改变及光斑直径在不同时相点的变化。　　结果：（1）眼底照相：随时间推移，光斑由术后1d时的浓白色水肿外观变为术后1mo时的黑色素附着区域；（2）光镜观察：光凝后光斑区域主要损伤集中在视网膜外层，光感受器细胞坏死、凋亡，随时间推移，胶质细胞、色素细胞充填损伤区域，形成纤维增殖；（3）电镜观察：光凝后出现明显的视细胞外节膜盘结构模糊，排列紊乱，线粒体嵴模糊、断裂甚至消失，明显的空泡样变，术后1 wk开始即出现细胞染色质集边等凋亡改变，后期胶原纤维增殖；（4）光斑大小：光斑大小从术后1d时的最大值随时间推移，逐渐变小，术后1 wk时光斑大小缩小15％，术后2 wk时光斑大小缩小20％，术后1 mo时光斑大小缩小21％。结论：倍频532 nm激光照射青紫蓝兔黄斑区，光斑反应术后1 d时最为明显，至术后2 wk左右基本稳定。