人视网膜激光光凝后荧光血管造影和超微结构研究

Flourescein Angiography and Ultrastructure Studies on Retina after Laser Photocoagulation

目的 探讨激光对人视网膜损伤后荧光血管造影和超微结构改变及修复过程 ,为激光治疗视网膜病变提供理论基础。方法 因眼眶恶性肿瘤需作眶内容物剜出的 7例病人 ,征得合作和签署同意书后 ,术前 1、3和 7d用 、 、 级光斑光凝视网膜 ,分别于 1、3和 7d行眼底血管荧光造影照像。摘除眼球用 2 0 g/ L 多聚甲醛固定 ,作成超薄切片 ,透射电镜观察照像。结果 荧光血管造影 :光凝后第 1d可见荧光明显渗漏 ,光斑越大 ,渗漏越显著。光凝后第 3d渗漏减轻 ,中心出现小的遮蔽荧光。光凝后第 7d渗漏消失 ,中心区遮蔽荧光增强。超微结构 :光凝后第 1d, 级光斑 ,部分色素上皮细胞肿胀、坏死 ,部分感光细胞排列紊乱或溶解消失 ,外核层细胞数减少。 级光斑 ,色素上皮和感光细胞大量溶解破坏 ,外核层部分细胞坏死核凋亡 ,外网状层结构紊乱。 级光斑 ,视网膜全层受损。光凝后第 3d,细胞水肿减轻 ,碎屑减少 ,吞噬细胞出现 ,色素上皮细胞和 Müller细胞开始增生。光凝后第 7d,增生的色素上皮细胞和 Müller细胞修复视网膜破坏区。 至 级光斑视网膜结构紊乱逐渐加重。结论 光疑引起视网膜荧光渗漏、视网膜色素上皮细胞、神经元细胞的坏死和凋亡 ,全层超微结构的破坏 。

Objective The fluorescein angiographs and ultrastructure changes as well as the repairable process of retina after photocoagulation were analyzed to provide scientific basis for the rationale of using laser in the treatment of retinal lesions. Methods Normal retinae were coagulated using Ⅰ,Ⅱ,Ⅲ grade photic spots and were exposed to fluorescein angiography 1,3,7 days before the necessary exenteration in conformity with the informed consent given by 7 patients with malignant tumor of orbit.The retina from the removed globe was cut into thin sections and observed by use of electron microscope. Results Fluorescein angiography: Fluorescein leaked in photic spots 1 day after photocoagulation. Leakage relieved with central small fluorescein block 3 days after photocoagulation. Leakage disappeared with central fluorescein block 7 days after photocoagulation. Ultrastructure: 1 day after photocoagulation, Ⅰgrade photic spot, some retinal pigment epithelium(RPE) cells were swellen and necrotic. Partial photoreceptors were lysed and disarranged. Cells of outer nuclear layer decreased in number.Ⅱgrade photic spot, RPE and photoreceptors were destroyed. Some necrotic and apoptotic cells appeared in the outer nuclear layer. Structure of outer plexiform layer became disorganized. Ⅲ grade photic spot, retina was destroyed severely. 3 days after photocoagulation,cell edema and debris decreased. Phagocytes appeared. RPE and Müller cells started proliferation. 7 days after photocoagulation, proliferative RPE and Müller cells replaced the damaged areas of the retina. Retinal structure disorganization increased gradually from Ⅰto Ⅲ spot. Conclusion Photocoagulation caused fluorescein leakage of retina, apoptosis of RPE and neuron, and damage to other structure. Subsequently, the proliferous RPE and Müller cells repaired the destroyed areas of retina.