纤溶酶致人眼玻璃体后脱离的实验研究

目的 探讨人眼用纤溶酶致玻璃体后脱离(posterior vitreous detachment, PVD)的剂量、效果，对细胞活性的影响及其作用机制。 方法 死亡后24 h内的尸体眼共20只，随机分为4组。分别于平坦部注入1，2，3 U的纤溶酶以及0.1 ml的平衡盐溶液(balanced salt solution, BSS)作为对照。用光镜和透射电镜进行形态学观察；免疫电镜进行视网膜内界膜上纤连蛋白（laminin，LN）、层粘连蛋白（fibronectin，FN）的定量分析；流式细胞仪测定视网膜细胞活性。 结果 注入纤溶酶后，玻璃体胶原与内界膜附着减弱，随纤溶酶注入的增加，效果增强；LN(3 U组,P＜0.05)、FN(2 U、3 U组，P＜0.05)在内界膜上的含量减少;形态上及细胞存活数量与对照组无明显差别。 结论 适当剂量的纤溶酶 注入玻璃体腔，可降解FN、LN，促进玻璃体胶原与内界膜的分离，导致PVD，而对视网膜形态及细胞活性无明显影响。 （中华眼底病杂志，2003，19：42-45）

Experimental study of posterior vitreous detachment with plasmin in human eyes

Objective To investigate the dosage, efficacy and safety of intravitreal injection of plasmin in producing posterior vitreous detachment (PVD), and the possible role of plasmin in degrading adhesion glycoproteins of inner limiting membrane (ILM). Methods Twenty eyes of young human cadavers within 24 hours after death were divided into 4 groups that received 0 1 ml balanced salt solution (group 1) as control, 1 (group 2), 2 (group 3), or 3 (group 4) U of human plasmin. Optical and transmission electron microcopies were performed to examine the ultrastructure of the vitreoretinal interface. Electron immunocytochemical techniques were carried out on ILM to estimate the content of fibronectin (FN) and laminin (LN). Flow cytometry was used for cell viability analysis of variance (ANOVA) and Tukey test was employed for statistical analysis. Results Microscopy demonstrated that plasmin especially in group 4 cleaved the attachment of the vitreous collagen fibrils to the ILM with no evident damage to the inner retina. The content of LN, FN in ILM decreased with injection of plasmin (group 3 and 4 had statistical significance from control group for FN, P <0.05; for LN in group 4, P< 0.05). Retinal cell viability was similar for plasmin treated and control eyes. Conclusion Human plasmin disrupts the attachment of posterior hyaloid to the ILM with no morphologic changes of the inner retina. PVD is induced mostly with injection of 3 U plasmin.