ABSTRACT
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