role of streptokinase in induction of posterior vitreous detachment: a scanning and transmission electron microscopic study of the retina in rabbits

The study was conducted to evaluate the possibility of inducing posterior vitreous detachment [PVD] by intravitreal injection of Streptokinase using scanning and transmission electron microscopic, and electrophysiological study. The present study was performed on thirty eyes of fifteen male white rabbits. The rabbits were divided into three equal groups. The right eye of the 3 groups received intravitreal injection of Streptokinase at three different concentrations [150,1500 and 15000 IV in 0.1 mL balanced salt solution [BSS]] in the- midvitreous cavity. The left eye in all animals received intravitreal injection of BSS and were considered as control group. Electroretinograph [ERG] was performed one hour, one day and one week following injection. The rabbits were killed after ten days and the enucleated eyes were processed for transmission and scanning electron microscopic examination. In group I, scanning electron microscopy showed the retinal surface covered with thin collagen fibers, while in group II, complete PVD with bare retinal surface was seen. Group III showed a bare retinal surface with hemorrhagic reaction and toxic effects on the retina by transmission electron microscopy. ERG findings are discussed. Intravitreal injection of 1500 IU of Streptokinase can lead to PVD without major toxic effects on the retina