Abstract
Abstract: :
Purpose: To evaluate the efficacy of intravitreal rt-PA in promoting patency of the vessels and resolution of intraretinal hemorrhages in photochemically induced retinal vein occlusion in rabbits. Methods: Occlusion of the retinal veins was performed by photothrombosis, using the rose Bengal dye intravenously and the green Nd-YAG laser, of 532 nm wavelength. Fluorescein angiography and electron microscopy were performed in 12 eyes, immediately after the occlusion, to correlate the morphologic alterations with clinical observations. Another 62 rabbits eyes with retinal vein occlusion confirmed by fluorescein angiography were randomly selected, in double-blind, to intravitreal injections of 50µg of rt-PA or balanced saline solution (BSS). Fluorescein angiography was repeated on days 1, 4, 7, 15, and 30 after intravitreal injection. Results: Retinal vein occlusion was confirmed in the 12 eyes in which fluorescein angiography and electron microscopy were performed. In the 62 intravitreal injected eyes, there was no statistic difference between rt-PA and BSS in promoting patency, assessed by fluorescein angiography. The resolution of intraretinal hemorrhages was significantly increased by intravitreal rt-PA (p<0.001). Conclusion: Intravitreal rt-PA did not result in the re-establishment of retinal veins perfusion, but it did increase the intraretinal hemorrhage resolution in this photochemically induced retinal vein occlusion model in rabbits.
Keywords: 554 retina • 390 drug toxicity/drug effects • 629 vitreous