Apoptotic Cell Death in Experimental Retinal Vein Occlusion

ABSTRACT

We used an animal model of laser-induced retinal vein occlusion to study the temporal and spatial patterns of neuronal necrosis and apoptosis. After photodynamic retinal vein thrombosis with argon-green laser, rats were sacrificed at 6 hours, 12 hours, 1 day, 2 days, 3 days, 5 days, 7 days, and 14 days after vein occlusion. The temporal and spatial patterns of neuronal cell death were determined using light and electron microscopy, TdT-dUTP nick-end labeling[TUNEL]and DNA gel electrophoresis. The cells in retinal ganglion cell layer and inner nuclear layer showed both necrotic and apoptotic changes 12 hours after vein occlusion. The TUNEL positivity were detected at day 1 after vein occlusion and the number of positive cell increased until day 2, and decreased thereafter. DNA ladder pattern was observed 48 hours after vein occlusion by DNA gel electrophoreisis. These data demonstrated that retinal vein occlusion induces necrosis and apoptosis in the retinal ganglion cell and inner nuclear layer.