Up-regulated eNOS protects blood-retinal barrier in the L-arginine treated ischemic rat retina

Using immunoblot analysis and immunocytochemistry, we investigated expression and cellular localization of endothelial nitric oxide synthase (eNOS) and proliferating cell nuclear antigen (PCNA) in the l-arginine treated ischemic rat retina. In parallel, we tested whether the blood-retinal barrier was intact by immunocytochemistry using an antiserum against IgG. In the l-arginine-treated ischemic retina, the magnitude of the increased eNOS was higher, and PCNA was expressed in endothelial cells as well as in neurons in the inner retina during the whole experimental period. Finally, IgG leakage was not detectable in the l-arginine-treated ischemic retina. Our results clearly suggest that the increased NO production by eNOS may be essential for the survival of endothelial cells in the rat retina following transient ischemia.