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

Using immunoblot analysis and immunocytochemistry, we investigated expressi on and cellular localization of endothelial nitric oxide synthase (eNOS) an d proliferating cell nuclear antigen (PCNA) in the L-arginine treated ische mic rat retina. In parallel, we tested whether the blood-retinal barrier wa s intact by immunocytochemistry using an antiserum against IgG. In the L-ar ginine-treated ischemic retina, the magnitude of the increased eNOS was hig her, and PCNA was expressed in endothelial cells as well as in neurons in t he inner retina during the whole experimental period. Finally, IgG leakage was not detectable in the L-arginine-treated ischemic retina. Our results c learly suggest that the increased NO production by eNOS may be essential fo r the survival of endothelial cells in the rat retina following transient i schemia. NeuroReport 12:2405-2409 (C) 2001 Lippincott Williams & Wilkins.