PEROXYNITRITE CYTOTOXICITY ON BOVINE RETINAL PIGMENTED EPITHELIAL-CELLS IN CULTURE

Peroxynitrite induced in vitro a dose dependent toxicity on retinal pi gmented epithelial (RPE) cells. Cell death was partially mediated by a poptosis as demonstrated by nuclear fragmentation and TdT-mediated dUT P nick-end labeling assay. Peroxynitrite-induced tyrosine nitration wa s revealed by immunocytochemistry, both in the cytoplasm and in the nu cleus of the cells. Nitration was not observed in RPE cells, producing nitric oxide (NO) after stimulation by lipopolysacharide and interfer on-g (IFN-gamma), suggesting that peroxynitrite was not formed in vitr o in such conditions. Peroxynitrite could be responsible for the retin al damages observed in pathological conditions in which NO has been de monstrated to be involved. In this context, EGb761, identified as a fr ee radical scavenger, was showed herein to protect RPE cells against p eroxynitrite injury. (C) 1996 Academic Press, Inc.