tert-butylhydroperoxide induces peroxynitrite-dependent mitochondrial permeability transition leading PC12 cells to necrosis

A short-term exposure of PC12 cells to tert-butylhydroperoxide, followed by recovery in fresh culture medium, causes cell death and the extent of this response progressively increases during the 120 min of posttreatment incub ation. Morphological and biochemical analyses of these cells revealed that the mode of cell death was necrosis. Cell killing induced by the hydroperox ide seems to be in part mediated by peroxynitrite because the lethal respon se was markedly and similarly reduced by the nitric oxide synthase inhibito r Nw-nitro-L-arginine methylester and by scavengers of nitric oxide or pero xynitrite. This peroxynitrite-dependent mechanism of cytotoxicity was blunt ed by antioxidants and inhibitors of mitochondrial permeability transition and the onset of cell death was preceded by mitochondrial depolarization an d loss of cellular ATP. We conclude that tert-butylhydroperoxide promotes p eroxynitrite-dependent PC12 cell necrosis causally linked to peroxidation o f membrane lipids and mitochondrial permeability transition. (C) 2001 Wiley -Liss, Inc.