Hydrogen peroxide induces necrosis, apoptosis, oncosis and apoptotic oncosis of mouse terminal proximal straight tubule cells.

Hydrogen peroxide (H2O2) has been shown to be an important mediator of ischemic and toxic tubular damage. The purpose of this study was to identify the mode of cell death observed in H2O2-exposed cultures of mouse terminal proximal straight tubule (S3) cells. H2O2 induced a dose- and time-dependent decrease in viability of S3 cells. Morphologically, S3 cells exposed to H2O2 (0.05-0.1 mM) showed features of necrosis, apoptosis, oncosis and apoptotic oncosis, whereas necrosis occurred most frequently in every experimental condition tested. On the other hand, agarose gel electrophoresis of DNA extracted from S3 cells exposed to H2O2 revealed a typical DNA ladder pattern. These data suggest that H2O2-induced proximal tubule damages are associated with the induction of various modes of cell death including necrosis, apoptosis, oncosis and apoptotic oncosis, and with the activation of endonuclease.