Nephrotoxicity is one of the main side effects of the anticancer drug cisplatin, and one of its main therapeutic limitations. It has been suggested that p53 activation plays important roles in renal cell injury by cisplatin. However, the mechanism of p53 activation by cisplatin is unclear. This study examined whether reactive oxygen species (ROS) production by cisplatin would be linked to p53 activation in rat mesangial cells.Renal cells were incubated with cisplatin in the absence or presence of pifithrin-a (PFT), N-acetyl-cysteine (NAC), or dimethylthiourea (DMT). Cell viability was evaluated by 3-(4,5-dimethyl-2-thiazol yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Apoptosis was evaluated by caspase-3 activity and cleavage of poly (ADP-ribose) polymerase (PARP). The relative levels of ROS and p53 phosphorylation were determined by fluorometric assay and Western blot analysis, respectively.Cisplatin induced apoptotic cell death via caspase-3 activation and PARP cleavage, and also increased p53 activation and ROS production. The p53 inhibitor PFT inhibited cisplatin-induced apoptosis. NAC and DMT, two antioxidants, also inhibited cisplatin-induced apoptosis. Interestingly, NAC and DMT reduced ROS production and suppressed p53 activation in renal cells exposed to cisplatin.Our results suggest that the ability of cisplatin to induce apoptosis of rat mesangial cells requires ROS-dependent p53 activation, thus, supporting the potential therapeutic role of antioxidants in preventing the cisplatin nephrotoxicity.