Cisplatin-induced lipid peroxidation and decrease of gluconeogenesis in rat kidney cortex: different effects of antioxidants and radical scavengers

Abstract

The present in vitro study was performed to investigate the effect of the nephrotoxic anticancer agent cisplatin (CP) on lipid peroxidation, on pyruvate-stimulated gluconeogenesis and on p-aminohippurate (PAH) accumulation in rat renal cortical slices. In addition, the inhibitory effects of the antioxidants and radical scavengers N,N'-diphenyl-p-phenylenediamine (DPPD), (+)-cyanidanol-3 or alpha-tocopherol on CP-induced lipid peroxidation and CP-induced decrease of gluconeogenesis and the inhibitory effect of DPPD on CP-induced decrease of PAH accumulation were evaluated. Slices were incubated in a CP-containing medium for different periods of time (7.5-300 min) and at different concentrations (0.025-1.5 mg/ml). Lipid peroxidation was monitored by measuring the production of malondialdehyde (MDA). Accumulation of PAH was expressed as slice to medium concentration ratio. Pyruvate-stimulated gluconeogenesis, measured as glucose production, was determined after a subsequent 60- or 15-min incubation in a pyruvate-containing, CP-free medium. CP led to a time- and concentration-dependent increase in MDA production, a time- and concentration-dependent decrease of pyruvate-stimulated gluconeogenesis and a time-dependent decrease of PAH accumulation in renal cortical slices. Decrease of gluconeogenesis preceded MDA production and decrease of PAH accumulation. Antioxidants reduced CP-induced MDA production and CP-induced decrease of accumulation of PAH, but did not reverse CP-induced decrease of gluconeogenesis. This might indicate, that the generation of free radicals and subsequent lipid peroxidation may play a role, at least in part, in inducing CP nephrotoxicity. There could be more than one mechanism of CP-induced nephrotoxicity, since decrease of gluconeogenesis preceded MDA production and decrease of PAH accumulation and could not be inhibited by antioxidants and radical scavengers.