Alterations of cellular redox homeostasis in cultured fibroblast-like renal cells upon exposure to low doses of cytochrome bc1 complex inhibitor kresoxim-methyl.

In this paper we elucidate the effects of the cytochrome bc1 inhibitor, strobilurin fungicide kresoxim-methyl, on the redox balance of a mammalian renal cell line. To explore whether mammalian exposure to sub-nephrotoxic concentrations of kresoxim-methyl induces cellular and biochemical mechanisms of toxicity, its effects on cellular viability and, in particular, several parameters related to oxidative stress, mitochondrial respiratory function and apoptosis were examined in fibroblast-like renal Vero cells. Elevation of mitochondrial superoxide generation, together with a concomitant decrease in mitochondrial transmembrane potential was indicative of mitochondrial dysfunction. Losses on antioxidant enzyme activities and GSH, along with increased H2O2 and nitrite release were associated with oxidative stress and induced impaired cellular migration. Raise of intracellular calcium was also observed, while no experimental evidence of apoptosis was found. Our findings suggest that sub-nephrotoxic concentrations of kresoxim-methyl cause perturbation of multiple pathways in renal mammalian cellular redox homeostasis.