Bioenergetics and DNA alteration of normal human fibroblasts by hexavalent chromium.

The effects of hexavalent chromium on mitochondria of normal human fibroblasts were investigated through the measurement of oxygen consumption, and its genotoxic effect through the analysis of chromium DNA adducts and oxidative DNA lesions. ROS production was also quantified. Chromium diminished oxygen consumption by cells in a concentration-dependent manner (IC(50)=66±8μM). This effect can be attributed to an alteration in mitochondrial functions, leading to defective glucose catabolism. The Comet assay, performed with and without the lesion-specific enzyme formamidopyrimidine-DNA glycosylase (Fpg), highlighted the extent of oxidative DNA base damage. DNA base damage was induced with low concentrations (0.5-3μM) of Cr(VI), whereas bioenergetic disturbance was only observed at higher concentrations (20-500μM).