ABSTRACT
Heavy metals are important occupational and environmental pollutants that cause damage to various organs. Although there is no effective therapy for such a poisoning, metallothionein has been shown to play a key role in the detoxification of cadmium [Cd]. Evidence in the literature suggests that superoxide dismutase, glutathione peroxidase, and catalase constitute important defense mechanisms against oxygen toxicity in the cells. The aim of this study was to investigate the effect of cadmium chloride and Pb-acetate on antioxidant enzymes in the human skin fibroblast cells [HF2FF]. The human skin fibroblast [HF2FF] cells were incubated in serum-free medium containing 20 pM CdCI[2] for 18 hr three times a week. The same exposure to an equimolar dose of Pb-acetate was performed, After each exposure and after three times exposure the cells were collected and cell viability, the contents of superoxide dismutase [SOD], catalase, glutathione peroxidase [GSH-Px], GSH and malondialdehyde [MDA] were measured. Cd caused cytotoxicity and inhibition of glutathione peroxidase [GSH-Px] and SOD activity, as well as depletion of the reduced form of glutathione [GSH] in the cell. The level of lipid peroxidation [LP] was increased, but catalase activity was not significantly altered. These defects were increased with repeated exposures. The same exposure to an equimolar dose of Pb-acetate evoked only inhibition of GSH-Px and SOD. The values of GSH, catalase and LP activity remained unchanged. The inhibition of GSH-Px and SOD may be considered as an important biomarker of the toxic effect of metals