Synergistic effect of vitamin C on DNA damage induced by cadmium.

Salts of divalent cadmium are well-known human mutagens and carcinogens. In the present work, the ability of vitamin C to modulate genotoxic effects of cadmium chloride on human lymphocytes was assessed using single cell gel electrophoresis (comet assay). Vitamin C at 20 and 100 micromol/l and cadmium at 5, 30 and 150 micromol/l significantly increased the tail moment of lymphocytes. Vitamin C also increased the tail moment of cells exposed to cadmium. This effect was concentration-dependent: the higher the vitamin C concentration the greater the tail moment. The combined effects of cadmium and vitamin C were more pronounced at all concentrations tested than the sum of the effects of the compounds applied separately (p < 0.05), so cadmium and vitamin C can be considered to have synergistic effects. The results obtained can be partly explained by the participation of cadmium in the Fenton reaction and reduction of its oxidized form by vitamin C.