Protective role of metallothionein in nickel induced oxidative damage.

Recent studies have focussed on the role of thiol rich proteins especially metallothionein (MT) in the therapeutic interventions against oxidative damage. In our previous communication we showed that reactive oxygen species arising via Fenton's reactions are the proximal lipid oxidant during nickel-toxicity. The purpose of the present communication is to evaluate the role of zinc, cadmium or silver-metallothioneins on the protection against nickel-induced peroxidative damage. Our results demonstrate that Zn-MT provided maximum protection against nickel-induced mortality in mice and also served as an efficient antagonist in inhibiting nickel-mediated lipid peroxidation compared to Cd-MT or Ag-MT. Zn-MT also provided protection against iron (II)-ascorbate induced microsomal lipid peroxidation and reversed nickel-mediated inhibition of calcium sequenstration. We conclude that Zn-MT could serve as an excellent physiological antioxidant against nickel-mediated oxidative.