Effect of selenium supplementation on the glutathione redox system in the kidney of mice after chronic cadmium exposures.

This study pertains to the role of selenium against the toxic manifestations of chronic cadmium exposure. The kidney is a recognized target organ for chronic cadmium exposure, owing to the very long half-life of cadmium. Cadmium (as cadmium chloride) in a dose of 8 mg kg-1 body wt. was administered orally for a period of 8 weeks in mice. This resulted in a significant decrease in total reduced glutathione (GSH), but the oxidized glutathione (GSSG) level showed a marked increase. This was further reflected in the GSH/GSSG ratio, which was found to be considerably lower following cadmium exposure. The two enzymes glutathione peroxidase and glutathione reductase were also assessed and it was found that there is a significant inhibition in glutathione peroxidase but glutathione reductase remained unaltered in the cadmium-exposed animals. Selenium (as sodium selenite) when supplemented in a dose of 0.35 mg kg body wt., concurrent with cadmium administration, showed improvement in the GSH level but it was still below normal values. In contrast to this, the glutathione peroxidase levels were near normal and so was the GSSG content. The level of cadmium in the animals which received cadmium and selenium simultaneously was also significantly lower when compared to that seen in the animals which received cadmium alone.