Genotoxicity of cadmium in rat lung cells assessed by an alkaline comet assay and the possible protective role of selenium

ABSTRACT

Cadmium is a highly toxic heavy metal with many hazardous effects. Selenium is an essential trace element with antioxidant properties. To evaluate the cadmium-induced DNA damage in rat lung cells and the possible protective role of selenium. Thirty-six adult male albino rats were used in this experiment. They were divided into four equal groups. Group I was the control group. Group II included rates that were injected intraperitoneally with cadmium chloride [CdCl[2]] [1.0 mg/kg/day] for 8 weeks. Group III included rates injected intraperitoneally with sodium selenite [Na[2]SeO[3]] [0.25 mg/kg/day] for 8 weeks. Group IV included rats injected intraperitoneally with both CdCl[2] [1.0 mg/kg/day] and Na[2]SeO[3] [0.25 mg/kg/day] for 8 weeks. At the end of the experiment, the lungs of rats were taken and processed for single-cell gel electrophoresis [comet assay]. In the control group, comets appeared with large bright heads and small tails. The injection of CdCl[2] in group II induced DNA damage in rat lung cells, indicated by increased migration in the comet assay. Comet cells appeared with small heads and long tails. Statistically, there was a significant increase in tail length, tail moment, and tail% DNA compared with the control. Injection of selenium alone did not show any difference from the control. Concomitant administration of both cadmium and selenium resulted in a partial decrease in the DNA damage in rat lung cells indicated by decrease in DNA migration in the comet assay. Comet cells appeared with large heads and relatively small tails compared with those of group II. A significant decrease was also observed in tail length, tail moment, and tail% DNA compared with group II. CdCl[2] could significantly induce DNA damage in rat lung cells. It was suggested that selenium could partially ameliorate DNA damage induced by cadmium