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

Introduction:Cadmium is a highly toxic heavy metal with many hazardous effects. Selenium is an essential trace element with antioxidant properties. Aim of the work: To evaluate the cadmium-induced DNA damage in rat lung cells and the possible protective role of selenium. Materials and methods: 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 (CdCl2) (1.0 mg/kg/day) for 8 weeks. Group III included rates injected intraperitoneally with sodium selenite (Na2SeO3) (0.25 mg/kg/day) for 8 weeks. Group IV included rats injected intraperitoneally with both CdCl2 (1.0 mg/kg/day) and Na2SeO3 (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). Results: In the control group, comets appeared with large bright heads and small t ails. The injection of CdCl2 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. Concomit ant administration of both cadmium and selenium resulted in a partial decrease in the DNA damage in rat lung cells indicated by decrease in D NA migration in the comet assay. Comet cells appeared with large heads and relatively small t ails compared with those of group II. A significant decrease was also observed in t ail length, tail moment, and tail% DNA compared with group II. Conclusion: CdCl2 could significantly induce DNA damage in rat lung cells. It was suggested that selenium could partially ameliorate DNA damage induced by cadmium.