Genotoxic effect induced by hydrogen peroxide in human hepatoma cells using comet assay

BACKGROUND Hydrogen peroxide (H(2)O(2)) is a common reactive oxygen intermediate generated by various forms of oxidative stress. AIM The aim of this study was to investigate the DNA damage capacity of H(2)O(2) in HepG2 cells. METHODS Cells were treated with H(2)O(2) at concentrations of 25 µM or 50 µM for 5 min, 30 min, 40 min, 1 h, or 24 h in parallel. The extent of DNA damage was assessed by the comet assay. RESULTS Compared to the control, DNA damage by 25 and 50 µM H(2)O(2) increased significantly with increasing incubation time up to 1 h, but it was not increased at 24 h. CONCLUSIONS Our findings confirm that H(2)O(2) is a typical DNA damage-inducing agent and thus is a good model system to study the effects of oxidative stress. DNA damage in HepG2 cells increased significantly with H(2)O(2) concentration and time of incubation but later decreased likely due to DNA repair mechanisms and antioxidant enzymes.