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

Background: Hydrogen peroxide (H₂O₂) 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 H₂O₂ in HepG2 cells. Methods: Cells were treated with H₂O₂ at concentrations of 25 mM or 50 mM 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 mM H₂O₂ increased significantly with increasing incubation time up to 1 h, but it was not increased at 24 h. Conclusions: Our findings confirm that H₂O₂ 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 H₂O₂ concentration and time of incubation but later decreased likely due to DNA repair mechanisms and antioxidant enzymes.