Generation of DNA single-strand breaks in iron-loaded HepG2 cells exposed to hydrogen peroxide. Iron-loaded cells were exposed to 100 μmol/L hydrogen peroxide for 30 minutes. Cells were harvested and DNA single-strand breaks were quantified by alkaline elution. Shown are DNA strand breaks in control cells exposed to media alone (□), iron-loaded cells (•), hydrogen peroxide–exposed cells, and iron-loaded cells exposed to hydrogen peroxide. The results are the mean ± SEM of three experiments performed in duplicate (*P< .03 compared with hydrogen peroxide exposed cells).