Effect of L1 on iron/hydrogen peroxide–induced DNA single-strand breaks. Iron-loaded HepG2 cells were incubated in 1 mmol/L L1 for 1 hour, followed by exposure to 100 μmol/L hydrogen peroxide for 30 minutes. Shown are DNA strand breaks in control cells exposed to media alone, iron-loaded cells exposed to hydrogen peroxide, and iron-loaded cells exposed to L1 before exposure to hydrogen peroxide. The results are the mean ± SEM of four experiments performed in duplicate (*P < .03 compared with iron-loaded cells exposed to hydrogen peroxide).