A, typical DNA migration patterns of BEAS-2B cells treated with 500 μM H2O2 for 1 h at 37°C. B, tail moment (TM) representing the DNA breaks induced by H2O2 in BEAS-2B cells. Cells were exposed to H2O2 at 37°C for 1 h and then subjected to alkaline single-cell gel electrophoresis (Comet assay). Values are expressed as the means ± SD of 3 experiments carried out in duplicate (n = 3). *, **, significantly different from controls at p < 0.05 and p < 0.01, respectively (Mann-Whitney U test).