Dimethylated arsenics induce DNA strand breaks in lung via the production of active oxygen in mice.

In order to study the genotoxicity of arsenics, we focused our attention on dimethylarsinic acid (DMAA) which was a main metabolite of inorganic arsenics in mammals. ICR mice were orally administered DMAA-Na (1500mg/kg). DNA single-strand breaks occurred specifically in lung at 12h after administration. An in vitro experiment indicated that the breaks were not caused directly by DMAA but by dimethylarsine, a further metabolite of DMAA. Furthermore, the dimethylarsine-induced breaks were diminished by the addition of SOD and catalase, suggesting that active oxygen produced by dimethylarsine was involved in the induction of DNA damage.