Induction of DNA damage by free radicals generated either by organic or inorganic arsenic (AsIII, MMAIII, and DMAIII) in cultures of B and T lymphocytes

The aim of this work is based in the premise that inorganic arsenic (As^III) and trivalentmethylated metabolites monomethylarsonous (MMA^III) and dimethylarsinous (DMA^III) participate in DNA damage through the generation of reactive oxygen species (ROS). We have utilized two lymphoblastic lines, Raji (B cells) and Jurkat (T cells), which were treated with the trivalent arsenic species (dose: 0–100 μM) and analyzed by two assays (comet assay and flow cytometry) in the determination of DNA damage and ROS effects in vivo. The results showed that the damage to the DNA and the generation of ROS are different in both cellular lines with respect to the dose of organic arsenic, and the order of damage is MMA^III>DMA^III>As^III. This fact suggests that the DMA^III is not always the more cytotoxic intermediary xenobiotic, as has already been reported in another study.