Cytogenetic Effects in Mice after Chronic Exposure to Arsenic Followed by a Single Dose of Ethylmethane Sulfonate

The influence of a long-term treatment with arsenic (As2O3 250 mg/l in drinking water for 2-8 weeks) on the frequency of chromosome aberrations induced by a single treatment with ethylmethane sulfonate (200 mg/kg i. p.) was investigated in mice.A chronic exposure to arsenic alone induced no increase of chromosome breaks and exchanges in bone marrow cells and in spermatogonia. The effects of a single treatment with ethylmethane sulfonate are low and not statistically significant. Statistical analysis indicated that the increase of chromosome aberrations observed in bone marrow cells after the combined treatment could be due to an additive effect and not to a synergism between both substances.