Protective effect of selenium against arsenic-induced chromosomal damage in cultured human lymphocytes

Combined effects of Na2SeO3 and NaAsO2 were studied on the chromosomes of cultured human lymphocytes. The cells were exposed to selenium and/or arsenic for 48 hours, and the total culture time was 72 hours. Two arsenic concentrations were combined with three different selenium concentrations. Arsenic produced increased frequencies of chromosomal aberrations, while selenium had a modest clastogenic effect. Selenium was found to reduce the frequency of gaps and chromatid breaks induced by arsenic, while no certain effect on the frequency of chromosome breaks was observed. The reducing effect of selenium was smaller when the cells were exposed to a higher arsenic dose.