In vivo and in vitro cytogenetic damage induced by sodium nitrite

The mutagenicity of sodium nitrite was assayed by in vivo and in vitro experiments. The in vivo experiments were carried out in male rats and mice intragastrically treated twice, with an interval of 24 h, with nitrite in doses of 1.72, 5.18, 15.55 and 46.66 mg/kg body weight and in male rabbits treated with the same doses of nitrite administered daily in drinking water for 3 months. Chromosomal aberration analysis was conducted in all 3 species of animals and micronucleus induction was only evaluated in mice. Nitrite induced increases in aberrant metaphases in all 3 species of animals. Likewise, in mice it induced increases of the numbers of micronucleated polychromatic erythrocytes and a light bone marrow depression. Neither in the increases of the numbers of chromosomal aberrations nor in that of micronuclei, were dose-related responses observed. The in vitro experiments were carried out on BSC-1 and HeLa cells grown in cultures with nitrite in doses of 0.265 and 0.530 mg/ml for 24 h. Both doses produced significant increases of the percentage of chromosomal aberrations but also without demonstration of positive dose-effect relationships.