Genetic Toxicity Evaluation of Iodotrifluoromethane (CFsub3I). Volume 2. Results of In Vivo Mouse Bone Marrow Erythrocyte Micronucleus Testing

Under subcontract to ManTech Environmental Technology, Incorporated, Genesys Research, Incorporated, examined the potential of odotrifluoromethane (CF3I) to induce structural chromosomes aberrations in erythropoietic cells of the bone marrow. Genesys used the mouse micronucleus test which measures the clastogenic (chromosomes breaking) action of chemicals by the induction of micronuclei in bone marrow cells, as observed in erythrocytes from the peripheral blood of male and female mice obtained approximately 24 hours after steady-state dosing. Based on preliminary toxicity information obtained by ManTech, a mouse bone marrow micronucleus test of CF3I was conducted using 2.6, 5.0, and 7.5% CF3I administered to male and female Swiss Webster mice by inhalation for six hours on each of three consecutive days. Bone marrow cells were obtained from the mice sacrificed 24 hours after the third exposure. Erythrocytes from mice exposed to the test material, and to the negative and positive controls, were evaluated for toxicity and the presence of micronuclei. The positive control, 0.4 mg triethylenemelamine (TEM)/kg (administered intraperitonealy) significantly (p<O.Ol) elevated the number of micronuclei in newly-formed erythrocytes (PCEs, polychromatic erythrocytes) from male and female mice. Toxicity of CF3I was evidenced by dose-related depression in weight for both sexes and by dose-related depressions in ratios of PCEs/1O00 erythrocytes for female mice. Significant (P