Suppressive effect of aspirin on chromosome aberration induced by mitomycin C in mice.

Chromosome aberrations induced by mitomycin C (MMC) were suppressed by aspirin in a mouse micronucleus test with peripheral blood and bone marrow cells. Aspirin at doses of 0.5, 5, and 50 mg/kg was injected intraperitoneally or per administered orally 0.5, 6, or 24 h after administration of MMC and then peripheral blood and/or bone marrow cells were sampled 48 h after administration of MMC. The suppressive effect of aspirin was more pronounced in the aspirin-treated groups 24 h than 0.5 and 6 h after administration of MMC. In the aspirin-treated group at 24 h, the frequency of polychromatic erythrocytes with micronuclei was decreased by about 60-80% after intraperitoneal injection and by about 40-70% after oral administration. It is suggested that aspirin may directly act on MMC metabolites, but not on MMC itself.