Induction of micronuclei in mouse bone marrow after combined X-rays-cyclophosphamide and X-rays-mitomycin C treatments.

The induction of micronuclei in polychromatic erythrocytes of bone marrow of Pzh:SWISS mice after combined treatment with X-rays and cyclophosphamide (CP) or X-rays and mitomycin C (MMC) were investigated. Combinations of high (1.00 Gy + 100 mg/kg bw CP and 1. 00 Gy + 5.25 mg/kg bw MMC) and low (0.25 Gy + 25 mg/kg bw CP and 0. 25 Gy + 1.75 mg/kg bw MMC) doses were used. Both chemicals enhanced the mutagenic effects caused by irradiation. After combined treatment with high doses of X-rays + CP and X-rays + MMC at different sample times increases in frequency of micronuclei were observed. Mutagenic effects were found also after treatment with two low doses, when irradiation alone produced no effects. The effects of combined treatments are generally similar to the additive effect of the single treatments. Copyright 1999 Wiley-Liss, Inc.