Transplacental effect of stobadine on cyclophosphamide induced micronucleus frequency in mice.

The transplacental effect of stobadine (STB) on micronucleus (MN) frequency was studied in fetuses of ICR mice injected with cyclophosphamide (CP). STB, dissolved in methylcellulose, was administered orally from gestational day 11 until day 17 in two concentrations (23.6 and 70.07 mg/kg body wt) 2 h prior to CP administration (i.p., 10 mg/kg body wt). In fetal liver and in maternal bone marrow the frequencies of MN in polychromatic erythrocytes were significantly decreased in both STB-pretreated groups injected with CP compared to the CP group pretreated with methylcellulose. The higher concentrations of STB was more efficient, but the difference was not significant. In the CP-treated groups, fetal MN frequencies were about three times higher than in maternal bone marrow. Mouse fetuses thus proved to be far more susceptible to the clastogenic effect of CP. The protective effect of STB against CP mutagenicity was confirmed in fetuses of CP-treated female ICR mice. These results are discussed with respect to fetal development and maternal/fetal metabolism.