Clastogenic effects of transplacental exposure of mouse embryos to nitrogen mustard or cyclophosphamide.

Embryos from day 12 pregnant Swiss mice given intraperitoneal injections of nitrogen mustard (HN2) or cyclophosphamide (CP) were evaluated for chromosomal aberrations. Both agents induced dose-dependent increases in the frequency of cells with aberrations observed in embryos from females treated 6 hr before sacrifice. The highest frequencies of cells with aberrations were observed when females were injected 15 or 18 hr before sacrifice on day 12. A teratogenic dose of HN2 (1.0 mg/kg) induced significantly higher frequencies of damaged cells than a teratogenic dose of CP (20 mg/kg). Cytogenetic analysis of rodent embryos from pregnant females exposed to xenobiotic agents may be an effective screening test for evaluation of genetic effects induced by transplacental exposure.