Chromosomal instability in haemopoietic cells of the foetus, mother and offspring after in utero irradiation of the CBA Ca mouse

Purpose: The present study was conducted to test the susceptibility of the mouse foetus to transmit chromosomal instability to the haemopoietic stem c ells of offspring after in utero X-or plutonium-239-irradiation. Materials and methods: Pregnant CBA/Ca-mice were injected with 80 kBq/kg Pu -239 or X-irradiated with 1 Gy X-rays on days 13 or 14 of gestation. CFU-A cultures were grown from haemopoietic stem cells sampled from foetal liver and the bone marrow from the offspring and from the mother. Non-clonal, uns table chromosomal aberrations were scored in metaphases from individual ste m cell colonies. Results: The relative excess (RE) of unstable chromosomal aberrations in fo etal liver cells irradiated with I Gy X-rays increased from 1.6 at day 2 up to 2.7 at day 4 after irradiation. In the bone marrow cells from the mothe r, this value was 1.8 (average from cells sampled at days 3 and 14 after ir radiation). After injection of the pregnant mice with Pu-239, the yield of unstable chromosomal aberrations per cell was 0.14 +/- 0.03 (RE approximate ly 10) in descendants of bone marrow cells from the mother, 0.11 +/- 0.02 ( RE = 10) in descendants of foetal liver cells and 0.16 +/- 0.05 (RE = 10) i n descendants of bone marrow cells from the offspring. Conclusions: From the numerical analysis of non-clonal, unstable aberration s in haemopoietic cells from the foetus, the mother and the offspring after in utero irradiation, it was concluded that in utero irradiation of the CB A/Ca mouse was not more efficient in inducing chromosomal instability in th e offspring than in the foetus or the mother, All three cell populations ex hibited a similar degree of unstable aberrations, both in terms of the abso lute numbers of non-clonal aberrations and in terms of relative excess comp ared with unexposed controls.