Lethal and teratogenic effects in two successive generations of the HLG mouse strain after radiation exposure of zygotes - association with genomic instability?

We analysed the transmission of lethal and teratogenic events to the subseq uent generation in HLG/Zte mice after exposure of the zygote stage to 1 Gy X-rays. As observed in previous studies, our results an teratogenic events occurring in the same generation, which was exposed during the zygote stage , reveal a significantly higher risk for the induction of gastroschisis. In teresting new insights came from the study of lethal and teratogenic effect s in the generation obtained after mating female mice, which were exposed d uring their zygote stage, to unexposed males. An approximately 2-fold highe r level of damage was manifest in this generation compared with controls, e xpressed mainly as a significant increase of prenatal mortality (P < 0.01). Although there was an increase in the number of malformed fetuses on day 1 9 of gestation (6.5% cases of gastroschisis compared to 3.5% in the control s), the frequency of gastroschisis in the exposed group was just not statis tically significant (P > 0.05). These results are in line with the hypothes is that genomic instability is involved in the damage seen after radiation exposure of the zygote stage of HLG mice. (C) 1999 Elsevier Science B.V. Al l rights reserved.