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 subsequent generation in HLG/Zte mice after exposure of the zygote stage to 1 Gy X-rays. As observed in previous studies, our results on teratogenic events occurring in the same generation, which was exposed during the zygote stage, reveal a significantly higher risk for the induction of gastroschisis. Interesting new insights came from the study of lethal and teratogenic effects in the generation obtained after mating female mice, which were exposed during their zygote stage, to unexposed males. An approximately 2-fold higher level of damage was manifest in this generation compared with controls, expressed mainly as a significant increase of prenatal mortality (P<0.01). Although there was an increase in the number of malformed fetuses on day 19 of gestation (6.5% cases of gastroschisis compared to 3.5% in the controls), the frequency of gastroschisis in the exposed group was just not statistically significant (P>0.05). These results are in line with the hypothesis that genomic instability is involved in the damage seen after radiation exposure of the zygote stage of HLG mice.