Teratogenic effects of ionizing radiation after exposure of preimplantation stages of mouse embryos

The mouse strain used in the experiments described does show an increase in numbers of malformations after irradiation during pre-implantation stage, though the most prominent risk clearly is mortality. Previous experiments (Pampfer and Streffer, 1988) revealed that neutrons were about 2.5 times more effective than X-rays in induction of malformations, and that the dose-response relation was of a linear-quadratic type, irrespective of the radiation quality. A common observation of all studies revealing an enhanced teratogenic risk after irradiation during the preimplantation period is that only those malformations are increased which occur already spontaneously at a certain frequency: between 0.2 and 0.7% exencephalic fetuses in Rugh's experiments (Rugh, 1969), about 14% animals with polydactyly of the forefeet in Ohzu's study (Ohzu, 1965) and between 1 and 4% fetuses with gastroschisis in our mouse strain. (author)