[Influence of actinomycin D or ethidium bromide on the radiation risk in embryos of mice in the preimplantation stage in vitro].

The authors examined if the radiation risk (after X = irradiation with 0.94 Gy or 3H-thymidine treatment with 0.5 kBq/ml) in embryos of mice of the preimplantation stage in vitro is increased by the presence of actinomycin D (0.3 nM for 112 hours or 100 nM for 90 minutes) or ethidium bromide (0.5 microM for 112 hours). The influence of these substances on the radiation effect was determined by microscopic observation of the development of embryos and by investigation of the cell proliferation. The radiation risk was regarded to be increased if the combined effect was significantly higher than the total amount of the individual effects. The radiation risk for the morphologic development of the embryos was significantly increased by actinomycin D; the combined effects were about 1.3 times higher than the total amount of the individual effects. There was no increased risk for the cell proliferation. Ethidium bromide did not modify the radiation risk neither with respect to the morphologic development nor regarding the cell proliferation.