Temperature dependence of combined exposure of preimplantation mouse embryos to X-rays and mercury

Summary

Usually preimplantation mouse embryos are cultered in vitro at 37° C. In this study, mouse embryos (starting with the 2-cell stage) were incubated in vitro throughout the preimplantation period at 34°, 35°, 36°, 37°, 38° or 39° C. Embryonic development, in particular hatching of blastocysts (144 h after conception), and cell numbers (at the same time) were analysed. Embryos were exposed to X-rays (1 Gy) or to mercuric chloride (3 µM, 10 µM) or to a combination of the two agents. Control embryos developed rather well in a temperature range of 35° to 38° C. A combined risk greater than expected from the sum of the individual effects was observed only at the optimum temperature (for a combination of 1 Gy + 3 µM) or in the range of the optimum temperature, that is between 36° to 38° C (for a combination of 1 Gy + 10 µM).