The combined treatment of preimplantation mouse embryos cultured in vitro with X-rays and 2,4-dinitrophenol

Mouse embryos have been isolated in the late G 2-phase of 2-cell stage (30 h p.c.) medium. Subsequently the embryos have been cultivated until 144 h p.c. in vitro. The following variables have been determined: The microscopic visible development; the number of cell nuclei at different stages of development; the number of hypoploidic and hyperploidic cell nuclei; the number of micronuclei. First of all the effects of X-rays and DNP applicated singly have been investigated by their influence on the cell number 48 h p.c. and the amount of hatched blastocysts 144 h p.c. In the first combination experiment the embryos have been irradiated with 100 R X-rays and transferred immediately after irradiation to a culture medium containing 10 μM DNP; a concentration which does not influence embryological development at the investigated period. 24 hours after the start of the DNP-treatment the embryos are washed and transferred to a DNP-free medium. In a final series the subsequent experiments have been performed in a protein-free medium. Additionally, glucose has been omitted from the medium in order to minimize ATP-production by glycolyis. It has not been possible to find an effect different from additivity, when X-rays and DNP are administered jointly under various experimental conditions. Therefore, the original hypothesis, that DNP might enhance damage induced by X-rays, cannot be proved. (orig./MG)