The development potential of ethanol-induced monosomic and trisomic conceptuses in the mouse

The development potential of fertilized embryos isolated from female mice previously given a single dose of either a dilute solution of ethanol or distilled water (controls) by mouth was studied. Exposure to ethanol occurred at various times during the cycle leading to ovulation and shortly after fertilization. The chromosome constitution of all preimplantation embryos isolated from these females was determined either at the first cleavage mitosis or at the morula stage. The incidence of aneuploidy in the ethanol-exposed groups at these times was approximately 19% and 13.5%, respectively, with a similar number of monosomic and trisomic conceptuses observed at these times. In addition, about 2% of all conceptuses examined were triploid. Further females were autopsied on the 10th or 11th day of gestation, though the chromosome constitution of only the morphologically abnormal or developmentally retarded embryos was determined. Eight embryos out of a total of 16 studied in the ethanol-exposed group were either aneuploid or triploid, whereas in the control group only one out of 11 examined proved to be aneuploid. The triploids and ethanol-induced aneuploid conceptuses appeared to be capable of surviving to the morula stage but generally failed to survive to the 10th/11th day. No monosomics were in fact observed in the postimplantation series. The present findings are briefly discussed with reference to the possible pathogenesis of spontaneous abortions in man, which often possess similar types of chromosomal anomalies.