Impact of chronic low-dose ethanol ingestion during sexual maturation of female mice on in-vitro and in-vivo embryo developments

Little is known of the consequences of ethanol intake prior to fertilizatio n on preimplantation embryo development. Recently we showed that chronic 10 and 5% w/v ethanol intake by young female mice reduces in vitro fertilizat ion (IVF) rates. The purpose of the present work was to investigate whether the adverse effects of preconceptional low-dose chronic ethanol intake by sexually maturing female mice affects preimplantation embryo growth in vitr o or in vivo in subsequent pregnancy. Prepubertal female mice were given 5% ethanol in their drinking water for 30 days. On day 27 and 29 of the ethan ol treatment, females were superovulated. IVF-derived cultured embryos (in vitro development) or embryos obtained from oviducts and uteri (in vivo dev elopment) were evaluated. Whether analyzed on a per embryo or per dam basis , ethanol treatment was associated with a significant decrease in progressi on through embryo stages during the seven days of in vitro development and with an increase in morphologically abnormal embryos. Progression through e mbryo stages during four days of in vivo development was also inhibited by ethanol pretreatment of dams At 99 h post-hCG of in vivo development, there were fewer total, hatched, and expanded blastocysts, and a complete absenc e of implanting blastocysts among females treated with ethanol. In summary, low-dose chronic ethanol consumption of sexually maturing female mice prio r to conception has adverse effects on preimplantation embryo development, both under in vitro and in vivo conditions, manifested as retarded developm ent, embryo anormalities, and a reduction in expansion and hatching of the preimplantation blastocyst. (C) 2001 Elsevier Science Inc. All rights reser ved.