Experimental study of preventive effect of estradiol on A/J mouse cleft lip using a whole embryo culture system

Abstract

I studied the effect of estradiol on prevention of cleft lip in A/J mice using whole embryo culture system. Embryos of the 10.5th day of gestation (plug day=0) were harvested from untreated pregnant mice, pregnant mice injected subcutaneously with 25μg/kg of estradiol or the solvent of hormone on the 9. 5th day of gestation. As a control of untreated A/J mouse embryos, C 57 BL/6 mouse embryos of same developmental stage were used. These embryos were cultured for 48 hours in pure rat serum containing 2mg/ml of glucose and antibiotics with continuous supply of 95% 0₂ and 5% CO₂ mixture gas by a rotating culture system at 25 to 10 rpm. Both A/J and C 57 BL/6 mouse embryos showed manifest growth and development in vitro. The incidence of cleft lip in vivo in A/J and C 57 BL/6 mice at the 18th day of gestation is 6.2% and 0% respectively. No cleft lip was observed in cultured C 57 BL/6 mouse embryos. Cleft lip was observed in 51.2% of untreated and 52.2% of solvent treated A/J mouse embryos in vitro. By contrast, in estradiol treated group, the incidence of cleft lip was decreased significantly to 21.3% (p<0.001). These results indicate that the effects of estradiol treatment act to the embryos before primary palate formation, and that the genetical predisposition of cleft lip in A/J mouse embryos become resistant to cleft lip.