PERINATAL EXPOSURE TO ETHINYLESTRADIOL IMPAIRS PREGNANCY DEVELOPMENT IN MICE

MEYER N; ZENCLUSSEN AC; SANTAMARÍA, CG; MULLER JE; ABUD, J.E.; RODRÍGUEZ HORACIO ADOLFO

MAR DEL PLATA

Congreso; LXIII Reunión Científica Anual de la Sociedad Argentina de Investigación Clínica (SAIC), Reunión Anual de la Sociedad Argentina de Fisiología (SAFIS), LXVI Reunión Anual de la Soc. Argentina de Inmunología; 2018

SAIC

Ethinylestradiol (EE) is a potent synthetic estrogen used principallyin the female oral contraceptive pill. Due to its widespread use,EE has been detected in river systems around the world. Here westudied how EE exposure around implantation affects pregnancy,particularly concentrating on placentation and uterine remodeling.C57BL/6 pregnant female mice were exposed to 5 μg EE/kg/day,0.005 μg EE/kg/day or 0.1% ethanol by oral gavage from day 1 to7 of gestation. The number of implantation sites and the abortionrate in each group was determined at gd 5, 10 and 14 respectively.Weight of fetuses and placentas was recorded and the fetal developmentwas assessed by high frequency ultrasound. Blood velocityin the arteria uterina was analyzed by Doppler measurements. Theremodeling of uterine spiral arteries (SA) was studied in HE-stainedslides of transversal sections of implantations. We showed thatshort-term exposure to EE around implantation has negative conseconsequences:the remodeling of SA was impaired in low dose EE-treatedmothers as well as a significant higher fetal and placental weight,whereas fetuses of high doses EE-treated mothers die intrauterine.Our work revealed unsuspected short-term effects of EE on pregnancyand urges to more studies dissecting the mechanisms behindthe negative actions of EE during early pregnancy.