ALTERED EXPRESSION OF ESTROGEN RECEPTORS α AND β IN BOVINE OVARIAN FOLLICULAR PERSISTENCE.

NOTARO, U.; HUBER, E.; RECCE, S.; STASSI, A.F.; SALVETTI, N.R.; REY, F.; ORTEGA, H.H.; RODRÍGUEZ, F. M.

Congreso; SAIC SAFE SAI; 2017

Steroid hormone receptors are members of the superfamily of ligand-regulated transcription factors that modulate gene transcription by different mechanisms and as a consequence they are ableto activate or repress gene expression. In mammals, estrogensmodulate the growth, differentiation and the female physiologythrough estrogen receptor (ER) α and ERβ. Cystic ovarian diseasecontributes to reproductive defciency in lactating dairy cows. Theendocrine profle, growth dynamics and histological characteristicsof cystic follicles are similar to those of induced-persistent folliclesin a model of subluteal progesterone administration. The purpose ofthe present study was to analyze the expression of ERα and ERβ byimmunohistochemistry (IHC) in ovarian follicular structures duringthe development of follicular persistence induced in cows by longtime progesterone administration. A low dose of progesterone wasadministered (n=5) for 0 (ovulation time, P0) and 5 (P5), 10 (P10),and 15 (P15) days after the expected day of ovulation using an intravaginal progesterone-releasing device. Control cows (group C) received no additional hormonal treatment. After IHC technique, digitalimage analysis was performed on ovary slides to quantify the immunostaining in preovulatory follicles of the control group as referencestructure and persistent follicles of P0, P5, P10 and P15 groups.ERα expression was higher in preovulatory follicles of the controlgroup than in the persistent follicles of the P5, P10 and P15 groups,in both granulosa and theca interna cells (p <0.05). Expression ofERβ was similar in the categories analyzed, both in granulosa andtheca interna cells (p> 0.05). These results suggest that changes inthe expression of estrogen receptors, mainly ERα, can lead to analtered response of steroid hormones, and thus contribute to the pathogenesis of ovarian alterations such as follicular persistence andcystic ovarian disease.