Altered expression of estrogen receptors α and β in bovine ovarian follicular persistence

NOTARO US; HUBER E; RECCE S; STASSI AF; SALVETTI NR ; REY F ; ORTEGA HH; RODRÍGUEZ FM

Buenos Aires

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

Sociedad Argentina de Investigación Clínica (SAIC) y Sociedades relacionadas

Steroidhormone receptors are members of the superfamily of ligand-regulatedtranscription factors that modulate gene transcription by different mechanismsand as a consequence they are able to activate or repress gene expression. Inmammals, estrogens modulate the growth, differentiation and the femalephysiology through estrogen receptor (ER) α and ERβ. Cystic ovarian disease contributes toreproductive deficiency in lactating dairy cows. The endocrine profile, growthdynamics and histological characteristics of cystic follicles are similar tothose of induced-persistent follicles in a model of subluteal progesteroneadministration. The purpose of the present study was to analyze the expressionof ERα and ERβ by immunohistochemistry (IHC) inovarian follicular structures during the development of follicular persistenceinduced in cows by long time progesterone administration. A low dose ofprogesterone was administered (n=5) for 0 (ovulation time, P0) and 5 (P5), 10(P10), and 15 (P15) days after the expected day of ovulation using anintravaginal progesterone-releasing device. Control cows (group C) received noadditional hormonal treatment. After IHC technique, digital image analysis wasperformed on ovary slides to quantify the immunostaining in preovulatoryfollicles of the control group as reference structure and persistent folliclesof P0, P5, P10 and P15 groups. ERα expression was higher in preovulatory follicles of the control groupthan in the persistent follicles of the P5, P10 and P15 groups, in bothgranulosa and theca interna cells (p <0.05). Expression of ERβ was similar in the categoriesanalyzed, both in granulosa and theca interna cells (p> 0.05). These resultssuggest that changes in the expression of estrogen receptors, mainly ERα, can lead to an altered response ofsteroid hormones, and thus contribute to the pathogenesis of ovarianalterations such as follicular persistence and cystic ovarian disease.