Analysis of the ovarian estrogen receptor Α and β in cows gestated under heat stress conditions

NOTARO, U; HUBER E; RECCE, S; DIAZ, PU; ORTEGA HH; REY, F; SALVETTI, NATALIA R.; RODRIGUEZ, F.M.

Mar del Plata

Congreso; LXIII Reunión Científica Anual de la Sociedad Argentina de Investigación Clínica (SAIC); 2018

Sociedad Argentina de Investigación Clínica

Theeffects of adverse ambient conditions (number of days with temperature-humidityindex (THI) exceeding the comfort threshold: >72) on dairy cows can affect thereproduction not only in a direct way, also in the progeny of the animals thatwere gestated under stress conditions. In fact, the ovarian follicular reserveis established during the first half of the fetal life (0-150 days) and many factorscan affect the future fertility of the offspring. Within these factors, EstrogenReceptors (ER) α and β are the most important regulators which gene expressioncould be modulated. The aim of this study was to evaluate the gene and protein expressionof ERα and ERβ in preovulatory follicles of animals gestated under heat stressin different stages of pregnancy. Holstein cows (n=20) were divided in twogroups: group 1 (cows gestated under heat stress between 0-150 days ofpregnancy) and group 2 (cows gestated under heat stress between 151days-end ofpregnancy). Similar levels of ERα and β mRNA were detected by real time PCR, infollicular wall of different groups analyzed (p>0.05). For quantitativemethylation analysis of the 5´UTR sequences of ERα and β, an AGENA?s MassARRAYplatform was used. No differences were detected for any CpG analyzed for bothreceptors (p>0.05). On the other hand, the protein expression evaluated byimmunohistochemistry show similar levels of ERα in granulosa and theca internaof preovulatory follicles of the groups analyzed (p>0,05) and a higherexpression of ERβ in granulosa and theca cells of preovulatory follicles of cowsof Group 2 related to Group 1 (p<0.05). These data suggest that changes inthe expression of estrogen receptors, mainly ERβ, can lead to an alteredresponse of steroid hormones, and thus contribute to ovarian alterations in animalsgestated under heat stress.