Alteration in localization of steroid hormone receptors and coregulatory proteins in follicles from cows with induced ovarian follicular cysts

SALVETTI NR; ALFARO N; VELAZQUEZ M; AMWEG A; MATILLER, V; DIAZ, PU; ORTEGA HH

REPRODUCTION

BIOSCIENTIFICA LTD

Lugar: Bristol; Año: 2012 vol. 144 p. 723 - 735

1470-1626

Cystic ovarian disease (COD) is an important cause of infertility in cattle. The altered follicular dynamics and cellular differentiationobserved in COD may be mediated through a disruption of the expression of steroid receptors and their associated transcriptionalcofactors. The aim of this study was to determine the protein expression profiles of ESR1, ESR2, PGR, AR, NCOA3, NCOR2, andPHB2 (REA) in ovarian follicles in an experimental model of COD induced by the administration of ACTH. Ovaries were collected andfollicles were dissected from heifers during the follicular phase (control) or from heifers treated with ACTH to induce the formationof ovarian follicular cysts. Ovaries were fixed, sectioned, and stained immunohistochemically for steroid receptors and the associatedtranscription factors. The relative expression of ESR1 was similar in follicular cysts and in tertiary follicles from both control andcystic cows and was significantly higher than in secondary follicles. The expression of ESR2 in the granulosa was higher in cystic follicles.No differences were seen for PGR. The expression of androgen receptor was significantly increased in tertiary follicles with lowerimmunostaining in cysts. The expression of NCOA3 was observed in the granulosa and theca with a significantly increased expressionin the theca interna of cystic follicles. The highest levels of NCOR2 expression in granulosa, theca interna, and theca externa wereobserved in cysts. In granulosa cells, NCOR2 levels increase progressively as follicles mature and the treatment had no effect. In summary,ovaries from animals with induced COD exhibited altered steroid receptor expression compared with normal animals, as well as changesin the expression of their regulators. It is reasonable to suggest that in conditions characterized by altered ovulation and follicularpersistence, such as COD, changes in the intra-ovarian expression of these proteins could play a role in their pathogenesis.