Altered expression of Bcl-2 and Bax in follicles within dehydroepiandrosterone-induced polycystic ovaries in rats.

BAS DIANA; ABRAMOVICH DALHIA; HERNANDEZ FATIMA; TESONE MARTA

CELL BIOLOGY INTERNATIONAL

ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD

Año: 2011 vol. 35 p. 423 - 429

1065-6995

PCOS (polycystic ovary syndrome) is a heterogeneous disease characterized by hyperandrogenaemia, hirsutism, oligo- oramenorrhea, insulin resistance and anovulation. The aim of the present study was to evaluate if the balance between theovarian expression of Bax (proapoptotic protein) and Bcl-2 (antiapoptotic protein) is altered in a PCOS model developedin rats by DHEA (dehydroepiandrosterone) administration. In addition, the ovarian morphology and the circulating progesteronelevels were evaluated. Histological studies confirmed the presence of follicular cysts, atretic follicles and theabsence of corpora lutea in the ovaries from the PCOS group and a significant decrease in circulating progesterone levels.Immunohistochemical studies showed that the expression of Bcl-2 and Bax were mainly localized in granulosa cells of AFs(antral follicles) in both groups. Bax expression was greater in preantral and AFs from PCOS ovarian sections than in thecontrols. In contrast, intense Bcl-2 immunostaining was observed in the control AFs, while Bcl-2 protein was either absent inPFs (preantral follicles) or weakly expressed in AFs from PCOS rats. These results were partially confirmed by westernstudies. Data revealed that the ovarian level of Bcl-2 protein was lower in PCOS than in the control and that there wereno differences in Bax ovarian levels between groups. However, Bax/Bcl-2 ratio was significantly higher in PCOS group thanin the control group. In conclusion, an increase in ovarian apoptosis through an imbalance among the Bcl-2 familymembers may be involved in the transformation of growing follicles in cystic follicles in the ovaries from DHEA-inducedPCOS rats.