Morphological and Hormonal Identiifcation of Porcine Atretic Follicles and Relationship Analysis of Hormone Receptor Levels During Granulosa Cell Apoptosis In vivo

• Published in: 农业科学学报（英文版） 2014 (5), p.1058-1064
• Main Authors: YU De-bing, YU Min-li, LIN Fei, JIANG Bao-chun, YANG Li-na, WANG Si-yu, ZHAO Ying, WNAG Zheng-chao
• Format: Article
• Language: English
• ISSN: 2095-3119
• DOI: 10.1016/S2095-3119(13)60448-7

Recent reports have demonstrated that follicular atresia is initiated or caused by granulosa cell apoptosis followed by theca cell degeneration in mammalian ovaries, but the mechanism of follicular atresia is still to be elucidated. Therefore, our present study was designed to examine our hypothesis that the changes of follicular microenvironment induce the granulosa cell apoptosis during pocrine follicular atresia in vivo. We ifrstly isolated intact porcine antral follicles and identiifed them into three groups, healthy follicles (HF), early atretic follicles (EAF) and progressed atretic follicles (PAF) through morphology and histology. To further conifrm their status, we detected hormone levels in follicular lfuids and the expression level of apoptosis gene Bax in granulosa cells. The rate of progesterone (P) and estradiol (E2) was increased with the expression of Bax, indicating hormone can be used as a marker of granulosa cell apoptosis or follicular atresia. Finally, we analyzed the expression level of hormone receptor genes in granulosa cells and their relationship with follicular atresia. In PAF, the expression of Progesterone receptor (PGR) was increased signiifcantly while estradiol receptor (ER) had no notable changes, which suggesting the increased-PGR accelerated the effect of P-stimulated granulosa cell apoptosis. The dramatic increasing of androgen receptor (AR) expression in PAF and the obvious increase of tumor necrosis factor-αreceptor (TNFR) in EAF indicated that there are different pathways regulating granulosa cell apoptosis during follicular atresia. Together, our results suggested that different pathways of granulosa cell apoptosis was induced by changing the follicular microenvironment during follicular atresia.