Theca cell-conditioned medium enhances steroidogenesis competence of buffalo (Bubalus bubalis) granulosa cells

Theca cells (TCs) play a crucial role in follicular development and atresia. TCs synthesize androgens that act as substrate for granulosa cells (GCs) aromatization to oestrogens needed for follicular growth. However, the effects of TCs in the form of conditioned medium on steroidogenesis in buffalo GCs remain unclear. In the present study, the impacts of TC-conditioned medium (TCCM) on oestrogen synthesis in buffalo GCs were examined. The results showed that TCs secreted principally testosterone, but almost no androstenedione or oestradiol into TCCM. TCs at passage 3 had a stronger secretion capacity of testosterone in TCCM. Furthermore, TCCM collected at 72 hr improved both the expression levels of oestrogen synthesis-related genes (CYP11A1, CYP19A1, 3β-HSD and 17β-HSD) and the secretion levels of estradiol in GCs. The treatment of 72 hr in TCCM promoted both the expression levels of oestrogen synthesis-related genes (CYP11A1, CYP19A1 and 3β-HSD) and the secretion levels of estradiol in GCs. Besides, TCCM that was collected at 72 hr and applied to GCs for 72 hr (72 & 72 hr) improved the sensitivity of buffalo GCs to FSH. This study indicates that TCCM (72 & 72 hr) enhances the steroidogenesis competence of GCs mainly through facilitating the responsiveness of GCs to FSH in buffalo.