Theca cell monolayer co-culture improves oocyte in vitro maturation and subsequent embryo development in buffalo (Bubalus bubalis)

Theca cells (TCs) are essential regulators of both follicular development and regression, as they produce androgens that serve as precursors for granulosa cell aromatization. The present study aimed to examine the effects of TC monolayer co-culture on oocyte in vitro maturation (IVM) and subsequent embryonic development in buffalo. The results showed that TC monolayer co-culture not only promoted IVM efficiency but also enhanced subsequent parthenogenetic activation embryonic development of buffalo oocytes. TC monolayer co-culture improved both the expression levels of estrogen synthesis-related genes ( CYP11A1 , CYP19A1 , and 3β-HSD ) and the secretion levels of estradiol in buffalo cumulus cells (CCs) surrounding in vitro-matured oocytes. Furthermore, TC monolayer co-culture influenced the sensitivity of buffalo CCs surrounding in vitro-matured oocytes to FSH. Besides, TC monolayer co-culture upregulated the expression levels of the main components of cAMP/PKA signaling pathway ( cAMP , PKA , and CREB ). This study indicated that TC monolayer co-culture enhanced buffalo oocyte IVM and subsequent embryonic development by associating with cAMP/PKA signaling pathway, responsiveness of CCs to FSH, and subsequent estrogen synthesis by CCs.