Expression of adiponectin and its receptors (AdipoR1 and AdipoR2) in goat ovary and its effect on oocyte nuclear maturation in vitro

Adiponectin is an adipokine secreted primarily by adipocytes and is involved in the control of male and female reproductive functions. Circulating levels of adiponectin are inversely correlated with body fat mass, and its biological effects are predominantly mediated through two receptors, AdipoR1 and AdipoR2. The aim of the present study was to verify the expression of the adiponectin system (adiponectin and its receptors, AdipoR1 and AdipoR2) in goat ovary using qPCR and immunohistochemistry analyses and further investigate the in vitro effects of recombinant adiponectin (5 μg/mL and 10 μg/mL) on goat oocyte nuclear maturation. We demonstrated that the mRNA and proteins of the adiponectin system are present in goat ovary. Gene and protein expression of AdipoR1 and AdipoR2 was detected in follicular cells (oocyte, cumulus, granulosa and theca) of small and large antral follicles, while adiponectin mRNA was not detected in oocytes from small and large follicles or in large follicle cumulus cells. Finally, addition of various concentrations of adiponectin in maturation medium affected the number of oocytes that reached metaphase II. In conclusion, in the present study, we detected expression of adiponectin and its receptors AdipoR1 and AdipoR2 in goat ovarian follicles. Furthermore, we demonstrated that recombinant adiponectin increases nuclear maturation of goat oocytes in vitro.