Curcumin Suppresses ROS Production and Increases Mitochondrial Activity in Cumulus Cells and Oocytes of COCs Derived From Non-Vascularized Follicles in Pigs

In vitro maturation (IVM) produces offspring from domestic animals; however, the blastocyst rate after IVM was low. We previously reported that the developmental competence of oocytes derived from follicles with blood vessels absent on the surface (non-vascularized follicles: NVF) is quite low compared to those derived from follicles with blood vessels present on the surface (vascularized follicles: VF). Thus, it is important to develop technique to improve the quality of NVF-derived oocyte by IVM. Since it has been reported that reactive oxygen species (ROS) reduces oocyte quality, in this study, we investigated whether curcumin that is known as antioxidant could improve oocyte quality derived from NVF. As results, cultivation of NVF Cumulus-oocyte complexes (COCs) with curcumin significantly improved cumulus expansion and oocyte meiotic maturation of NVF COCs compared to those of NVF COCs without curcumin. Cultivation with curcumin of NVF COCs significantly improved the proliferative activity of cumulus cells. Furthermore, the cultivation significantly reduced ROS activity and increased mitochondrial activity. Hence, it was revealed that the addition of curcumin to the maturation medium increased mitochondrial activity and reduced ROS levels in NVF-derived cumulus cells and oocytes, thereby improving the maturation of oocytes within COCs.