Piperine improves the quality of porcine oocytes by reducing oxidative stress

Oxidative stress caused by light and high temperature arises during in vitro maturation (IVM), resulting in low-quality embryos compared with those obtained in vivo. To overcome this problem, we investigated the influence of piperine (PIP) treatment during maturation of porcine oocytes on subsequent embryo development in vitro. Porcine oocytes were cultured in IVM medium supplemented with 0, 50, 100, 200, or 400 μM PIP. After parthenogenetic activation, the blastocyst (BL) formation was significantly higher and the apoptosis rate was significantly lower using 200 μM PIP-treated oocytes (200 PIP). In the 200 PIP group, the level of reactive oxygen species at the metaphase II stage was decreased, accompanied by an increased level of glutathione and increased expression of antioxidant processes (Nrf2, CAT, HO-1, SOD1, and SOD2). Consistently, chromosome misalignment and aberrant spindle organization were alleviated and phosphorylated p44/42 mitogen-activated protein kinase activity was increased in the 200 PIP group. Expression of development-related (CDX2, NANOG, POU5F1, and SOX2), anti-apoptotic (BCL2L1 and BIRC5), and pro-apoptotic (BAK, FAS, and CASP3) processes was altered in the 200 PIP group. Ultimately, embryo development was improved in the 200 PIP group following somatic cell nuclear transfer. These findings suggest that PIP improves the quality of porcine oocytes by reducing oxidative stress, which inevitably arises via IVM. In-depth mechanistic studies of porcine oocytes will improve the efficiencies of assisted reproductive technologies.