Effects of Pterostilbene on the Activation of Nuclear Factor Erythroid 2-Related Factor 2 Pathway During in vitro Maturation of Mouse Oocytes

Pterostilbene (PTS) is a natural polyphonic compound known to have biological activities, such as antioxidant and anticancer effects. This study was designed to regulate the effect of pterostilbene on the in vitro maturation (IVM) of mouse oocytes denuded of the cumulus (DOs). Different concentration of PTS was added to IVM media with immature DOs. After maturation, meiosis II (MII) stage rates oocytes, Measurement of reactive oxygen species (ROS) and glutathione (GSH) levels, activation of the Nuclear Factor Erythroid 2 like 2 (NFE2L2) pathway and apoptotic expression of BCL2 family in MII oocytes were determined. Our results showed that: PTS significantly increased the MII rate of DOs (P < 0.05). Moreover, PTS decreased the ROS levels in DOs (P < 0.05) and increased the GSH levels (P < 0.05). Furthermore, PTS addition in DOs significantly increased the protein expression of NFE2L2 in the nucleus and decreased Kelch-like ECH-associated protein1 (KEAP1). PTS significantly increased the antioxidant enzyme expression of catalase (CAT), heme oxygenase1 (HMOX1), and superoxide dismutase (SOD). In addition, PTS lowered the protein expression of apoptotic Bcl-2-associated X protein (BAX) and increased the protein expression of anti-apoptotic B-cell lymphoma2 (BCL2) as well as PTS treatment significantly increased the gene expression of BCL2 and reduced the expression of apoptotic BAX in matured DOs. These results indicated that pterostilbene significantly improved the IVM quality matured of DOs and activate NFE2L2-Keap1 pathway during maturation of oocytes.