Pterostilbene alleviates hydrogen peroxide-induced oxidative stress via nuclear factor erythroid 2 like 2 pathway in mouse preimplantation embryos

Pterostilbene (PTS) in blueberries is a phytoalexin with antioxidant properties. PTS exerts strong cytoprotective effects on various cells via Nuclear Factor Erythroid 2 like 2 (NFE2L2) pathway. We evaluated the antioxidant PTS treatment in mouse preimplantation embryos. In vitro culture media were supplemented with different concentrations of PTS. Treatment of zygotes with 0.25 μM PTS improved the development of day 4 blastocysts (P < 0.05). Moreover, H₂O₂ treatment significantly increased the reactive oxygen species level and reduced the glutathione level in mouse blastocyst, whereas PTS treatment counteracted these effects. The fluorescence intensity of apoptotic positive cell was higher in the H₂O₂ group than in the PTS group. Furthermore, PTS-treated embryos significantly increased the protein expression of NFE2L2 in the nucleus and decreased Kelch-like ECH-associated protein1 (KEAP1). PTS treatment significantly increased the expression of downstream target genes involved in the NFE2L2 pathway, such as catalase (CAT), heme oxygenase1 (HMOX1), glutathione peroxidase (GPX), and superoxide dismutase (SOD); these genes confer cellular protection. In addition, PTS treatment significantly increased the expression of anti-apoptotic B-cell lymphoma 2 (BCL2), with a concomitant reduction in the apoptotic Bcl-2-associated X protein (BAX) and Caspase-3 genes in the embryo. PTS treatment also increased the protein expression of BCL2 and reduced the protein expression of BAX in the mouse embryo. In conclusion, PTS activated NFE2L2 signaling pathway in the development of mouse embryos by altering downstream expression of genes involved in the antioxidant mechanisms and apoptosis.