Mangiferin promotes porcine oocyte maturation and delays the postovulatory aging process by up-regulating NRF2 levels

Abstract

Mangiferin (MGN), a flavonoid known for its anti-inflammatory and antioxidant properties, was evaluated in this study for its effects on porcine oocyte maturation in vitro, as well as its potential to modulate the mechanisms associated with aging oocytes. The inclusion of 0.1 μM MGN in the IVM culture medium significantly enhanced blastocyst development following parthenogenetic activation, while also notably upregulating the expression of key embryonic development genes, including SOX2, PCNA, POU5F1, and DNMT3A. MGN treatment improved the oocytes' antioxidant capacity and mitochondrial functionality, concurrently reducing cathepsin B activity and lowering LC3B protein expression (1.06 ± 0.09 vs. 0.55 ± 0.12). To investigate the underlying mechanisms, NRF2 expression was assessed, revealing a marked increase in NRF2 fluorescence and a significant elevation in both NRF2 mRNA and protein levels (1.00 ± 0.05 vs. 1.25 ± 0.09) following MGN treatment compared to the control group. Additionally, MGN treatment enhanced the early developmental potential of aged oocytes, elevating GSH levels and mitochondrial membrane potential and reducing ROS accumulation. Furthermore, MGN treatment upregulated antioxidant genes (SOD1, SOD2). Collectively, these findings suggest that MGN improves porcine oocyte maturation in vitro and enhances subsequent developmental potential through the activation of NRF2 signaling. Moreover, MGN may also delay postovulatory oocyte aging by boosting antioxidant defense and mitochondrial function in aged oocytes.