Effect of Melatonin and Epigallocatechin-3-Gallate Combination on In Vitro Maturation of Mouse Oocytes

In vitro oocyte maturation (IVM) is a pivotal process influencing the success of embryo production in laboratory and clinical settings. However, oxidative stress (OS) often compromises oocyte quality during IVM. Antioxidants such as melatonin and epigallocatechin-3-gallate (EGCG) are known to mitigate OS by neutralizing reactive oxygen species (ROS) and bolstering antioxidant defenses. Despite extensive studies on their individual effects, the synergistic impact of melatonin and EGCG remains underexplored. Utilizing a mouse model, this study evaluated their combined effect on oocyte maturation, focusing on nuclear and cytoplasmic development, intracellular ROS, glutathione (GSH) levels, and subsequent embryonic competence. The results demonstrated that melatonin and EGCG significantly enhanced the polar body extrusion rate (p < 0.05), with the combination group achieving the highest rate of 91.96%. Cumulus expansion was observed to improve across all treated groups, with the combination treatment showing the highest cumulus expansion index (CEI) of 3.06. Furthermore, the combination treatment significantly reduced ROS levels and increased GSH content, indicating enhanced antioxidant capacity (p < 0.01). Embryonic development outcomes, including cleavage and blastocyst rates, were markedly higher in the combination group at 75.23% and 53.97%, respectively, demonstrating superior developmental potential (p < 0.01). These findings suggest that the melatonin–EGCG combination offers a novel and effective strategy to combat oxidative damage during IVM, thereby improving oocyte quality and embryonic development potential in mice.