Mitoquinone mesylate enhances bovine oocyte in vitro maturation efficiency by modulating oxidative stress and...

This study probed the regulatory role of mitoquinone mesylate (MitoQ) on oxidative stress (OS) and mitochondrial function during the in vitro maturation (IVM) of bovine oocytes. To this end, MitoQ was added to the IVM medium at concentrations of 0, 50, 100, and 150 nmol/L. Compared with untreated controls, supplementation with 50 nmol/L MitoQ significantly improved the first polar body extrusion (PBE) rate, cleavage rate, and blastocyst formation rate (P < 0.05). Biochemical and cellular analyses further revealed that treatment with 50 nmol/L MitoQ led to a marked reduction in apoptotic death and intracellular reactive oxygen species (ROS) content (P < 0.01), accompanied by significant increases in glutathione (GSH) content and adenosine triphosphate (ATP) production (P < 0.05). In addition, mitochondrial membrane potential (MMP) was significantly elevated in the 50 nmol/L MitoQ group compared to controls (P < 0.01). Gene expression analysis indicated that antioxidant-related genes (SOD, SIRT2, SIRT3) and mitochondrial dynamics-associated genes (DNM1, DNM2, MFN2) were significantly upregulated (∗P < 0.05, ∗∗P < 0.01, ∗∗∗P < 0.001). Conversely, the pro-apoptotic gene BAX was significantly downregulated (∗∗P < 0.01), whereas expression of the anti-apoptotic gene BCL-2 was significantly increased (∗P < 0.05). Collectively, these findings demonstrate that supplementation of IVM medium with 50 nmol/L MitoQ effectively alleviates OS-induced injury, enhances mitochondrial energy metabolism, and substantially improves oocyte maturation quality and subsequent embryonic developmental potential.