Eugenol enhances the in vitro maturation of dromedary camel oocytes

During in vitro embryo production, oxidative stress can compromise oocyte competence and subsequent embryo development. Phenolic antioxidants derived from plants, including eugenol (EG), represent a promising strategy to reduce the detrimental effects of reactive oxygen species (ROS) accumulation and improve embryo development outcome. This study investigated the concentration-dependent effects of EG on the in vitro maturation (IVM) of dromedary camel cumulus-oocyte complexes (COCs). COCs were cultured in IVM medium containing 0 (control), 10, 20, 40, and 80 μM EG. Supplementation with 10 or 20 μM EG significantly increased oocyte maturation rates compared with control, whereas supplementation with 40 or 80 μM EG provided no additional benefit. Immunofluorescence analysis showed that all EG-treated groups exhibited a significant increase in lipid content and mitochondrial activity. However, the effect was significantly greater at 10 and 20 μM. Assessment of the spent IVM media showed that superoxide dismutase (SOD) and catalase (CAT) levels were significantly increased at 20 μM EG, while malondialdehyde (MDA) levels were reduced at 10 and 20 μM relative to the control. Additionally, cumulus cells recovered from oocytes matured with 10 and 20 μM EG displayed increased transcript levels of BCL2, CAT, IGF1, and SOD1 genes. Collectively, these findings indicate that EG at 10 and 20 μM may enhance IVM of camel oocytes by promoting nuclear maturation, cumulus expansion, mitochondrial activity, and lipid accumulation, accompanied by increased transcript levels of BCL2, CAT, IGF1, and SOD1.