Erythropoietin supplementation during in vitro maturation enhances the developmental competence of porcine oocytes as assessed by parthenogenetic activation.

Porcine oocyte in vitro maturation (IVM) remains suboptimal because current culture systems do not fully recapitulate the follicular environment present in vivo. Erythropoietin (EPO), a cytoprotective factor reported in the ovarian follicular compartment, may contribute to the regulation of oocyte maturation; but its role during porcine IVM remains unclear. This study investigated the presence and localization of EPO in porcine ovarian follicles and evaluated whether EPO supplementation during IVM improves oocyte developmental competence as assessed by parthenogenetic activation. EPO immunoreactivity was detected in porcine oocytes and surrounding follicular cells across multiple follicular stages. Porcine cumulus-oocyte complexes were then cultured in IVM medium supplemented with 0, 10, 100, or 1000 mU/mL EPO for 42 h. Nuclear maturation rates did not differ among groups, whereas 100 mU/mL EPO significantly increased blastocyst formation following parthenogenetic activation. EPO treatment was also associated with increased mitochondrial membrane potential-related fluorescence and MitoTracker fluorescence, reduced intracellular reactive oxygen species levels, increased BCL-2 expression, and reduced CASP3-related apoptotic signals. These findings suggest that EPO supplementation during porcine oocyte IVM enhances PA-assessed developmental competence and is associated with mitochondrial-related changes, reduced oxidative stress, and attenuated apoptosis-associated signals.