Effects of porcine granulocyte-macrophage-colony-stimulating factor on porcine cumulus-oocyte complex maturation in vitro

Introduction: The in vitro maturation (IVM) of oocytes is an essential step in the in vitro embryo production. This study aimed to improve the efficacy of IVM by supplementing with granulocyte-macrophage colony stimulating factor (GM-CSF) in the culture medium. Methods: The combinatorial effects of GM-CSF and porcine follicular fluid (pFF) were also investigated in porcine cumulus-oocyte complex (COC) models. COCs were obtained by aspirating follicles with an 18 G needles. Small and medium follicles were used in this study. COCs from two kinds of follicles were divided into 13 groups to investigate the maturation of COCs at different concentrations of pFF (0,10%) and GM-CSF (0, 2, 10, 20 ng/mL). The maturation of COCs was evaluated by different variables including cumulus expansion, the appearance of the first polar body, lipid droplet localization, mitochondrial distribution, and cortical granule distribution. Results: The results showed that GM-CSF improves the cumulus expansion, and stimulate the mitochondrial and cortical granule movement. However, GM-CSF did not increase nuclear maturation or lipid droplet localization rates in the porcine oocyte. Conclusion: In conclusion, porcine GM-CSF had some positive effects on the porcine oocyte maturation.