Changes in Ras and Ras-Associated GTPases During Maturation of Porcine Cumulus Cells and Oocytes

Porcine cumulus-oocyte complexes (COCs) undergo dynamic morphological and molecular changes during maturation; however, cell type- and stage-dependent transcript patterns of Ras-related factors in cumulus cells and oocytes remain unclear. This study investigated changes in Ras-related factors during porcine in vitro maturation (IVM). Porcine COCs were cultured under IVM conditions supplemented with follicle-stimulating hormone (FSH), human chorionic gonadotropin (hCG), and epidermal growth factor (EGF). Cumulus cells and oocytes were collected at 0, 22, and 44 h of IVM, and cumulus expansion was monitored using time-lapse imaging. Hormone receptor-related factors, CX43, Ras family members, and their RasGAP and RasGEF regulators were analyzed using RT-PCR and qPCR with band-intensity analysis. Progressive cumulus expansion was observed during IVM. In cumulus cells, R-Ras transcript abundance increased at 22 and 44 h, whereas RASA1 transcript abundance was lower at 44 h. In oocytes, R-Ras and H-Ras transcript abundance decreased during maturation. These findings indicate that selected Ras family members and their regulators exhibit distinct cell type- and stage-dependent transcript patterns during porcine COC maturation. These transcript-level findings provide a basis for future protein-level and functional analyses.