Effect of porcine immature oocyte vitrification on oocyte-cumulus cell gap junctional intercellular communication

Vitrification may severely affect cumulus cells and oocyte morphology and viability, limiting their maturation and developmental potential. The aim of this study was to evaluate the gap junction intercellular communication (GJIC) integrity after the vitrification of porcine immature cumulus-oocyte complexes (COCs). Fresh COCs were randomly distributed in three groups: untreated (control), toxicity (cryoprotectants exposure), and vitrification, then subjected to in vitro maturation (IVM). Oocyte viability and IVM were measured in all groups. The evaluation of GJIC was expressed as relative fluorescence intensity (RFI). Vitrification significantly decreased oocyte viability and maturation after 44 h of culture compared to control. Also, significantly reduced RFI was observed in vitrified COCs during the first hours of culture (4-8 h) compared to control. This study demonstrates that porcine oocyte viability and maturation after 44 h of culture decreased after vitrification. GJIC was also affected during the first hours of culture after the vitrification of immature oocytes, being one of the possible mechanisms by which oocyte maturation decreased.