Cryobiological effects of cryoprotectants on morphology of cumulus oocyte complexes (COCs) of sheep oocytes using vitrification

The aim of this study was to investigate the effect of different cryoprotectants like glycerol and DMSO individually and in combination of both on morphology of sheep oocytes using vitrification. The vitrification of sheep oocytes was performed using 40% glycerol and 40% DMSO individually and in combination of 20% glycerol + 20% DMSO. It was found that combination of cryoprotectants proved more efficient than using 40% glycerol or 40% DMSO alone. The morphological damages were less (8% vs 16% vs. 15% respectively) using combination of glycerol than using 40% glycerol and 40% DMSO alone. Glycerol and DMSO when used alone found to induce adverse effect on the morphology of sheep oocytes. However combination of 20% glycerol + 20% DMSO found better to maintain the integrity and internal structure of sheep oocytes by vitrification.