Vitrification of immature goat oocytes by solid surface vitrification technique

Abstract

The immature oocytes were vitrified by solid surface vitrification (SSV) technique. Oocytes were instantly vitrified with minimum quantity (1-2 J.lI) droplets of vitrification medium into a solid metallic surface, partially immersed into liquid nitrogen (LN2).The recovered rate ofnormal oocytes after thawing, cumulus expansion and polar body observed in vitrified-thawed with cumulus (VTe) were significantly higher as compared to vitrified-thawed oocytes without cumulus (VTO). The rate ofrecovered normal oocytes after thawing were 40.23±2.56% and 22.66±1.84% in VTC and VTa group respectively. Similarly polar body observed in VTC and VTO groups were 32.18±2.88% and 15.33±3.05% respectively. However, the cumulus expansion in non-vitrified with cumulus (NVC) group was significantly higher than VTC group (58.73±4.79% vs 32. 18±:2.88%). In line with the values with the cumulus expansion, the polar body development was also significantly high in NVC group as compared to VTC group (57.14±4.64% vs 32.18±4.43%). The high rate of cryosurvival following vitrification by SSV method used in the present study may be due to high . cooling rate, using the combination of microdrops and improved heat exchange achieved by direct contact with metal surface. The technique after further standardization can provide a steady source ofmaterials for in-vitro embryo production and embryo manipulation research.