Optimization of parthenogenetic activation protocol of in vitro matured buffalo oocytes following vitrification.

[Objective]The effect of vitrification and different parthenogenetic activations on the potential development of vitrified-warmed buffalo oocytes was studied to provide references for establishment of a specific activation protocol. [Method]The matured buffalo oocytes were cryopreserved for 1-2 days by vitrification method. Oocytes were treated by parthenogenetic activation after vitrification and thawing, and untreated fresh matured oocytes were used as the control. Following parthenogenetic activation, the effects of ionomycin concentration, concentration and processing time of 6-DMAP on vitrified-warmed oocytes were evaluated. [Result]The cleavage, 4-cell, 8-cell and blastocyst development rates of vitrified-thawed oocytes were all significantly lower than the control group(P<0.01). The vitrified-thawed matured buffalo oocytes were cultured in 6-DMAP at 2 mmol/L for 2 hours after treated with 3.5 μmol/L ionomycin for 5 minutes, and the rates of cleavage, 4-cell, 8-cell and blastocyst were 60.6%, 45.1%, 33.7% and 14.8%, respectively. [Conclusion]The threshold of vitrified-thawed oocytes after activation might have changed, therefore, vitrified matured buffalo oocytes need a specific parthenogenetic activation protocol different from the unverified fresh oocytes. [ABSTRACT FROM AUTHOR]