Comparison of Survival Rate, Presence and Location of Meiotic Spindle after Vitrification of Mouse Oocytes between Open and Close Systems

The present study aims to compare the survival rate, reconstitution and dislocation of meiotic spindle of mouse oocyte vitrification between open and close systems.

131 matured oocytes (containing meiotic spindle) harvested from 6-8 week-old BALB/C and divided into two groups of open and close systems. After exposure of oocytes in vitrification media, oocytes were loaded on cryotop in open group and on Rapid-i in close group, and then vitrified. After warming, oocytes were incubated for 3 hours and evaluated for survival rate, presence and location of re-polymerized meiotic spindle by PolScope system.

Survival rate was significantly higher in open system compared to close system (91.1% vs 68.6%, respectively). 81.3% and 51.2% of survived oocyte contained meiotic spindle in close and open system, respectively (p<0.05). The percentage of nature location of meiotic spindle was more in close system, significantly.

Survival rate in open system is more than close system, but close system can preserve meiotic spindle and nature location better than open system. Also, it seems that the evaluation of meiotic spindle is essential for vitrified oocytes by PolScope system.