Dish-microdrop method in the vitrification of mouse embryos

Objective To study the dish microdrop method in the vitrification of KunBai mouse 8～12 cell embryos and test the cryopreservation efficiency. Methods The embryos were first incubated in EG 20 for 3 minutes and then transferred to EFS 40 for 1 minute. An EFS 40 microdrop less than 0.5μl containing mouse embryos was expelled onto a 35 mm dish which was immediately dipped directly into liquid nitrogen. Results After thawing, we got a recovery rate of 98.1% and no zona pellucida damage was observed.Furthermore, the revival rate of the vitrification method was as high as 95.2% after the freezing and thawing cycle.There was no significant difference between the frozen and unfrozen embryos in development ability in vitro and in vivo (84.3% vs 90.1%,12.1% vs 13.5%,P0.05,respectively). Conclusion KunBai mouse 8～12 cell embryos can be vitrified with the dish microdrop method efficiently.