[Cryopreservation of mouse morula and blastocysts by vitrification].

Objective: To compare the survival and developmental potential of mouse morula, early blastocysts and blastocysts cryopreserved by vitrification.

Methods: One hundred and forty-two mouse morula, 135 early blastocysts and 148 blastocysts were cryopreserved by 6 mol/L ethylene glycol and 1 mol/L sucrose vitrification solutions. The survival rates and blastocysts hatching rates after thawing were observed.

Results: The survival rates of morula, early blastocysts and blastocysts groups were 88.0%, 73.3%, and 60.1% respectively. The blastocyst hatching rates were 73.9%, 61.5%, and 49.3% respectively. Both the survival rates and blastocyst hatching rates in morula group were higher than those in early blastocysts group (P < 0.05), and they were higher in early blastocysts group than in blastocysts group (P < 0.05).

Conclusions: In these three embryo stages, the survival and developmental potential of mouse morula cryopreserved by vitrification are better than those of early blastocysts and blastocysts. Morula is likely the most feasible stage for embryo vitrification.