Korean J Reprod Med.  2007 Jun;34(2):117-124.

Comparison of Vitrification and Slow Freezing for the Cryopreservation of Mouse Pronuclear Stage Embryos

• Kim MY
• Lee YI

Abstract

OBJECTIVE
The aim of this study was to compare the efficacy of slow freezing with vitrification method for cryopreservation of mouse pronuclear stage embryos.
METHODS
Mouse pronuclear embryos obtained from superovulated mice and classified into 2 groups of slow freezing and vitrification. Slow freezing solution consisted of 1.5 M PROH, 0.1 M sucrose, while vitrification solution consisted of 40% ethylene glycol, 18% Ficoll and 0.5 M sucrose diluted in Dulbecco's phosphate-buffered saline supplemented with 10% SSS. Recovery and survival rates after thawing and development rates to hatching balstocyst stage were compared between two groups. RESULT: After freezing and thawing, recovery rate of slow freezing group was 93.8%, whereas vitrification group was 66.5% (p<0.01). Survival rate of recovered embryos were similar between two groups as 83.2% in slow freezing and 87.6% in vitrification. Embryo development rates to 2-cell stage after 24 hrs (77.0% vs 59.1%), 4-cell after 48 hrs (72.6% vs 53.3%), blastocyst after 96 hrs (53.1% vs 40.1%) of thawing were significantly higher in vitrification group than those of slow freezing group, respectively.
CONCLUSION
The vitrification method may provide better developmental competence of frozen-thawed embryos than that of slow freezing method for cryopreservation of mouse pronuclear stage embryos.

Keyword

Mouse pronuclear embryo; Vitrification; Slow freezing; Embryo development; Blastocyst

MeSH Terms

Animals
Blastocyst
Cryopreservation*
Embryonic Development
Embryonic Structures*
Ethylene Glycol
Female
Ficoll
Freezing*
Mental Competency
Mice*
Pregnancy
Sucrose
Survival Rate
Vitrification*
Ethylene Glycol
Ficoll
Sucrose