Korean J Fertil Steril.  2000 Jun;27(2):191-200.

Effects of the Stepwise Exposure Treatments Before Freezing on the Survival Capacity of the Frozen-Thawed Mouse Mature Oocytes by Vitrification or Ultra-Rapid Freezing

• Kim SW
• Lee YA
• Yoon MS
• Lee KS
• Lee JI
• Kim MK

Abstract

OBJECTIVE
This study was carried out to compare the effects of the stepwise exposure treatments on the morphological normality, fertilization and blastocyst formation rate of the frozen-thawed mouse mature oocytes by vitrification or ultra-rapid freezing and to use as a fundamental data for the cryopreservation of human oocytes.
MATERIALS AND METHODS
The morphological normality and fertilization rates of the vitrified and ultra-rapid frozen mouse mature oocytes after three-stepwise exposure treatments (1step, 3step and 5step) were observed. After choosing the 3step exposure treatment groups, we observed the morphological normality and fertilization, blastocyst formation rate vitrified and ultra-rapid frozen mouse mature oocytes.
RESULTS
The morphological normality and fertilization rates of the vitrified mouse mature oocytes after three-stepwise exposure treatments (1step, 3step and 5step) were 75%, 85%, 88% and 58%, 61%, 54% respectively. There were no significant differences among treatments (p>0.05). The morphological normality and fertilization rates of the control was 92% and 65%. There were no significant differences in fertilization rate among control and treatments (p>0.05). The morphological normality and fertilization rates of the ultra-rapid frozen mouse mature oocytes after three-stepwise exposure treatments (1step, 3step and 5step) were 83%, 83%, 84% and 75%, 63%, 56% respectively. There were no significant differences among treatments (p>0.05). The morphological normality and fertilization rate of the control was 95% and 67%. There were no significant differences among control and treatments (p>0.05). The morphological normality and fertilization rate of the vitrified or ultra-rapid frozen mouse mature oocytes after 3step exposure treatment were 69% and 75%, respectively. The blastocyst formation rate was 60% and 57%. The results did not differ significantly between vitrification and ultra-rapid freezing (p>0.05).
CONCLUSION
As known in the above results, there were no significant differences in the fertilization and blastocyst formation rate of the frozen-thawed mouse mature oocytes by vitrification or ultra-rapid freezing among the control and treatments. It is suggested that vitrification and ultra-rapid freezing method were effective for the cryopreservation of mouse mature oocytes.

MeSH Terms

Animals
Blastocyst
Cryopreservation
Fertilization
Freezing*
Humans
Mice*
Oocytes*
Vitrification*