In Vitro Maturation And Fertilization Capacity Of Mouse GV-Stage Oocyte Following Stepwise Vitrification

摘要

Background: The storage of oocytes is important for advances in reproductive biology and infertility treatment. Although successful procedures for cryopreservation of human metaphase II oocytes have been reported, their results have proven unsatisfactory, and appear to require further progress. The microtubular spindle of MII oocytes is sensitive to temperature changes. Germinal vesicle (GV) stage oocytes do not have microtubular spindle, so its cryopreservation may be an alternative approach to the storage of gametes.Aims: examining the viability and subsequent developmental ability of murine GV oocytes after vitrification.Setting: Embryology research center at an academic institution.Design: Original ArticleMethods and Materials: Germinal vesicle oocytes with cumulus cells were transferred to vitrification solution, which was composed of 30% (v/v) ethylene glycol, 18% (w/v) Ficoll-70, and 0.3 M sucrose either by single step or in a step-wise way. After vitrification and storage in liquid nitrogen, the oocytes were thawed and washed two times in medium TCM199 and then subjected to in vitro maturation, fertilization and culture. Results: The oocyte survival, maturation to MII, fertilization and development rates in step-wise exposure were found to be significantly higher (P<0.05) when compared with corresponding rates in the single step procedure. Collected data was analyzed by one way ANOVA test. Conclusion: The results of present study indicate that GV stage oocytes have better morphology and viability after vitrification in stepwise method; and their rates of maturation and development to 2-cell stage are also higher as compared to oocytes cryopreserved via single step procedure.