Introduction: Mouse embryos can successfully be frozen with sucrose and propandiol. However, different developmental stages of mammalian embryos have shown to have various capacities to undergo freeze-thawing procedure. In the present study, the ability of 1,2,4 and 8-ell mouse embryo to tolerate the freeze-thawing procedure was investigated and the effect of this procedure on the further in vitro development.
Materials and Methods: One, 2,4 and 8-cell mouse embryos were flushed from the excised uteri of the gonadotropin treated mice. Morphologically normal embryos were frozen slowly with propandiol and sucrose and thawed rapidly. The survived embryos were cultured for 4-5 days and their development in the later stages such as hatching blastocyst was compared with non-frozen embryos.
Results: The rate of survival for 1-cell embryos was higher than the other stages. The survival rates were 91, 80, 82 and 85% for 1, 2, 4 and 8-cell embryos respectively.The rate of development of the embryos beyond the late blastocyst stage was greater in 4 and 8-cell embryos. In addition to that, the 4-cell embryos developed to hatching blastocyst as it is compared with 2 and 8-cell stages embryo (P0<0.05).
Conclusion: The different development stages of mouse embryos can successfully be frozen. However, the survival rate and post-thawing development is correlated with the developmental stage of the frozen embryos.