Ghandy N, Karimpur Malekshah AA. Which Stage of Mouse Embryos Is More Appropriate for Vitrification?
INTERNATIONAL JOURNAL OF FERTILITY & STERILITY 2017;
10:357-362. [PMID:
28042416 PMCID:
PMC5134751 DOI:
10.22074/ijfs.2016.5086]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 07/16/2016] [Indexed: 11/22/2022]
Abstract
Background
Vitrification has been shown as one of the most effective methods of
cryopreservation for mammalian embryos. However, there is no consensus which stage
of embryonic development is the most appropriate for vitrification with subsequent
maximal development after thawing. This study was carried out to explore and compare
the effect(s) of vitrification on mouse 2-cell, 4-cell, 8-cell, morula and blastocyst
stage embryos and subsequent blast formation and hatching after thawing.
Materials and Methods
In this experimental study, 2-cell embryos were obtained from
the oviducts of super ovulated female NMRI mice. Some embryos were randomly selected
and vitrified through a two-step media protocol and cryotop. Other embryos were cultured
to assess their development. During the ensuing days, some of these cultured embryos were
vitrified at 4-cell, 8-cell, morula and blastocyst stages. After 10 to 14 days, the embryos
were thawed to assess their survival and also cultured to determine the rate of blastocyst
formation and hatching. The results were analyzed using one-way ANOVA and Tukey’s
post-hoc tests.
Results
There was no significant difference in the survival rates of vitrified embryos
at 2-cell, 4-cell, 8-cell, morula and blastocyst stages after thawing (P>0.05). The blastocyst
formation rate of vitrified 8-cell embryos was significantly higher than that of
2-cell embryos (P<0.05). The hatching rate of vitrified 4-cell, 8-cell and blastocysts
were significantly higher than that of 2-cell embryos (P<0.05).
Conclusion
Vitrification is suitable for cryopreservation of all stages of mouse embryonic
development. However, the best tolerance for vitrification was observed at 4and 8-cell
stages of development. Accordingly, the development of vitrified embryos to blastocysts,
following thawing, was most efficacious for 4 and 8-cell embryos. Compared to mouse
2-cell embryos, embryos vitrified as blastocysts had the highest rate of hatching.
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