Cryopreservation of mouse zona-free embryos and embryos exposed to biopsy and reconstruction by vitrification in microdrops.
Zona-free zygotes, 2-cell, 4-cell, and 8-cell embryos, morulae, blastocysts and embryos exposed to biopsy and reconstruction were cryopreserved in microdrops of vitrification medium expelled directly into liquid nitrogen. While none of the zygotes and 2-cell embryos survived storage in liquid nitrogen, 54% 4-cell and 97% 8-cell embryos, 99% morulae, 88% blastocysts, 98% biopsied and 100% reconstructed embryos were intact one hour after thawing. Developmental potential of cryopreserved zona-free embryos evaluated after 30 h of in vitro culture was high. Of the frozen embryos, 49% 4-cell and 92% 8-cell embryos, 95% morulae, 79% blastocysts, 84% biopsied and 90% reconstructed embryos were capable of further cleavage. After the transfer of zona-free 8-cell embryos, morulae, blastocysts, biopsied and reconstructed embryos into day-1 recipients - 4 (16%), 14 (56%), 3 (12%), 0 and 8 (32%) live foetuses were recorded, respectively.
Landa
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Koltzov Institute of Developmental Biology of the Academy of Sciences of the USSR, Moscow.
D000818:Animals; D015925:Cryopreservation / Q000379:methods*; D004622:Embryo, Mammalian; D005775:Gastrula; D051379:Mice; D008815:Mice, Inbred Strains / Q000196:embryology*; D009028:Morula; D015044:Zona Pellucida; D015053:Zygote