Construction of aggregation chimaeras from 8-cell mouse embryos stored for several years in liquid nitrogen.
Eight-cell embryos of 7 different inbred strains frozen and stored for 2 to 4 years in liquid nitrogen were used as the source of embryos and individual 1/8-blastomeres for construction of different types of aggregation chimaeras. Overall survival of stored embryos, evaluated by in vitro culture, ranged from 63% in A/By to 85% in C57BL/10By embryos. Chimaeric embryos prepared by aggregation of frozen/thawed zona-free 8-cell embryos continued in normal development through expanding blastocysts (77% to 93%) to in vitro implantations. Construction of directed chimaeras by total rebuilding of 8-cell embryos previously stored in liquid nitrogen was successful and resulted in normal development. Of the aggregates made by regular mixing of 1/8-blastomeres obtained from BALB/c and C57BL/6J embryos thawed from liquid nitrogen, 90% reached the blastocyst stage and 77% implanted after 48 h and 96 h of in vitro culture, respectively. Addition of 1/8 blastomeres from frozen/thawed BALB/c embryos to four 1/8-like blastomeres from nuclear transplantation experiments documented, as all of the 30 constructed aggregates formed expanding blastocysts within 48 h of in vitro culture, the possibility of using embryos from embryo banks for the rescue of products of genetic manipulations at the embryo level.
Landa
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V
Institute of Molecular Genetics, Czechoslovak Academy of Sciences, Praha.
Teplá
O
O
D000818:Animals; D001755:Blastocyst / Q000166:cytology*; D002449:Cell Aggregation; D002678:Chimera / Q000502:physiology*; D015925:Cryopreservation; D066298:In Vitro Techniques; D051379:Mice; D008815:Mice, Inbred Strains; D009584:Nitrogen; D053652:Nuclear Transfer Techniques; D013997:Time Factors
D009584:Nitrogen