Cryopreservation of strains and mutant genes in mice.
Three kinds of freezing methods were tested with embryos of DNI strain. The survival rate after thawing was 47.5%, 66.7% and 77.8% in the 2-step method, modified slow freezing method and modified 2-step method, respectively. Then, the modified 2-step method was applied to the embryos from 7 strains and a pair of interstrain crosses. PMSG treatment at the beginning of diestrus following HCG treatment after 48 hrs resulted in much yield of 8-16-cell embryos in all strains. The average number for each strain was as follows: DNI; 18.9, DDN; 13.0, BS; 20.4, C57BL/6; 12.9, DBA/2; 17.5, CRN; 19.8, PAN; 13.7 and DNI x C57BL/6-Ay; 21.7. Development of frozen-thawed embryos in culture varied among strains. Proportion of embryos that developed to the morula or blastocyst stage was as follows: DNI; 64.6%, DDN; 71.9%, BS; 53.6%, C57BL/6; 57.3%, DBA/2; 65.0%, CRN; 52.5%, PAN; 17.4% and DNI x C57BL/6-Ay; 44.1%. These results indicate that the ability of embryos to survive freezing and thawing is influenced by their genetic background. Live young were produced from DNI, DDN, BS and DNI x C57BL/6-Ay embryos after transfer to recipients. Comparative assessment of the developmental ability of frozen-thawed embryos after transfer among strains should be performed in further study.
Yoshiki
A
A
Laboratory of animal genetics, School of Agriculture, Nagoya University, Japan.
Ohno
K
K
Wakasugi
N
N
D000818:Animals; D004624:Embryo Transfer; D004622:Embryo, Mammalian; D005260:Female; D005615:Freezing; D005838:Genotype; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains / Q000235:genetics*; D008817:Mice, Mutant Strains / Q000235:genetics*; D011309:Preservation, Biological