title: Cryopreservation of blastomeres separated from two-cell mouse embryos by an ultrarapid freezing method.
abstract: OBJECTIVE
  To clarify the developmental capacity of frozen two-cell blastomeres, we investigated in vivo and in vitro viabilities of blastomeres that were frozen ultrarapidly after separation from two-cell mouse embryos. Two-cell embryos obtained from superovulated F1 hybrid females were denuded by treatment with 0.5% pronase solution and then induced to separate into two single blastomeres by gentle pipetting. The blastomeres were cryopreserved by an ultrarapid freezing method.
  
  
  RESULTS
  The preimplantation developmental rate of two-cell embryos frozen in 3.0 M DMSO was significantly higher than the rate of those frozen in 15 and 4.5 M DMSO (at least P < 0.05). The in vitro developmental rate of the ultrarapidly frozen-thawed blastomeres separated from two-cell embryos (75.0%) was similar to that of nonfrozen blastomeres (76.0%). When eight pairs of blastocysts that developed from frozen two-cell mouse blastomeres were transferred to pregnant ICR recipients on Day 3, four live singletons were born.
  
  
  CONCLUSIONS
  Thus, the results indicate that two-cell mouse blastomeres can be frozen by the ultrarapid freezing method.
authors.affiliation: Genetic Engineering Research Institute, KIST, Taejon, Korea.
authors.forename: M J
authors.initials: MJ
authors.lastname: Kang
authors.forename: Y M
authors.initials: YM
authors.lastname: Han
authors.forename: C S
authors.initials: CS
authors.lastname: Lee
authors.forename: S T
authors.initials: ST
authors.lastname: Shin
authors.forename: K K
authors.initials: KK
authors.lastname: Lee
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000502:physiology; D001757:Blastomeres / Q000737:chemistry*; D015925:Cryopreservation / Q000379:methods*; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D004624:Embryo Transfer; D004622:Embryo, Mammalian / Q000737:chemistry* / Q000166:cytology* / Q000187:drug effects; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008813:Mice, Inbred ICR; D011247:Pregnancy; D011256:Pregnancy Outcome
chemical_list: D004121:Dimethyl Sulfoxide