title: Liquid nitrogen vapour freezing of mouse embryos.
abstract: Mouse morulae were frozen rapidly to -196 degrees C in the presence of glycerol by a two-step procedure; the embryos were transferred directly from -7 degrees C after seeding into liquid nitrogen vapour at -170 to -180 degrees C and then into liquid nitrogen 10-15 min later. Suitable conditions for the survival of embryos frozen with liquid nitrogen vapour were found to be: 2 M-glycerol, 2 M-propylene glycol, 2 M-ethylene glycol; 5-30 min equilibration time at 0 degrees C; 3-60 min holding time in liquid nitrogen vapour; dilution of glycerol with sucrose out of the frozen-thawed embryos; morula and early blastocyst stage embryos. Relatively high survival rates (69-74%) were obtained after rapid freezing by liquid nitrogen vapour. Morulae frozen in this fashion, cultured and transferred to recipients developed into normal young.
mesh_terms: D000818:Animals; D004624:Embryo Transfer; D004622:Embryo, Mammalian; D005615:Freezing; D051379:Mice; D008813:Mice, Inbred ICR; D009584:Nitrogen; D014021:Tissue Preservation / Q000379:methods*; D014022:Tissue Survival
chemical_list: D009584:Nitrogen