title: Assessment of ultrarapid and slow freezing procedures for 1-cell and 4-cell mouse embryos.
abstract: Three cryopreservation procedures were assessed for the freezing of mouse 1-cell and 4-cell embryos: the slow freezing protocols with dimethylsulphoxide (DMSO, A) and propanediol (PROH, B) and the ultrarapid procedure with DMSO (C), which was described by the Monash University group [A. Trounson et al. (1987) Fertil. Steril., 48, 843-850]. The evaluation of the different procedures included survival after freezing and thawing, further development after in-vitro culture to blastocysts and the ability to implant and to form living fetuses after transfer of early blastocysts to pseudopregnant mice. In-vitro development was lower in all frozen embryos than in the unfrozen controls. Procedures A and B induced comparable results and were significantly better than ultrarapid freezing. When unfrozen blastocysts were transferred to pseudopregnant mice, 64% of them implanted in the uterine wall and 59% developed to living fetuses. For zygotes the percentages of implantation sites and living fetuses were 47 and 33% for A, 52 and 44% for B, and 29 and 17% for C, respectively. When 4-cell embryos were cryopreserved, these results were 54 and 46% for A, 60 and 53% for B and 37 and 23% for C, respectively. In the ultrarapid procedure we also looked at the influence of the freezing solution. To set up a control, mouse zygotes and 4-cell embryos were exposed to DMSO as in the ultrarapid procedure except that they were not frozen; the survival and blastocyst formation was not different from controls, but fewer living fetuses were born (31% for zygotes and 41% for 4-cell embryos versus 67% in the controls).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Centre for Reproductive Medicine, University Hospital, Dutch-speaking Brussels Free University (Vrije Universiteit Brussel), Belgium.
authors.forename: J
authors.initials: J
authors.lastname: Liu
authors.forename: E
authors.initials: E
authors.lastname: Van den Abbeel
authors.forename: A C
authors.initials: AC
authors.lastname: Van Steirteghem
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D015925:Cryopreservation; D003451:Cryoprotective Agents; D046508:Culture Techniques; D004121:Dimethyl Sulfoxide; D051379:Mice; D019946:Propylene Glycol; D011409:Propylene Glycols; D013997:Time Factors; D015053:Zygote / Q000187:drug effects*
chemical_list: D003451:Cryoprotective Agents; D011409:Propylene Glycols; D019946:Propylene Glycol; D004121:Dimethyl Sulfoxide