title: Effects of hyaluronic acid in culture and cytochalasin B treatment before freezing on survival of cryopreserved bovine embryos produced in vitro.
abstract: One limitation to the widespread use of in vitro-produced embryos in cattle is their poor survival following cryopreservation. Two approaches for enhancing survival of in vitro-produced bovine embryos following cryopreservation were evaluated: culture in the presence of hyaluronic acid and alterations in the cytoskeleton through cytochalasin B treatment. The experiment was a 2 x 2 factorial design to test main effects of hyaluronic acid added to culture at day 5 after insemination (+ or -) and cryopreservation treatment (control or cytochalasin B). Embryos used for cryopreservation were blastocysts and expanded blastocysts harvested on day 7 after insemination. Cytochalasin B increased the percent of embryos that re-expanded (P < 0.0001) and that hatched following thawing (P < 0.05). The hatching percent was 29.6% for embryos treated with cytochalasin B versus 9.1% for control embryos. There was no significant effect of hyaluronic acid on survival although there was a tendency for embryos cultured with hyaluronic acid to have higher percent hatching if not treated with cytochalasin B (12.7% for hyaluronic acid versus 4.5% for control; hyaluronic acid x cytochalasin B interaction; P = 0.09). In conclusion, cytochalasin B treatment before freezing improved cryosurvival of bovine embryos produced in vitro. Such a treatment could be incorporated into methods for cryopreservation of bovine embryos provided post-transfer survival is adequate. In contrast, culture with hyaluronic acid was of minimal benefit- the increased cryosurvival in the absence of cytochalasin B was not sufficient to allow an adequate number of embryos to survive.
authors.affiliation: Department of Animal Sciences, University of Florida, Gainesville Florida 32611-0910, USA.
authors.forename: M
authors.initials: M
authors.lastname: Franco
authors.forename: P J
authors.initials: PJ
authors.lastname: Hansen
mesh_terms: D000818:Animals; D002417:Cattle; D002470:Cell Survival / Q000187:drug effects*; D015925:Cryopreservation / Q000379:methods*; D003571:Cytochalasin B / Q000494:pharmacology*; D004622:Embryo, Mammalian / Q000187:drug effects / Q000502:physiology*; D047108:Embryonic Development / Q000187:drug effects; D006820:Hyaluronic Acid / Q000494:pharmacology*; D046509:Tissue Culture Techniques
chemical_list: D003571:Cytochalasin B; D006820:Hyaluronic Acid