title: Post-thaw viability of in vivo-produced canine blastocysts cryopreserved by slow freezing.
abstract: The objectives were to evaluate the reexpansion blastocoele rate, post-thaw viability, and in vitro development of canine blastocysts cryopreserved by slow freezing in 1.0 m glycerol (GLY) or 1.5 m ethylene glycol (EG). Fifty-one in vivo-produced canine blastocysts were randomly allocated in two groups: GLY (n = 26) and EG (n = 25). After thawing, embryos from M0 were immediately stained with the fluorescent probes propidium iodide and Hoechst 33 342 to evaluate cellular viability. Frozen-thawed embryos from M3 and M6 were cultured in SOFaa medium + 10% FCS at 38.5°C under an atmosphere of 5% CO(2) with maximum humidity, for 3 and 6 days, respectively, and similarly stained. The blastocoele reexpansion rate (24 h after in vitro culture) did not differ between GLY (76.5%) and EG (68.8%). Post-thaw viable cells rate were not significantly different between GLY and EG (66.5 ± 4.8 and 57.3 ± 4.8, respectively, mean ± SEM), or among M0 (62.3 ± 5.7%), M3 (56.9 ± 6.0%), and M6 (66.5 ± 6.0%). In conclusion, canine blastocysts cryopreserved by slow freezing in 1.0 m glycerol or 1.5 m ethylene glycol, had satisfactory blastocoele reexpansion rates, similar post-thawing viability, and remained viable for up to 6 days of in vitro culture.
authors.affiliation: Laboratory of Animal Reproduction, Federal University of Espirito Santo, Brazil, UFES, Department of Veterinary Medicine, Alegre Campus, Alto Universitário, Caixa Postal 16, Alegre, ES, Brazil.
authors.forename: C Renato de Freitas
authors.initials: CR
authors.lastname: Guaitolini
authors.forename: M Onghero
authors.initials: MO
authors.lastname: Taffarel
authors.forename: N Soares
authors.initials: NS
authors.lastname: Teixeira
authors.forename: M José
authors.initials: MJ
authors.lastname: Sudano
authors.forename: P Maria Coletto
authors.initials: PM
authors.lastname: Freitas
authors.forename: M Denise
authors.initials: MD
authors.lastname: Lopes
authors.forename: F da Cruz
authors.initials: Fda C
authors.lastname: Landin-Alvarenga
authors.forename: C Alvarenga
authors.initials: CA
authors.lastname: de Oliveira
authors.forename: M Rezende
authors.initials: MR
authors.lastname: Luz
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000502:physiology*; D015925:Cryopreservation / Q000379:methods / Q000662:veterinary*; D003451:Cryoprotective Agents; D004285:Dogs / Q000196:embryology*; D046149:Embryo Culture Techniques / Q000662:veterinary; D047108:Embryonic Development; D019855:Ethylene Glycol; D005260:Female; D005990:Glycerol; D006358:Hot Temperature; D011247:Pregnancy
chemical_list: D003451:Cryoprotective Agents; D019855:Ethylene Glycol; D005990:Glycerol