title: Effect of culture system on survival rate of vitrified bovine embryos produced in vitro.
abstract: This study was designed to evaluate the effect of in vitro culture system on bovine blastocyst yield and quality after vitrification. In Experiment 1, IVM/IVF zygotes were allocated to three culture conditions: (I) Oviductal cells-SOF (OCM-SOF); (II) Oviductal cells-TCM (OCM-TCM); and (III) SOF for 8 days. There was no significant difference between blastocyst rates among groups. In Experiment 2, the IVP-blastocysts in three above culture conditions were vitrified within groups segregated according to age (Day 7 and 8) and blastocoelic cavity size (early and expanded blastocysts). A trend of higher survival rate was obtained in vitrified/warmed early blastocysts compared with expanded ones, so that the difference in OCM-TCM group was significant (P<0.001). Higher survival and hatching rates (P<0.001) were obtained in OCM-SOF and OCM-TCM groups (co-culture) compared with SOF group and the age of blastocyst had no effect on post-thaw survival and hatching rates. In Experiment 3, after staining of blastocysts, in fresh blastocysts the highest number of trophectoderm cells was observed in OCM-TCM group and the number of inner cell mass (ICM) was higher in co-culture groups than SOF group (P<0.001). In vitrified/warmed blastocysts the number of ICM and trophectoderm cells in co-culture groups was higher than SOF group (P<0.001) except for the ICM of expanded blastocysts. In conclusion, in our culture conditions, the blastocyst yield is not influenced by culture system, while the cryotolerance of IVP-blastocysts is positively influenced by the presence of somatic cells. Moreover, the expanded blastocysts are more susceptible to cryoinjury than early blastocysts.
authors.affiliation: Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Sask., Canada S7N 5B4. abs890@mail.usask.ca
authors.forename: A
authors.initials: A
authors.lastname: Shirazi
authors.forename: H
authors.initials: H
authors.lastname: Nazari
authors.forename: E
authors.initials: E
authors.lastname: Ahmadi
authors.forename: B
authors.initials: B
authors.lastname: Heidari
authors.forename: N
authors.initials: N
authors.lastname: Shams-Esfandabadi
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000166:cytology*; D002417:Cattle; D002470:Cell Survival; D018920:Coculture Techniques; D015925:Cryopreservation / Q000662:veterinary*; D046149:Embryo Culture Techniques / Q000662:veterinary*; D047108:Embryonic Development; D005260:Female; D005307:Fertilization in Vitro / Q000662:veterinary*