title: Establishment of pregnancies after serial dilution or direct transfer by vitrified equine embryos.
abstract: Experiments were conducted to determine viability of equine embryos in vivo after vitrification. In a preliminary study (Experiment 1), embryos were exposed in three steps to vitrification solutions containing increasing concentrations of ethylene glycol and glycerol (EG/G); the final vitrification solution was 3.4 M glycerol + 4.6 M ethylene glycol in a base medium of phosphate-buffered saline. Embryos were warmed in a two-step dilution and transferred into uteri of recipients. No pregnancies were observed after transfer of blastocysts >300 microm (n = 3). Transfer of morulae or blastocysts < or = 300 microm resulted in four embryonic vesicles (4/6, 67%). In a second experiment, embryo recovery per ovulation was similar for collections on Day 6(28/36, 78%) versus Days 7 and 8(30/48, 62%). Embryos < or = 300 and >300 microm were vitrified, thawed and transferred as in Experiment 1. Some embryos < or = 300 microm were also transferred using a direct-transfer procedure (DT). Embryo development rates to Day 16 were not different for embryos < or = 300 microm that were treated as in Experiment 1(10/22, 46%) or transferred by DT (16/26, 62%). Embryos > 300 microm (n = 19) did not produce embryonic vesicles.
authors.affiliation: Animal Reproduction and Biotechnology Laboratory, Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA.
authors.forename: W D
authors.initials: WD
authors.lastname: Eldridge-Panuska
authors.forename: V Caracciolo
authors.initials: VC
authors.lastname: di Brienza
authors.forename: G E
authors.initials: GE
authors.lastname: Seidel
authors.forename: E L
authors.initials: EL
authors.lastname: Squires
authors.forename: E M
authors.initials: EM
authors.lastname: Carnevale
mesh_terms: D000818:Animals; D001755:Blastocyst; D006063:Chorionic Gonadotropin / Q000008:administration & dosage; D015925:Cryopreservation / Q000379:methods / Q000662:veterinary*; D004624:Embryo Transfer / Q000662:veterinary*; D004622:Embryo, Mammalian / Q000502:physiology; D047108:Embryonic Development; D019855:Ethylene Glycol; D005260:Female; D005990:Glycerol; D006736:Horses; D007315:Insemination, Artificial / Q000662:veterinary; D009028:Morula; D010060:Ovulation; D010062:Ovulation Induction / Q000662:veterinary; D011247:Pregnancy; D012996:Solutions; D020858:Tissue and Organ Harvesting / Q000662:veterinary
chemical_list: D006063:Chorionic Gonadotropin; D012996:Solutions; D019855:Ethylene Glycol; D005990:Glycerol