title: Effects of two combinations of cryoprotectants on the in vitro developmental capacity of vitrified immature porcine oocytes.
abstract: This study evaluated two cryoprotectant (CPA) combinations, ethylene glycol (EG) + DMSO and EG + propylene glycol (PG), used for the vitrification of germinal vesicle (GV) porcine oocytes. In experiment 1, the equilibration of GV with the two CPA combinations increased (P < 0.05) the percentage of oocytes that degenerated after IVM (18.1 ± 2.3% and 19.4 ± 2.6% for EG + DMSO and EG + PG groups, respectively) compared with control oocytes (7.6 ± 1.3%). However, CPAs did not affect the fertilization or developmental parameters of the embryos. In experiment 2, the percentages of live vitrified-warmed GV oocytes at 2 hours after warming (EG + DMSO: 67.0 ± 2.3% and EG + PG: 57.6 ± 2.3%) were lower than those of fresh control GV oocytes (97.3 ± 0.7%). The percentage of degenerated oocytes after IVM was higher (P < 0.001) in vitrified-warmed oocytes (EG + DMSO: 59.8 ± 2.3% and EG + PG: 56.2 ± 2.6%) than in the control (1.6 ± 1.3). Fertilization efficiency was higher (P < 0.05) in the EG + PG (39.6 ± 2.4%) and control (42.0 ± 2.2%) groups than in the EG + DMSO (26.3 ± 7.7%) group. The cleavage and blastocyst formation rates of the EG + DMSO (25.9 ± 3.5% and 6.6 ± 2.5%, respectively) and EG + PG (20.2 ± 5.4% and 4.7 ± 1.6%, respectively) vitrification groups were lower (P < 0.001) than those observed in the control oocytes (53.4 ± 2.7% and 31.9 ± 1.7%, respectively). In conclusion, in the absence of vitrification, the toxic effects of both CPA combinations on the GV oocytes were minimal. Vitrification resulted in important losses in viability at each step of the in vitro embryo production procedure. However, the surviving oocytes were able to mature and be fertilized, although the fertilization efficiency in the EG + DMSO group was lower. Blastocysts formation was similar for both CPA combinations.
authors.affiliation: Department of Animal Medicine and Surgery, University of Murcia, Murcia, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Nohalez
authors.affiliation: Department of Animal Medicine and Surgery, University of Murcia, Murcia, Spain.
authors.forename: C A
authors.initials: CA
authors.lastname: Martinez
authors.affiliation: Department of Animal Medicine and Surgery, University of Murcia, Murcia, Spain.
authors.forename: M A
authors.initials: MA
authors.lastname: Gil
authors.affiliation: Department of Animal Medicine and Surgery, University of Murcia, Murcia, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Almiñana
authors.affiliation: Department of Animal Medicine and Surgery, University of Murcia, Murcia, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Roca
authors.affiliation: Department of Animal Medicine and Surgery, University of Murcia, Murcia, Spain.
authors.forename: E A
authors.initials: EA
authors.lastname: Martinez
authors.affiliation: Department of Animal Medicine and Surgery, University of Murcia, Murcia, Spain. Electronic address: ccuello@um.es.
authors.forename: C
authors.initials: C
authors.lastname: Cuello
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000166:cytology / Q000502:physiology; D015925:Cryopreservation / Q000662:veterinary; D003451:Cryoprotective Agents / Q000494:pharmacology; D004121:Dimethyl Sulfoxide / Q000008:administration & dosage / Q000494:pharmacology*; D046149:Embryo Culture Techniques / Q000662:veterinary; D047108:Embryonic Development / Q000187:drug effects / Q000502:physiology; D019855:Ethylene Glycol / Q000008:administration & dosage / Q000494:pharmacology*; D009865:Oocytes / Q000187:drug effects / Q000502:physiology; D011092:Polyethylene Glycols / Q000008:administration & dosage / Q000494:pharmacology*; D013552:Swine / Q000196:embryology*; D058989:Vitrification / Q000187:drug effects*
chemical_list: D003451:Cryoprotective Agents; D011092:Polyethylene Glycols; D019855:Ethylene Glycol; D004121:Dimethyl Sulfoxide
keywords: Cryoprotectant; Immature oocyte; Porcine; Vitrification