title: Oocyte maturation, embryo development and gene expression following two different methods of bovine cumulus-oocyte complexes vitrification.
abstract: OBJECTIVE
  To examine the maturational competence, embryo development and expression of genes involved in oocyte maturation and cumulus expansion (GDF9, BMP15, HAS2, TNFAIP6, FGF17 and FSHr) following two standard methods of bovine COCs vitrification.
  
  
  METHODS
  Bovine cumulus-oocyte complexes (COCs) were aspirated from slaughtered ovaries and then distributed into three groups: non-vitrified COCs (control), vitrification 1 group (V1); vitrification was performed by 15% ethylene glycol (EG) and 15% DMSO in holding media (TCM-199 with 20% FCS); and vitrification 2 group (V2); vitrification was performed by 40% EG in holding media. After vitrification, COCs were warmed in two steps and cultured and then evaluated for nuclear maturation, embryo development and gene expressions.
  
  
  RESULTS
  The mean (±SD) percentages of nuclear maturation and blastocyst/cleaved were higher in control group (79.5 ± 8.0 and 31.0 ± 5.1%) than the V1 (34.8 ± 9.1 and 4.4 ± 5.1%) and V2 (47.8 ± 11.7 and 7.1 ± 5.8%) groups (P < 0.05), respectively. Further, COCs in V2 group showed higher mean (±SD) percentages of cleavage compared to V1 group (31.8 ± 1.0 vs 21.7 ± 2.8%; P < 0.05). GDF9 and BMP15 expression levels were higher in COCs in the control than of the vitrification groups (P < 0.05). In addition, expression level of GDF9 and BMP15 was higher in V2 group than in V1group (P < 0.05). The expression of HAS2 and FGF17 in V1 group was lower (P < 0.05) than that of the V2 groups.
  
  
  CONCLUSIONS
  Expression of oocyte maturation genes was affected by vitrification procedure and conditions. Using EG alone for vitrification of bovine immature COCs, resulted in higher expression of GDF9, BMP15 and production of more in vitro matured and cleaved oocytes.
authors.affiliation: Department of Animal Reproduction, School of Veterinary Medicine, Shiraz University, Shiraz, Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Azari
authors.affiliation: Department of Animal Reproduction, School of Veterinary Medicine, Shiraz University, Shiraz, Iran. kafi@shirazu.ac.ir.
authors.forename: Mojtaba
authors.initials: M
authors.lastname: Kafi
authors.affiliation: Department of Embryology, Reproductive Biomedicine Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran.
authors.forename: Bita
authors.initials: B
authors.lastname: Ebrahimi
authors.affiliation: Department of Embryology, Reproductive Biomedicine Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran.
authors.forename: Roya
authors.initials: R
authors.lastname: Fatehi
authors.affiliation: Shiraz Rostami Human Assisted Reproductive Center, Shiraz, Iran.
authors.forename: Mahboobeh
authors.initials: M
authors.lastname: Jamalzadeh
mesh_terms: D000818:Animals; D002417:Cattle; D054885:Cumulus Cells / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D004121:Dimethyl Sulfoxide / Q000494:pharmacology*; D047108:Embryonic Development / Q000187:drug effects*; D019855:Ethylene Glycol / Q000494:pharmacology*; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects*; D058989:Vitrification
chemical_list: D019855:Ethylene Glycol; D004121:Dimethyl Sulfoxide
keywords: Bovine; Embryo development; Gene expression; Vitrification