title: Immature bovine oocyte cryopreservation: comparison of different associations with ethylene glycol, glycerol and dimethylsulfoxide.
abstract: Research on different cryoprotectants and their associations is important for successful vitrification, since greater cryoprotectant concentration of vitrification solution may be toxic to oocytes. The aim of the present research was to compare the efficiency of immature bovine oocyte vitrification in different associations of ethylene glycol (EG), glycerol and dimethylsulfoxide (Me(2)SO). In the first experiment, oocytes were exposed to the cryoprotectant for either 30 or 60s in final solutions of EG+DMSO1 (20% EG+20% Me(2)SO) or EG+DMSO2 (25% EG+25% Me(2)SO) or EG+GLY (25% EG+25% glycerol). In the second experiment, the oocytes were vitrified in open pulled straws (OPS) using 30s exposure of final solutions of EG+DMSO1 or EG+DMSO2 or EG+GLY. Maturation rates of 30s exposure groups were not different from the control, but 60s cryoprotectant exposure was toxic, decreasing maturation rates. The vitrification with EG+DMSO2 resulted in enhanced maturation rate (29.2%) as compared with EG+DMSO1 (11.7%) and EG+GLY (4.3%) treatments. These data demonstrate that concentration and type of cryoprotectant have important effects on the developmental competence of vitrified oocytes.
authors.affiliation: São Paulo University, Faculty of Veterinary Medicine, São Paulo, São Paulo, Brazil.
authors.forename: Claudia
authors.initials: C
authors.lastname: Yamada
authors.forename: Heloísa Vasconcellos Amaral
authors.initials: HV
authors.lastname: Caetano
authors.forename: Renata
authors.initials: R
authors.lastname: Simões
authors.forename: Alessandra Corallo
authors.initials: AC
authors.lastname: Nicacio
authors.forename: Weber Beringui
authors.initials: WB
authors.lastname: Feitosa
authors.forename: Mayra Elena Ortiz D'Avila
authors.initials: ME
authors.lastname: Assumpção
authors.forename: José Antônio
authors.initials: JA
authors.lastname: Visintin
mesh_terms: D000818:Animals; D002417:Cattle / Q000502:physiology*; D015925:Cryopreservation / Q000379:methods / Q000662:veterinary*; D003451:Cryoprotective Agents / Q000737:chemistry / Q000494:pharmacology*; D004121:Dimethyl Sulfoxide / Q000737:chemistry / Q000494:pharmacology; D019855:Ethylene Glycol / Q000737:chemistry / Q000494:pharmacology; D005260:Female; D005990:Glycerol / Q000737:chemistry / Q000494:pharmacology; D009865:Oocytes / Q000166:cytology / Q000187:drug effects* / Q000502:physiology
chemical_list: D003451:Cryoprotective Agents; D019855:Ethylene Glycol; D005990:Glycerol; D004121:Dimethyl Sulfoxide