title: Effects of gaseous atmosphere and antioxidants on the development and cryotolerance of bovine embryos at different periods of in vitro culture.
abstract: This study examined the effects of antioxidant supplementation and O2 tension on embryo development, cryotolerance and intracellular reactive oxygen species (ROS) levels. The antioxidant supplementation consisted of 0.6 mM cysteine (CYST); 0.6 mM cysteine + 100 μM cysteamine (C+C); 100 IU catalase (CAT) or 100 μM β-mercaptoethanol (β-ME) for 3 or 7 days of in vitro culture (IVC). Two O2 tensions (20% O2 [5% CO2 in air] or 7% O2, 5% CO2 and 88% N2 [gaseous mixture]) were examined. After 7 days of antioxidant supplementation, the blastocyst frequencies were adversely affected (P < 0.05) by CYST (11.2%) and C+C (1.44%), as well as by low O2 tension (17.2% and 11.11% for 20% and 7% O2, respectively) compared with the control (26.6%). The blastocyst re-expansion rates were not affected (P > 0.05) by the treatments (range, 66-100%). After 3 days of antioxidant supplementation, the blastocyst frequencies were not affected (P > 0.05) by any of the antioxidants (range, 43.6-48.5%), but they were reduced by low O2 tension (P < 0.05) (52.1% and 38.4% for 20% and 7% O2, respectively). The intracellular ROS levels, demonstrated as arbitrary fluorescence units, were not affected (P > 0.05) by antioxidant treatment (range, 0.78 to 0.95) or by O2 tension (0.86 and 0.88 for 20% and 7% O2, respectively). The re-expansion rates were not affected (P > 0.05) by any of the treatments (range, 63.6-93.3%). In conclusion, intracellular antioxidant supplementation and low O2 tension throughout the entire IVC period were deleterious to embryo development. However, antioxidant supplementation up to day 3 of IVC did not affect the blastocyst frequencies or intracellular ROS levels.
authors.affiliation: School of Veterinary Medicine,Laboratory of Reproductive Physiology,UNESP-Universidade Estadual Paulista,Araçatuba,SP 16050-680,Brazil.
authors.forename: Nathália Alves de Souza
authors.initials: NA
authors.lastname: Rocha-Frigoni
authors.affiliation: School of Veterinary Medicine,Laboratory of Reproductive Physiology,UNESP-Universidade Estadual Paulista,Araçatuba,SP 16050-680,Brazil.
authors.forename: Beatriz Caetano da Silva
authors.initials: BC
authors.lastname: Leão
authors.affiliation: Brazilian Agricultural Research Corporation,EMBRAPA Pantanal,Corumbá,MS 79320-900,Brazil.
authors.forename: Ériklis
authors.initials: É
authors.lastname: Nogueira
authors.affiliation: School of Veterinary Medicine,Laboratory of Reproductive Physiology,UNESP-Universidade Estadual Paulista,Araçatuba,SP 16050-680,Brazil.
authors.forename: Mônica Ferreira
authors.initials: MF
authors.lastname: Accorsi
authors.affiliation: School of Veterinary Medicine,Department of Animal Health,UNESP-Universidade Estadual Paulista,Araçatuba 16050-680,São Paulo,Brazil.
authors.forename: Gisele Zoccal
authors.initials: GZ
authors.lastname: Mingoti
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001755:Blastocyst / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D002245:Carbon Dioxide / Q000494:pharmacology; D002374:Catalase / Q000494:pharmacology; D002417:Cattle; D015925:Cryopreservation; D003470:Culture Media / Q000494:pharmacology; D003543:Cysteamine / Q000494:pharmacology; D003545:Cysteine / Q000494:pharmacology; D046149:Embryo Culture Techniques / Q000379:methods*; D005260:Female; D008297:Male; D008623:Mercaptoethanol / Q000494:pharmacology; D009584:Nitrogen / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism; D058989:Vitrification
chemical_list: D000975:Antioxidants; D003470:Culture Media; D017382:Reactive Oxygen Species; D002245:Carbon Dioxide; D003543:Cysteamine; D008623:Mercaptoethanol; D002374:Catalase; D003545:Cysteine; D009584:Nitrogen
keywords: Gaseous atmosphere