title: Preimplantation development of in vitro-matured and in vitro-fertilized ovine zygotes: comparison between coculture on oviduct epithelial cell monolayers and culture under low oxygen atmosphere.
abstract: The roles of medium composition, serum source, embryo coculture, and culture under low O2 conditions on the development of in vitro-matured and in vitro-fertilized (IVMF) ovine zygotes were investigated in three separate experiments. In the first experiment, the proportion of cocultured IVMF zygotes developing to the blastocyst stage was significantly higher (38.0% vs. 3.5%; p < 0.05) than that of non-cocultured zygotes treated within three embryo culture media (TCM-199 + 10% fetal bovine serum [FBS]; bicarbonate-buffered, glucose-free synthetic oviduct fluid medium [mod-SOFM] + 10% FBS; and bicarbonate-buffered BSA-free Tyrode's salt solution [mod-TALP] + 10% FBS) under a 5% CO2 atmosphere in air. In a second experiment, a significantly higher (p < 0.05) proportion of cocultured zygotes placed in TCM-199 medium survived to the blastocyst stage (37.4% blastocysts vs. 23.4% in mod-SOFM). No significant effect of serum (FBS vs. human serum [HS]) was observed on embryonic development, but coculture was confirmed to exert a significant influence on development to the blastocyst stage. In the final experiment, survival of the embryo under a reduced oxygen (5% CO2:5% O2:90% N2) atmosphere was investigated. In contrast to results in the initial experiments, embryonic survival was significantly higher (p < 0.05) in the non-cocultured treatment groups (21.9% blastocysts vs. 0.4% for cocultured zygotes). Serum source also had a significant (p < 0.05) influence upon the development of non-cocultured zygotes: 32.3% of zygotes cultured with HS progressed to the blastocyst stage vs. 11.5% of zygotes cultured in FBS-supplemented medium. These results have characterized two distinct culture environments, each capable of supporting the development of high frequencies of unselected IVMF zygotes to the blastocyst stage in vitro.
authors.affiliation: Department of Obstetrics and Gynaecology, University of Western Ontario, London, Canada.
authors.forename: A J
authors.initials: AJ
authors.lastname: Watson
authors.forename: P H
authors.initials: PH
authors.lastname: Watson
authors.forename: D
authors.initials: D
authors.lastname: Warnes
authors.forename: S K
authors.initials: SK
authors.lastname: Walker
authors.forename: D T
authors.initials: DT
authors.lastname: Armstrong
authors.forename: R F
authors.initials: RF
authors.lastname: Seamark
mesh_terms: D000818:Animals; D001639:Bicarbonates; D001755:Blastocyst / Q000502:physiology; D002021:Buffers; D002478:Cells, Cultured; D003470:Culture Media; D047108:Embryonic Development / Q000502:physiology*; D004847:Epithelial Cells; D004848:Epithelium / Q000502:physiology; D005187:Fallopian Tubes / Q000166:cytology / Q000502:physiology*; D005260:Female; D005307:Fertilization in Vitro; D009028:Morula / Q000502:physiology; D010100:Oxygen / Q000008:administration & dosage*; D011247:Pregnancy; D012756:Sheep / Q000196:embryology; D015053:Zygote / Q000254:growth & development*
chemical_list: D001639:Bicarbonates; D002021:Buffers; D003470:Culture Media; D010100:Oxygen