title: Gene expression, oocyte nuclear maturation and developmental competence of bovine oocytes and embryos produced after in vivo and in vitro heat shock.
abstract: Three assays were performed. In assay 1, oocytes harvested during the winter months were subjected to kinetic heat shock by stressing the oocytes at 39.5°C (HS1) or at 40.5°C (HS2) for either 6, 12, 18 or 24 h and then matured at control temperature (38.5°C). The nuclear maturation rates (NMR) of all oocytes were recorded after 24 h. In assay 2, oocytes collected year-round maturated, were implanted via in vitro fertilization (IVF) and developed for 9 days. Gene expression analysis was performed on target genes (Cx43, CDH1, DNMT1, HSPA14) with reference to the two housekeeping genes (GAPDH and SDHA) in embryos. Similarly, in assay 3, genetic analysis was performed on the embryos produced from heat-stressed oocytes (from HS1 and HS2). In assay 1, the duration of heat stress resulted in a significant decline in NMR (P < 0.05) with HS1 for maturated oocytes at 86.4 ± 4.3; 65.5 ± 0.7; 51.3 ± 0.9; 38.1 ± 1.9 and 36.3 ± 0.9, for control, 6 h, 12 h, 18 h and 24 h, respectively. For assays 2 and 3, results demonstrated that DNMT1, Cx43 and HSPA14 were down-regulated in the embryos produced in the warm with respect to the cold months (P < 0.05). A constant up- and down-regulation of DNMT1 and HSPA14 genes were observed in both HS-treated samples. Also, an inconsistent pattern of gene expression was observed in Cx43 and CDH1 genes (P < 0.05). Targeted gene expression was aberrant in embryo development, which can provide evidence on early embryo arrest and slowed embryo development.
authors.affiliation: Department of Agrarian Sciences,CITA-A (Research Centre for Agricultural and Environmental Sciences and Technology of the Azores),Animal Reproduction,University of the Azores,Angra do Heroísmo 9700-042,Portugal.
authors.forename: Krishna C
authors.initials: KC
authors.lastname: Pavani
authors.affiliation: Centro Universitário Monte Serrat,Rua Comendador Martins,52 - Vila Matias,Santos - SP,11015-530,Brazil.
authors.forename: Erica
authors.initials: E
authors.lastname: Baron
authors.affiliation: Department of Agrarian Sciences,CITA-A (Research Centre for Agricultural and Environmental Sciences and Technology of the Azores),Animal Reproduction,University of the Azores,Angra do Heroísmo 9700-042,Portugal.
authors.forename: Pedro
authors.initials: P
authors.lastname: Correia
authors.affiliation: Department of Agrarian Sciences,CITA-A (Research Centre for Agricultural and Environmental Sciences and Technology of the Azores),Animal Reproduction,University of the Azores,Angra do Heroísmo 9700-042,Portugal.
authors.forename: Joana
authors.initials: J
authors.lastname: Lourenço
authors.affiliation: Instituto de Investigação e Inovação em Saúde,Institute for Molecular and Cell Biology (IBMC),University of Porto,Porto,Portugal.
authors.forename: Bruno Filipe
authors.initials: BF
authors.lastname: Bettencourt
authors.affiliation: Department of Agrarian Sciences,CITA-A (Research Centre for Agricultural and Environmental Sciences and Technology of the Azores),Animal Reproduction,University of the Azores,Angra do Heroísmo 9700-042,Portugal.
authors.forename: Madalena
authors.initials: M
authors.lastname: Sousa
authors.affiliation: Departamento de Ciências Agrárias,Secção Reprodução,Campus de Angra do Heroísmo,Universidade dos Açores,Rua Capitão João D'Avila,9700-042 Angra do Heroísmo,Portugal.
authors.forename: Fernando Moreira
authors.initials: FM
authors.lastname: da Silva
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000502:physiology*; D015820:Cadherins / Q000235:genetics; D002417:Cattle; D018031:Connexin 43 / Q000235:genetics; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000235:genetics; D005260:Female; D005307:Fertilization in Vitro; D018507:Gene Expression Regulation, Developmental; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics; D018869:Heat-Shock Response / Q000502:physiology*; D059471:In Vitro Oocyte Maturation Techniques / Q000379:methods*; D008297:Male; D009028:Morula / Q000502:physiology; D009865:Oocytes / Q000502:physiology*; D012621:Seasons
chemical_list: D015820:Cadherins; D018031:Connexin 43; D018840:HSP70 Heat-Shock Proteins; D004248:DNA (Cytosine-5-)-Methyltransferases
keywords: Apoptosis; Gene quantification; Kinetic heat shock; Maternal heat stress; Nuclear maturation