LUIZ SERGIO DE ALMEIDA CAMARGO, CNPGLFERNANDA QUEIROS COSTA, UNIVERSIDADE ESTADUAL DO NORTE FLUMINENSE DARCY RIBEIROMICHELE MUNK, UNIVERSIDADE FEDERAL DE JUIZ DE FORASABINE WOHLRES-VIANA, UNIVERSIDADE FEDERAL DE JUIZ DE FORARAQUEL VARELA SERAPIÃO, PESAGROBRUNO CAMPOS DE CARVALHO, CNPGLPAULO HENRIQUE CAMPOS JÚNIOR, UFSJALEX CABRAL VIEIRA, UFVLUIZ ALTAMIRO GARCIA NOGUEIRA, UFFJOAO HENRIQUE MOREIRA VIANA, CENARGEN.2026-07-07http://hdl.handle.net/123456789/442994This study investigated the influence of heat shock during in vitro maturation on embryo development following in vitro fertilization (IVF) or parthenogenesis (Part). Immature bovine cumulus?oocyte complexes were exposed to heat shock (41.0°C) during the first 12 hr of in vitro maturation (IVM), followed by 12 hr at 38.5°C. Control group consisted of in vitro maturation for 24 hr at 38.5°C. Oocytes were in vitro‐fertilized or activated with ionomycin and cultured in vitro for 192 hr post‐in vitro insemination or parthenogenetic activation (hpia). There was an interaction (p < .01) between temperature of IVM and method of oocyte activation (IVF or Part) for cleav‐age at 48 hpia. Heat shock had a negative impact (p < .01) on cleavage of IVF embryos, whereas no (p > .05) effect was found in the Part embryos. Embryo development towards blastocyst stage at 168 and 192 hpia decreased in both IVF and Part embryos derived from heat‐shocked oocytes. Heat shock increased (p < .05) the apoptotic index in Part blastocysts, but no effect (p > .05) was found in IVF counterparts. Heat shock also down‐regulated the expression of AQP3 (p < .01) and up‐regulated the expression of HSP70.1 (p < .01) in Part blastocysts, whereas it down‐regulated the expression of ATP1A1 (p < .05) in IVF blastocysts. In conclusion, the effects of heat shock during IVM on early embryo cleavage and blastocyst apoptosis are influenced by the method of oocyte activation and expression of some genes can be disturbed in embryos derived from heat‐shocked oocytes.openAccessActivationEmbryosMaturationAquaporin 3Hsp70 ProteinIonomycinHeat ShockCleavageBlastocystIn vitro fertilizationParthenogenesisApoptosisGene expressionGametocytesOocytesContrasting effects of heat shock during in vitro maturation on development of in vitro-fertilized and parthenogenetic bovine embryos.Artigo de periódico