Efeitos do fator de crescimento dos fibrobalstos 8 (FGF8) durante a maturação in vitro do complexo cumulus-oócito bovino

• Ano de defesa: 2013
• Autor(a) principal: Ormond, Cinthia Marenza [UNESP]
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual Paulista (Unesp)
• Palavras-chave em Português: Bovino - Reprodução; Fertilização in vitro; Fibroblasto; Cattle Reproduction
• Link de acesso: http://hdl.handle.net/11449/108445

Fibroblast growth factor 8 (FGF8) is expressed by the bovine oocyte, activate receptors expressed by cumulus cells and oocytes, and is involved in the regulation of glycolysis and meiosis in the murine COC. The first aim of this study was to assess the effects of FGF8 on cumulus expansion, meiosis progression and energy metabolism in bovine COCs submitted to IVM. Then, once influences on meiosis progression and energy metabolism were observed, effects of FGF8 on abundance of mRNA encoding genes that control these processes were assessed. FGF8 did not affect cumulus expansion but decreased the percentage of oocytes reaching metaphase II, while increasing the percentage of oocytes in metaphase I. This was associated with an inhibitory effect of FGF8 on levels of mRNA encoding Cyclin B1 in the oocyte. In contrast with previous findings in mice, FGF8 decreased mRNA levels of NPR2 in cumulus cells. FGF8 tended to decrease glucose uptake and lactate production, which was accompanied by a significant reduction in PFKP mRNA abundance in cumulus cells. FGF8 also tended to decrease LDHA mRNA expression, but did not change GLUT1, GLUT4 and PDHA1 mRNA levels in cumulus cells, while it increased PDHA1 mRNA abundance in the oocyte. This study presents novel evidence that FGF8 can slow meiosis progression during IVM in cattle through mechanisms involving reduction of Cyclin B1 expression