Expressão de genes candidatos para a aquisição da competência ovocitária em bovinos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The success of the various assisted reproductive techniques depends on oocyte competence. However, the factors involved on its acquisition and the molecular attributes of competent oocyte are generally unknown. In an attempt to assess genes related with oocyte competence we quantify transcripts for candidate genes in oocytes (H1Foo, H2A, H3A, GHR, GDF9, BMP15, OOSP1) and cumulus cells (FSHR, EGFR, GHR, PTX3, IGF-II) of different levels of competence. Follicles were dissected and distributed according to their diameter into 4 groups: (1) 1.0 to 3.0 mm; (2) 3.1 to 6.0 mm; (3) 6.1 to 8.0 mm; (4) ≥ 8.1 mm. The COCs were released, morphologically classified, matured, fertilized and cultured in vitro or denuded for diameter measurements. The denuded germinal vesicle oocytes and their correspondent cumulus cells were used for gene expression analysis by RT-qPCR. Blastocyst rate was higher for the oocytes recovered from follicles >6 mm than the other two groups, confirming that follicles size is a good model to study competence. In the oocyte, only H2A transcript increased gradually according to follicle size, being greater (P<0.05) in oocyte originated from follicles ≥8.1 mm than those lower than 6.0 mm. Of the 5 genes evaluated in the cumulus cells, 3 (FSHR, EGFR and GHR) showed differences in mRNA level, increasing according to follicular size. In conclusion, we confirmed the critical implication of H2A on developmental competence, and identify important genes in cumulus cells which are associated with oocyte competence and can reflect its quality.

ASSUNTO(S)

expressão gênica células do cumulus oocyte zoologia ovócito gene expression cumulus cell

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