Decrease of gene expression quality markers in bovine oocyte during winter season

BARRIONUEVO M.G., CORIA M.S., REINERI, P.S., PALMA G.A.

Buenos Aires

Encuentro; Reunión Conjunta de Sociedades de BioCiencias; 2017

Comité Organizador Reunión Conjunta de Sociedades de BioCiencias

Decrease of gene expression quality markers in bovine oocyte during winter seasonBARRIONUEVO M.G.1, CORIA1 M.S., REINERI2, P.S., PALMA1 G.A.(1) INBIONATEC. (2) INTA.The aim of this study was examined seasonal effects on expression of genes playing an essential role in quality of bovine oocyte. Santiago del Estero became in one of the region most important livestock production in Argentina. This region is characterized by wide thermal amplitude with very high temperatures which often exceed 35°C in summer and lower than 13°C in winter. Mammalian oocytes acquire their meiotic competence and fertilization potential in a stepwise manner. As a result, they are potentially exposed to various environmental stressors during follicular development. Folliculogenesis is controlled by growth factors as GDF-9 and BMP-15. The calpain-calpastatin proteases system has been implicated in various cellular signaling pathways including cell cycle regulation and cytoskeleton reorganization. In this work, we analyzed the expression levels of the CAPN1, CAPN2 and inhibitor CAST; BMP15, GDF9 factors and their receptors BMPRI and TGFβR1; GLUT4 and IGF1 as metabolic markers. Bovine ovaries were obtained from a local abattoir from Braford cows during the hot and cold seasons. Cumulus?oocyte complexes (COCs) were aspirated from 3 to 8 mm follicles. The oocytes were pipetted vigorously to ensure that they were fully denuded. To determine cross-contamination we carried out a semi-quantitative PCR using marker genes for oocyte: ZAR, granulosa cells: CYP 19A1 and theca cells: CYP 17A1. Real-time PCRs were carried out with GAPDH and 18S rRNA as reference genes. We found that GDF9, BMP15 and BMPRI mRNA expression decrease in cold season versus hot season. The same pattern was detected for CAPN2 and CAST expression. Meanwhile, TGFβR1, CAPN1, GLUT4, IGF1 expression had no significative differences. Taken together, these results suggest there is a significant decrease in oocyte developmental competence during cold season. It remains to be investigated the direct effect of environmental factors on oocyte quality and its impact on in vitro production efficiency.