Estabilidade de genes de referência e expressão das proteínas Morfogenéticas Ósseas (BMPs), receptores de BMP e mensageiros intracelulares (SMADS) em folículos ovarianos caprinos

Abstract

The aims this study to evaluate the stability of reference genes and the expression of bone morphogenetic protein (BMP-2, 4, 6, 7 and 15), their receptors (BMPR-IA, IB and II) and intracellular messengers (SMADs- 1, 5 and 8) in goat follicles before and after culture for 18 days. To evaluate the stability of reference genes and the expression of BMPs, receptors and SMADs, follicles of approximately 0.2, 0.5 and 1 mm were mechanically isolated from goats ovaries. In addition, approximately 0.2 mm follicles were isolated and cultured for 18 days in culture medium supplemented with FSH. Both fresh and cultured follicles were subjected to total RNA extraction and synthesis of cDNA, the quantification of mRNA was carried out by real-time PCR using specific primers for genes of reference (GAPDH, β-tubulin, β-actin, PGK, UBQ, RPL - 19, rRNA18S) and BMPs (2, 4, 6, 7 and 15) receptors of BMPs (BMPR-IA, IB and II) and SMADs (1, 5 and 8). Results showed that β-tubulin and PGK are the most stable reference genes in goats preantral and antral follicles. The messengers RNA for BMP (2, 4, 6, 7 and 15), their receptors (BMPR-IA, IB and II) and Smads (1, 5 and 8) are expressed at different levels in preantral and antral goats, and mRNA expression for BMP-4, BMP-6 and BMP-7 in 1-mm follicles are significantly higher than in follicles of 0.2 and 0.5 mm. However, the levels of mRNA for BMP-2 were reduced in follicles 1 mm, as BMP-15 did not differ between follicular categories. The levels of mRNA for BMPR-IB were higher in follicles of 0.2 mm than in follicles of 0.5 and 1 mm, whereas the mRNA for BMPR-II was significantly higher in follicles than 0.5 mm in follicles of 0.2 to 1 mm. Moreover, mRNA levels for BMPR-1A did not differ between follicles examined. The levels of mRNA for SMAD-5 were significantly higher in 0.2 mm follicles than in follicles of 0.5 and 1 mm. However, follicles of 0.5 mm showed higher levels of mRNA for SMAD-8 than follicles 0.2 and 1 mm. The levels of mRNA for SMAD-1 did not differ between follicles. After the comparisons within each category follicle, BMP-15 expression was higher than BMP-7 in follicles between 0.2 and 0.5 mm. Follicles 0.5 mm in the expression of BMPR-IB was greater than BMPR-II. In all three follicular categories studied, the expression of SMAD-5 was superior to SMAD-8. After culture, follicles showed reduced levels of mRNA for BMP-2, BMP-4, BMP-7, BMPR-IA and SMAD-5. In conclusion, β-tubulin and PGK genes are the two most stable housekeeping for fresh goat follicles 0.2, 0.5 to 1 mm in diameter. BMPs, their receptors and SMADs have specific expression patterns in each category follicular studied. However, in cultured follicles showed a variation in the variation in the expression of BMP system components, differing from in vivo expression of follicles with the same size.