大鼠卵巢发育过程中Smad4的表达(英文)

Expression of Smad4 during rat ovarian development

目的了解转化生长因子-β超家族(TGF-βs)在调节卵泡发育过程中的信号转导模式,以探讨在不同发育阶段大鼠卵巢中Smad4蛋白及mRNA的表达。方法选择不同发育时期大鼠卵巢,运用免疫组化方法检测卵巢中Smad4蛋白表达,并进行图像分析;采用半定量逆转录聚合酶链反应(RT-PCR)方法检测Smad4mRNA在卵巢中的表达,以GAPDH作为内对照与特异性Smad4同时进行扩增,并计算Smad4和GAPDH的RT-PCR产物积分吸光度比值来表示Smad4mRNA的含量。结果Smad4广泛表达于卵巢组织,但主要表达在卵泡中,其表达部位和强度随卵巢的成熟度不同而变化;在卵巢发育早期,Smad4主要在原始卵泡和窦前卵泡中表达,而在间质中的表达较弱;随着卵巢的发育成熟,Smad4在间质中的表达逐渐增强,性成熟后,在窦状及成熟卵泡颗粒细胞和卵泡膜的表达与间质细胞比较无显著差异(P>0.05)。Smad4在卵泡中的表达强度也发生了变化,即随着卵泡的发育,Smad4在窦状及成熟卵泡卵母细胞的表达明显减弱,与窦前卵泡卵母细胞比较有显著差异(P<0.05,P<0.01);与窦前卵泡比较,Smad4在卵泡膜细胞的表达逐渐增强(P<0.01),而在各级卵泡颗粒细胞中的表达无显著差异(P>0.05)。RT-PCR结果显示各阶段卵巢均有mRNA的表达,从第3周起Smad4mRNA的表达明显增强,Smad4和GAPDH积分吸光度比值?

Objective To clarify the signal transduction pathway of transforming growth factor-βsuperfamily (TGF-βs) in the regulation of follicle growth by investigating the expressions of Smad4 protein and mRNA in rat ovaries in different developmental stages. Methods Rat ovaries of different developmental stages were obtained to determine the expression of Smad4 protein by immunohistochemistry and image analysis system, with Smad4 mRNA measured by semi-quantitative RT-PCR. Specific primers of Smad4 and GAPDH (internal control) were used for amplification by RT-PCR, and the ratios of their integrated optical densities were calculated to estimate the relative quantity of Smad4 mRNA expression. Results Smad4 protein was widely expressed in the ovary, mainly in the follicles, and the location and intensity of Smad4 expression varied with the degree of maturation of the ovary. In the early developmental stages, Smad4 protein expressed mainly in the primordial and preantral follicles, but little in the stromal cells, and its expression intensity in the stroma increased gradually in the course of ovarian maturation. After sexual maturity, Smad4 expression intensity varied only insignificantly among the granulosa cells, theca cells and stromal cells of the antral and mature follicles (P>0.05). The staining intensity of Smad4 in the follicles also underwent changes in relation with their development, being less intense in the oocytes of the antral and matured follicles as compared to the preantral follicles (P<0.05 and P<0.01, respectively) but markedly greater in the theca cells of the antral and matured follicles than in the preantral follicles (P<0.01). No significant difference in Smad4 expression was found in the granulosa cells of different developmental stages (P>0.05). RT-PCR demonstrated that Smad4 mRNA was expressed in all the developmental stages of the rat ovary; and from the 3rd week on, the integrated optical density of Smad4 and GAPDH was significantly higher than that in 1-day-old neonatal rats. Conclusion The expression patterns of Smad4 protein and mRNA in rat ovary in the course of its development indicate that Smad signal transduction may play a role in the folliculogenesis.