College of Animal Science and Technology, Institute of Animal Biotechnology, Shanxi Agricultural University, Taigu, China.
Andrologia. 2011 Aug;43(4):254-60. doi: 10.1111/j.1439-0272.2010.01062.x. Epub 2011 Mar 23.
The expression and localisation of downstream signalling molecules of transforming growth factor beta superfamily, Smad2 and Smad4 proteins, was investigated in immature and mature dog testis. Cellular localisation of Smad2 and Smad4 proteins was examined using immunohistochemistry. Quantitative analysis of immunostaining was determined by the image analysis system. The specificity of the antibodies was examined using Western blotting assay. Smad2 and Smad4 were widely expressed in the testes, mainly immunolocalised in the cytoplasm of gonocytes, Leydig cells and Sertoli cells of immature testes, and Leydig cells and Sertoli cells of mature testes. At the same time, the expression levels for both proteins were different between immature and mature age groups: the expression of Smad2 and Smad4 proteins in the Sertoli cells of mature testis was higher than in the immature group (P < 0.05), but the expression of these two proteins in Leydig cells of mature testis was weaker than that seen in immature stage (P < 0.05). The temporospatial distribution of Smad2 and Smad4 proteins in testicular cells suggests that these two signalling molecules may play an important role in specific stages of testicular development and spermatogenesis, thus providing direct evidences for transforming growth factor beta action in the dog testis.
转化生长因子β超家族下游信号分子 Smad2 和 Smad4 蛋白的表达和定位在未成熟和成熟犬睾丸中进行了研究。使用免疫组织化学法检测 Smad2 和 Smad4 蛋白的细胞定位。通过图像分析系统确定免疫染色的定量分析。使用 Western blot 分析测定抗体的特异性。Smad2 和 Smad4 在睾丸中广泛表达，主要免疫定位在未成熟睾丸的精原细胞、间质细胞和成腔细胞的细胞质中，以及成熟睾丸的间质细胞和成腔细胞中。同时，两种蛋白质在未成熟和成熟年龄组之间的表达水平也不同：成熟睾丸的支持细胞中 Smad2 和 Smad4 蛋白的表达高于未成熟组（P<0.05），但成熟睾丸间质细胞中这两种蛋白的表达弱于未成熟阶段（P<0.05）。Smad2 和 Smad4 蛋白在睾丸细胞中的时空分布表明，这两种信号分子可能在睾丸发育和精子发生的特定阶段发挥重要作用，从而为转化生长因子β在犬睾丸中的作用提供了直接证据。
