干细胞标志分子在猪脐带组织中的表达

Expression of stem cell marker molecules in porcine umbilical cord

【目的】研究干细胞标志分子,如干细胞"干性"调控关键基因及胚胎阶段特异性抗原(Stage-specific embryonic antigen,SSEA)在猪脐带组织中的表达状况,为猪脐带来源细胞的利用提供参考。【方法】以猪脐带为研究材料,利用反转录聚合酶链反应(RT-PCR)和免疫组化方法,分析干细胞"干性"调控关键基因Oct4、Nanog、Sox2、Rex1以及SSEA-1、SSEA-3和SSEA-4在猪脐带组织中的表达。【结果】RT-PCR分析显示,干细胞"干性"调控关键基因Oct4、Nanog、Sox2、Rex1在所有猪脐带样品中阳性转录,但Nanog mRNA的相对表达量显著低于Oct4mRNA、Sox2mRNA和Rex1mRNA,而后三者之间无显著差异;免疫组化分析显示,Oct4、Nanog、Sox2、SSEA-1、SSEA-3和SSEA-4在猪脐带组织中呈阳性染色,表达这些蛋白抗原的阳性细胞主要分布于脐带华通氏胶,且多集中于血管附近。【结论】从基因转录和蛋白水平证实猪脐带组织表达干细胞标志分子,SSEAs表达谱与猪胚胎生殖细胞相符,提示脐带组织中含有早期未分化的多潜能细胞。

[Objective] The present study aimed to evaluate the expression of marker molecules of stem cells and stage-specific embryonic antigens （SSEAs） in porcine umbilical cord. [Method] Porcine umbilical cords were used as the material to analyze the expression of key regulatory genes including Oct4, Nanog, Sox2,and Rexl and SSEAs including SSEA-1, SSEA-3, and SSEA-4 by reverse transcribed polymerase chain reaction （RT-PCR） and immunohistochemical staining. [Result] RT-PCR results demonstrated that all the genes were positively transcribed in all porcine umbilical cord samples and the relative expression of Nanog mRNA was significantly lower than those of Oct4 mRNA, Sox2 mRNA,and Rex1 mRNA,which exhibited similar expression levels. Moreover, immunohistochemical staining showed that the proteins against antibodies of Oct4, Nanog, Sox2, SSEA-1, SSEA-3 and SSEA-4 exhibited positively in tissue sections of all umbilical cord samples,and the positive cells were mainly distributed in the Wharton＇s jelly adjacent to umbilical tubes. [Conclusion] The study affirmed at the level of mRNA and protein that the marker mol- ecules expressed in porcine umbilical cords and SSEAs patterns were consistent with porcine embryonic germ cells, hinting that porcine umbilical cord contained primitively undifferentiated stem cells.