中文摘要：

目的探讨促血小板生成素（TPO）途径在人脐血源基质细胞（hUCBDSCs）促进巨核细胞增殖中的作用。方法以巨核细胞系（HEL细胞）作为研究对象,实验分HEL/hUCBDSCs组、HEL/人骨髓基质细胞（hBMSCs）组和HEL悬浮培养组。ELISA法检测hUCBDSCs和hBMSCs培养上清中TPO水平,激光共聚焦显微镜和流式细胞仪检测HEL细胞c-Mpl蛋白表达,RT-PCR检测c-Mpl mRNA表达。结果hUCBDSCs高分泌表达TPO,其分泌高峰在培养第8天,稍迟于hBMSCs;与hUCBDSCs共培养的HEL细胞经流式细胞仪和激光共聚焦检测,均显示其c-Mpl蛋白的表达明显增强（P〈0.05）,但RT-PCR检测结果显示不同培养条件下HEL细胞c-MplmRNA表达无显著性差异（P〉0.05）。结论TPO途径可能是hUCBDSCs促进巨核细胞增殖的重要中间环节,部分机制可能是在翻译或翻译后修饰水平,通过上调TPO受体c-Mpl的表达来实现的。

英文摘要：

Objective To investigate the effects of thrombopoietin （TPO） on the proliferation of megakaryocytic line-HEL cells cocultured with human umbilical cord blood-derived stromal cells （hUCBDSCs）, which is supposed to further elucidate the mechanism of TPO-mediated functions. Methods HEL cells were co-cuhured with hUCBDSCs, and with human bone marrow stromal ceils （hBMSCs）, and suspended HEL was used as control. HEL The concentration of TPO in supernatant of hUCBDSCs and hBMSCs was detected by ELISA assay. The expression of c-Mpl membrane-bound protein of HEIr cells was detected by laser scanning confocal microscopy and flow cytometry, and the expression of c-Mpl mRNA was detected by RT-PCR. Results It was revealed by ELISA assay that the concentration of TPO secreted by hUCBDSCs was higher than that by hBMSCs, even though the passage was done The secretion peak in hUCBDSCs group appeared at the 8th clay of culturing, somewhat delayed to that in hBMSCs group which the peak appeared at the 6th clay. The expression of C-mpl protein displayed uniform green fluorescence on the surface of HEL cell line as determined by laser confocal microscopy, and mean fluorescence intensity detected by flow cytometry was 22. 19±2. 15, 29. 65±0. 82 and 37. 43±1.69 in HEIr suspended culture group, HEL/hBMSCs co-cuhure group and HEL/ hUCBDSCs co-culture group, respectively. The expression of C-mpl protein in HEL/ hUCBDSCs co-culture group was higher than that in the two other groups （P〈0. 05）. No significant differences of the Gmpl mRNA level existed between different groups （P〉0.05）. Conclusion TPO-pathway might be the important intermediate process for hUCBDSCs to promote megakaryocyte proliferation. The promotion as such may be realized by up-regulating the c-Mpl expression in translation or post- translational modification phase.