大鼠间充质干细胞对肝肿瘤趋向性及其间质的影响

Study of bone mesenchymal stem cells tropism for hepatic tumors and effect on the form of tumor stromal

目的探讨大鼠骨髓间充质干细胞（BMSC）在体内对肝肿瘤微环境的趋向性以及BMSC对肝肿瘤间质的影响。方法获取大鼠BMSC，分离、培养、扩增。应用超顺磁氧化铁（SPIO）颗粒标记细胞，普鲁士蓝染色鉴定。应用walker-256细胞株肝内种植制备大鼠肝肿瘤模型。实验分为两个实验组，（1）肿瘤成块后BMSC干扰组：肝内种植walker-256细胞6～8d后，磁共振（MR）观察肝内成瘤后，大鼠尾静脉植入磁性标记的BMSC；（2）肿瘤成块前BMSC干扰组：肝内种植walker-256细胞3d后，MR观察肝内未成瘤的大鼠，于尾静脉植入磁性标记的BMSC；一个单纯肝内种植肿瘤细胞的对照组。实验组分别在BMSC移植前及移植后5、10及15d行MR扫描，每次成像后处死若干大鼠，取出肝脏及肿瘤组织分别行HE染色、普鲁士蓝染色，取BMSC移植后第10天的实验组大鼠及相应对照组大鼠组织行血管内皮生长因子（VEGF）、CDS1、vWF免疫组化染色。结果BMSC普鲁士蓝染色表明BMSC的磁标记率达90％。移植后第5、10天，实验组MR扫描T2WI显示肿瘤边缘出现结节状低信号，移植后第15天无明显低信号，对照组肿瘤信号无明显变化。普鲁士蓝染色显示移植后5、10及15d肿瘤边缘及瘤内有蓝染的BMSC颗粒。移植后第10天，两个实验组的VEGF、CD31、vWF的表达均高于对照组（F=34．05，P〈0．01；F=84．24，P〈0．01；F=7．08，P〈0．05）。结论大鼠BMSC在活体内对肝肿瘤有明显的趋向性，并在肝肿瘤内促进血管内皮的生成。

Objective To investigate the tropism capacity of the rat bone mesenehymal stem cells （BMSC） for hepatic tumors microenvironment and the effect on the form of tumor stromal. Methods Rat BMSC were isolated, cultured and expanded, then incubated with superparamagnetic iron oxide （SPIO） nanoparticles. Prussian blue stain was performed for showing intracellular irons. Walker-256 cells were injected into the rat livers directly to establish hepatic tumor models. The experiment was divided into two experimental groups （the group venous injected with BMSC after tumors becoming mass： tail venous injected with BMSC after MR showed the presence of tumors at 6-8 days after operation and the group venous injected with BMSC before tumors becoming mass： tail venous injected with BMSC when MR showed no presence of tumors at 3 days after operation） and one control group. To the experimental groups animals, MRI was made before venous injection of BMSC and at 5,10,15 days after BMSC transplantation. The rats were killed at corresponding period. The pathologic examinations were analyzed, including HE, Prussian blue stain. The expression of vascular endothelial growth factor （ VEGF）, CD31, yon Willebrand factor （vWF） in the specimens harvested at 10 days after BMSC transplantation were detected immunohistochemically. Results Prussian blue staining of SPIO labled BMSC demonstrated cells could be effectively labeled and the labeling efficiency was almost 90%. After BMSC transplantation, two experimental groups were showed tuberculous signal intensity loss at the margin of tumors on T2 weighted MR images at 5,10 days after transplantation and the signal intensity loss was not visualized at 15 days after transplantation. The control group was not observed sig, al intensity decrease. Prussian blue staining of histological analysis showed blue - stained iron particles distributed at the margin of tumor at 5,10, 15 days after transplantation. Immunohistochemicalexamination showed that the expression of VEGF, CD31, vWF in two experimental groups at 10 days after transplantation were higher than that in the control group （ F = 34.03, P 〈 0. 01 ; F = 84. 24, P 〈 0. 01 ; F = 7.08 ,P 〈0. 05）. Conclusion Rat BMSC have the ability to migrate towards hepatic tumors in vivo and promote to form vascular endothelium.