促红细胞生成素基因修饰内皮祖细胞移植治疗下肢动脉闭塞：磁标记MR成像评价

摘要

BACKGROUND:Erythropoietin and progenitor cel transplantation both have therapeutic effects on lower extremity arterial occlusive disease. OBJECTIVE:To investigate the erythropoietin modification effect and magnetic resonance imaging feasibility of superparamagnetic iron oxide (SPIO)-labeled endothelial progenitor cel s in vitro. METHODS:Rat bone marrow-derived endothelial progenitor cel s at logarithmic growth phase were randomized into four groups:endothelial progenitor cel group, SPIO labeled transfection group (pcDNA3-EPO transfection fol owed by SPIO labeling), SPIO labeled empty vector group (empty plasmid transfection fol owed by SPIO labeling), and SPIO labeling group (only SPIO labeling). 4.7T MRI was used to observe SPIO-labeled endothelial progenitor cel s. Cel proliferation, cel cycle distribution, and expression of erythropoietin protein in the four groups were measured. RESULTS AND CONCLUSION:MRI findings showed with the increasing cel number, gradual y lowered signal intensity on T1-weighted imaging (T1WI), T2WI and T2*WI was seen, and the reduction in the signal intensity was the maximum on T2*WI sequence and the minimum on T1WI sequence. For T1WI, T2WI and T2*WI sequences, the minimum number of cel s was 2×104, 1×104 and 0.5×104, respectively. Cel proliferation and cel cycle distribution showed no significant difference among three SPIO labeling groups. In addition, the expression of erythropoietin protein was only found in the SPIO-labeled transfection group. These findings showed that under SPIO labeling, erythropoietin gene-modified endothelial progenitor cel s show no changes in cel proliferation and cel cycle, and the 4.7T MR is capable of imaging SPIO-labeled erythropoietin gene-modified endothelial progenitor cel s in vitro.%背景：促红细胞生成素及内皮祖细胞移植均对下肢动脉闭塞有一定的治疗作用。　　目的：探讨超顺磁氧化铁纳米颗粒(super paramagnetic iron oxide，SPIO)标记的内皮祖细胞体外促红细胞生成素基因修饰效果及体外磁共振成像的可行性。　　方法：将对数生长期的大鼠骨髓来源内皮祖细胞分4组培养，内皮祖细胞组，SPIO标记转染组将pcDNA3-EPO 重组质粒并转染至内皮祖细胞，随后进行SPIO标记；SPIO标记空载病毒组将空质粒转染至内皮祖细胞，随后进行SPIO标记；SPIO标记内皮祖细胞组直接进行SPIO标记。采用4.7 T MR成像SPIO标记的内皮祖细胞；检测4组细胞增殖、细胞周期分布及促红细胞生成素蛋白表达。　　结果与结论：①MR成像：T1WI、T2WI、T2*WI序列均见细胞信号降低，随着细胞数目增多，信号降低逐渐明显；相同数量级细胞，T1WI信号降低最弱，T2*WI信号降低最明显；T1WI、T2WI、T2*WI所能检测到的最小细胞数分别为2×104、1×104、0.5×104；②细胞增殖、细胞周期分布：3组标记内皮祖细胞增殖、细胞周期分布与内皮祖细胞组比较差异均无显著性意义；③促红细胞生成素蛋白表达：仅SPIO标记转染组可见促红细胞生成素蛋白表达；④结果表明：SPIO标记的内皮祖细胞体外促红细胞生成素基因修饰后对细胞增殖、细胞周期无影响，4.7 T MR能够在体外对SPIO标记的促红细胞生成素基因修饰内皮祖细胞成像。