SPIO标记浓度对BMSC_s生物学特性的影响及体外MRI表现

Biological characteristics and MR imaging features of SPIO labeled BMSC_s in vitro

目的：观察不同浓度超顺磁性氧化铁（SPIO）标记对干细胞生物学特性的影响及SPIO标记后BMSCs体外的MRI特征。材料与方法分离、培养SD大鼠的BMSCs，取第四代的BMSCs，通过流式细胞仪检测表面抗原。不同浓度的SPIO标记液标记BMSCs，通过普鲁士兰染色检测标记效率，台盼兰活细胞计数检测细胞活力，MTT法检测细胞增殖活性。通过MRI检查，观察体外不同浓度SPIO标记细胞的信号变化情况。结果 SPIO在25～50μg/ml的浓度范围可以安全、高效地标记BMSCs，不会影响BMSCs的表型、活力和增殖等生物学特性；当SPIO浓度在75μg/ml以上时，BMSCs活性及增殖能力逐渐降低。随着SPIO标记浓度的增加，细胞内摄入的铁逐渐增多，而T2信号强度则逐渐降低；当SPIO浓度≥50μg/ml，标记细胞的T2信号强度与普通BMSCs相比较均有明显差异（P〈0.05）。结论适当浓度的SPIO标记BMSCs对其生物学活性没有明显影响，且MRI扫描能够有效检测其信号变化。

Objective：To observe the biological characteristics of rat bone marrow mesenchymal stem cells （BMSCs） labeled by superparamagnetic iron oxide （SPIO） in vitro, and to observe the magnetic resonance imaging （MRI） features of labeled BMSCs in vitro. Materials and Methods： BMSCs were isolated and cultured by plastic adherence method. The BMSCs of the fourth passage were identiifed by speciifc surface antigens by flow cytometr. BMSCs were labeled with SPIO of different concentrations. Trypan blue staining and MTT test to evaluate the effects of SPIO on cell labeling efficiency, cell viability and cell proliferation. The MRI imaging features of labeled BMSCs were observed by MRI scanning. Results：The labeling efifciency of all SPIO groups was about 99%. BMSCs labeled with SPIO-PLL at the concentrations （25, 50 μg/ml SPIO, and 0.75 μg/ml PLL）, Cell viability rates were about 95%. While at the concentration of SPIO （75, 100μg/ml）, cell viability rate was 92.7%and cell proliferation was significantly inhibited （P〈0.05）. On MRI imaging, with the concentration of SPIO increasing, signal intensity decreased gradually. When SPIO concentration ≥50 μg/ml, T2 signal intensity of labeled cells compared with normal BMSCs were significantly different （P〈0.05）. Conclusions：The appropriate concentration of SPIO could not influence on cells biological characteristics. MRI scanning can show the SPIO nanoparticles labeled rat BMSCs significantly and effectively.