Objective: To study the safe concentration of superparamagnetic iron oxide particles with poly-l-lysine (SPIO-PLL) labelling rabbit adipose stem cells (ADSCs) and quantative T2*mapping imaging. Materials and Methods: The cells labelled with 25, 50, 75 μg/ml SPIO-PLL were detected by Prussian blue staining and transmission electron microscopy (TEM). The cell cycle and apoptosis were analysed by flow cytometry (FCM). 1×106 cells unlabelled and 1×106 cells (labelled 1 d), 1×106 (labelled 3 d) and 5×105 (labelled 1 d) with 25 μg/ml SPIO-PLL were performed with GRE T2*WI and T2*mapping sequences scanning, then the relaxation time of each tube were measured. Results: The results of Prussian blue staining showed the labelled rate was nearly 100%, and TEM displayed particles existed in every cytoplasm. The blocking rate of cell cycle and the rate of cell apoptosis of cells labelled with 25 μg/ml SPIO-PLL had no significant difference compared with the blank group (P>0.05), 25 μg/ml SPIO-PLL was the safe concentration. The signal intensity (SI) of 1×106 cells (labelled 1 d) was the lowest. The T2* relaxation time of each labelled groups had significant difference compared with the blank group (F=169.837, P0.05),25μg/ml磁探针为安全标记浓度;1×106个(1 d)信号强度最低,各组磁标记细胞T2*弛豫时间与对照组比较有明显统计学差异(F=169.837,P<0.01).结论?25μg/ml磁探针能安全高效标记ADSCs并可行体外MR成像,T2*mapping技术能定量监测磁标记细胞的弛豫时间.
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