磁共振成像R2*map示踪超顺磁性氧化铁标记的内皮祖细胞

目的 探讨R2*map在超顺磁性氧化铁(SPIO)标记内皮祖细胞(EPCs)定量检测中的价值.方法 分离和培养Balb/c小鼠后肢骨髓来源的EPCs,培养7 d,用细胞膜红色荧光探针标记的乙酰低密度脂蛋白和异硫氰酸荧光素标记的荆豆凝集素-1双阳性染色法,以及异硫氰酸荧光素标记干细胞抗原1和藻红素标记的血管内皮细胞生长因子受体2的方法上流式细胞仪进行鉴定.用50 μg/ml SPIO及6 μl/ml lipofectamine 2000与EPCs共孵育进行标记后透射电子显微镜观察;制成不同细胞浓度(0～2.0×106/ml)标记及未标记SPIO的细胞琼脂糖模型,进行3.0T磁共振扫描,包括T2*map和T2map扫描,得到R2*map和R2map图像.结果 培养7d后细胞呈现内皮祖细胞特征.SPIO标记的EPCs细胞结构与未标记细胞相比较,无明显改变.R2*和R2值与标记SPIO的细胞浓度呈线性相关(r值分别为0.955,0.922,P值均<0.05);R2*效应明显高于R2效应(t=23.23,P<0.05).结论 磁共振成像R2*map扫描可准确定量示踪SPIO标记的EPCs.

MR R2*map for tracing superparamgnetic ironoxides labeled endothelial progenitor cells in vitro

Objective To investigate the value of R2*map for quantitatively tracing superparamgnetic ironoxides(SPIO)labeled endothelial progenitor cells(EPCs).Methods The EPCs were isolated from Balb/c mice bone marrow and cultured in vitro.After 7 days,expression of acetylated low-density lipoprotein (acLDL)and Ulex europaeus agglutinin-1(UEA-1),two markers of EPCs,was observed by double staining using fluoresence mieroseope,the expression of stem cell antigen-1 and vascular endothelial growth factor receptor-2(VEGFR-2)was confirmed by flow cytometry.EPCs were labeled by incubating with 50 μg/ml SPIO and 6 μl/ml lipofeetamine2000,SPIO labeled EPCs were observed under transmission electron micro-scope(TEM).Labeled and unlabeled EPCs were mixed with 10 g/L agrose and scanned using a 3.0T MR scanner,R2* map and R2 map images were obtained on workstation.Result After 7 days of in vitro culture,most of the cells showed characteristics of EPCs.There was no morphological difference between SPIO labeled EPCs and unlabeled EPCs.R2* and R2 values exhibited a linear correlation with the number of labeled cells in the agarose gel.Compared to R2,R2* was a better indicator of the number of labeled cells.Conclusion MR R2* map can be used to trace SPIO labeled EPCs quantitatively.