【摘要】 目的探索脊髓内移植间充质干细胞的活体监测方法。方法从胎儿血分离培养人间充质干细胞,流式细胞分析、免疫荧光染色、放射性配基结合实验检测其转铁蛋白受体的体内外表达。移植于兔正常脊髓后,放射性碘I标记铁饱和转铁蛋白为示踪剂,进行活体闪烁扫描成像和脊髓切片放射自显影(A组);放射性碘标记人血清白蛋白为示踪剂作为非特异显像对照组(B 组);单纯移植磷酸盐缓冲液(PBS)作为移植对照组(C组)。结果体外培养和移植于脊髓第2天的间充质干细胞表达转铁蛋白受体,第10天不表达。移植第2天,活体闪烁扫描成像和脊髓切片放射自显影均显示A组细胞移植部位放射性聚集。B、C组仅见本底影像。A组与B、C组之间在脊髓移植部位的相对放射性(RI／RN)差异均有统计学意义(P<0．05);移植后第10天,3组脊髓内移植部位均未见阳性显像。结论放射性碘标记铁饱和转铁蛋白为示踪剂,进行活体闪烁扫描成像可以示踪到脊髓内移植第2天的间充质干细胞。提供了一种以移植干细胞表面标志为靶点进行核素显像的活体示踪方法。更多还原

【Abstract】 To explore an in vivo radionuclide imaging method to track stem cells transplanted into spinal cord. Methods Human mesenchymal stem cells （hMSCs） were isolated from umbilical cord blood. Flow cytometry assay, immuno-fluorescent staining and receptor binding assay determined TfR expression of hMSCs. Tf saturated with iron and labeled with iodine [¹²⁵I or ¹³¹I-Tf（Fe）₂] were used as tracer. The hMSCs was tracked by scintigraphy in vivo and autoradiography ex vivo after transplanted into rabbit spinal cord. Results TfR expression of hMSCs was demonstrated with flow cytometry assay, immuno-fluorescent staining and binding assay in vitro and ex vivo 2nd after transplantation. On 2nd day after transplantation, accumulation of radioactivity at the hMSCs injection site was detected at 16 hr post 131I-Tf（Fe）₂ injected into subarachnoid space. The comparative experiments with 131I-HSA as tracer and PBS as graft as well as ex vivo autoradiography demonstrated the specificity of ra-diolabeled Tf（Fe）2 uptake of hMSCs in spinal cord. However, On 10th day after transplantation, no positive signal was observed at hMSCs injection site on scintigraphic and autoradiographic images probed with radioiodinated Tf（Fe）₂, immuno-fluorescent staining showed that TfR was scarcely expressed on implanted cells. Conclusion The hMSCs Implanted to spinal cord could be tracked by scintigraphy in vivo with 131I-Tf（Fe）2 as tracer on 2nd day after transplantation. This primary study presents an in vivo imaging method with radiotracers targeting at cellular marks to track stem cells transplanted into body.更多还原