蛛网膜下腔移植SPIO标记的MSCs在大鼠脊髓损伤模型的MR活体示踪研究

目的 将超顺磁性氧化铁纳米粒子(SPIO)标记的骨髓间充质干细胞BMSCs通过蛛网膜下腔置管移植到脊髓损伤大鼠模型,以磁共振成像(MRI)观察其迁移和分布.方法 用携带绿色荧光蛋白的腺病毒(AD5/F35-EGFP)和SPIO标记分离纯化后的BMSCs,免疫荧光和普鲁士蓝染色显示标记效果.制作大鼠脊髓损伤模型,并将蛛网膜下腔置管成功的10只SD大鼠随机分为2组,将标记细胞(实验组,n＝5)和未标记细胞(对照组,n＝5)经蛛网膜下腔移植到模型鼠.在移植前、移植后3、7、14天用3T MRI对移植细胞进行活体示踪,并与损伤脊髓组织切片GFP表达进行对照.结果 AD5/F35-EGFP和SPIO可以高效地标记BMSCs,标记细胞表达绿色荧光,普鲁士蓝染色显示BMSCs胞质内出现蓝色铁颗粒,标记对细胞增殖活力没有明显的影响.蛛网膜下腔移植标记细胞到大鼠脊髓损伤模型,MRI显示损伤区域逐渐增强的T2低信号,组织切片荧光检查与MRI结果一致,未标记细胞组MRI无明显低信号改变.结论 SPIO纳米颗粒可有效标记BMSCs.蛛网膜下腔移植的BMSCs可迁移到脊髓损伤区域;利用MRI可对移植细胞进行活体示踪.

In vivo MR tracking of subarachnoid space grafted magnetically labeled mesenchymal stem cells in rat spinal cord injury models

Objective To evaluate the effectiveness of labeling bone marrow mesenchymal stem cells (BMSCs) with superparamagnetic iron oxide (SPIO) in vivo and the possibility of tracking the labeled cells with MRI after via subarachnoid space grafting. Methods BMSCs were double labeled with AD5/F35-EGFP and SPIO. The labeling efficiency was evaluate with immunofluorescence and Prussian blue stain. Rat spinal cord injury models were made and the micro tubes were inserted into subarachnoid spaces. Ten SD rats were randomly divided into 2 groups. Five rats received GFP-SPIO labeled cells via subarachnoid spaces, the others received unlabeled cells. Serial 3T MRI were performed before and 3, 7, 14 days after transplantation and compared with GFP expressing in tissue slices of injured spinal cord. Results BMSCs could be effectively labeled by AD5/F35-EGFP and SPIO, labeled cells express green fluorescence and iron containing intracytoplasmtic vesicles could be observed clearly with Prussian blue staining. There was no difference in the viability between labeled and unlabeled cells. After grafting via subarachnoid space, hypointensity T2 signals could be detected in the injured spinal cord segment on MRI, in which green fluorescent could be detected with immunofluorescence. Conclusion BMSCs could be effectively labeled with SPIO. Labeled BMSCs could migrate to the injured spinal cord segment after grafting via subarachnoid space and could be monitored in vivo with MRI.