超顺磁性氧化铁标记骨髓间充质干细胞移植治疗大鼠脑梗死的在体磁敏感加权成像研究

In-vivo susceptibility weighted imaging study of superparamagnetic iron oxide-labeled bone marrow mesenchymal stem cells transplanted in cerebral ischemic rats

目的 超顺磁性氧化铁（SPIO）体外标记骨髓间充质干细胞（BMSC）移植治疗大鼠脑梗死,使用磁敏感加权成像（SWI）监测BMSC在脑内的分布与迁移.方法 原代培养大鼠BMSC,SPIO体外标记第3代BMSC,倒置显微镜及普鲁士蓝染色观察.改良Longa法制作大鼠左侧脑梗死模型,缺血对侧顶叶脑皮层移植SPIO标记的BMSC.分别在移植后1d、1周、2周和4周进行SWI序列MRI动态观察,移植后4周脑组织普鲁士蓝染色观察.结果 移植后1d、1周、2周和4周SWI序列MRI检测均可显示缺血对侧半球移植的SPIO标记BMSC所致的低信号；移植后2周可见沿胼胝体腹侧走行的线状低信号影；移植后4周移植细胞所致的“彗星状”改变更为明显,彗星尾向缺血侧延伸.移植后4周脑组织切片普鲁士蓝染色显示胼胝体内迁移的蓝染细胞呈条带状排列.结论 SWI序列可显示移植部位SPIO标记BMSC所致的低信号,且可以明确显示其在大鼠脑组织内的迁移.

Objective To monitor the distribution and migration of superparamagnetic iron oxide（SPIO）-labeled bone marrow mesenchymal stem cells （BMSCs） transplanted in cerebral ischemic rats byusing susceptibility weighted imaging （SWI）.Methods The third-passage BMSCs primarily cultivated invitro,labeled with SPIO and studied under inverted microscopy after.Prussian blue staining.Left cerebralischemic rats models were established with modified Longa＇ s method.BMSCs were grafted stereotacticallyinto contralateral parietal cortex of these rats.All the rats underwent MRI with SWI sequence at 1 day,1week,2 weeks and 4 weeks after implantation.Brain tissues of the rats were studied with Prussian bluestaining at 4 weeks after transplantation.Results Low-intensity signals which caused by SPIO-labeledBMSCs could be noted at contralateral cerebral hemisphere on SWI at 1 day,1 week,2 weeks and 4weeks after implantation.At week 2,low-intensity linear signals were detected along the ventral aspect ofcorpus callosum.At week 4,MRI results showed conspicuous “comet tails” caused by BMSCs implantationwhich extended to the ischemic side.Prussian blue stained pathology demonstrated blue- stained cellsarranged in bands within corpus callosum.Conclusion MRI with SWI sequence provides not only cleardisplay of low intensity signal caused by SPIO-labeled BMSCs,but also the migration of implanted BMSCs inbrain tissue of rats.