中文摘要：

目的探讨神经干细胞移植后存活细胞迁徙及分化的无创性监测方法。方法采用超顺磁性氧化铁（SPIO）纳米粒子和5溴2脱氧尿嘧啶核苷（Brdu）在体外对神经干细胞进行双标记，然后移植至大脑中动脉梗死大鼠模型（MCAO）的脑内（健侧）。术后1d以及1、2、3、4、5和6周，采用磁共振仪检测标记细胞的迁徙。第6周磁共振扫描后处死大鼠，依据磁共振成像（MRI）提示的移植细胞迁徙部位切取脑组织，进行普鲁士蓝染色和免疫组织化学染色，观察神经干细胞的迁徙及分化情况。结果移植后3周，MRI显示细胞沿胼胝体迁徙的条带状低信号，并在随后的定期MRI中观察到其向中线移动，脑组织标本普鲁士蓝染色及免疫组织化学染色的阳性位置与MRI结果一致，而且移植的神经干细胞可以分化为星形胶质细胞及神经元。结论MRI可动态监测SPIO标记的神经干细胞移植后在体内的迁徙路径，且对受者无创。

英文摘要：

Objective To explore the migration of transplanted neural stem cells labeled with SPIO with 4. 7T MR system and study cell differentiation by immunohistochemistry in ischemic rats. Methods Rat neural stem cells （NSCs） co-labeled with SPIO mediated by poly-L-lysine and bromodeoxyuridine （BrdU） were transplanted into the middle cerebral artery occlusion （MCAO） rats after 14 days when MCAO model was made successfully. 4. 7T MR scanner was used to monitor the migration of transplanted cells after 1,2,3,4,5 and 6 weeks post-transplantation. After MRI examination at 6th week,the rats were killed and Prussian blue staining and irnmunohistochemistric staining were performed to study migration and functional differentiation of NSCs. Results Three weeks after transplantation, linear hypointensity area derived from migration of labeled NSCs was observed in the corpus callosum adjacent to the injection site. Six weeks after transplantation, linear hypointensity area was moved toward the midline along the corpus callosum. MRI findings were confirmed by Prussian blue staining and immunohistochemical straining. Co-labeled imrnunohistochemical methods demonstrated transplanted NSCs could differentiated into astrocytes and neurons. Conclusion MRI is very useful in demonstrating the migration path of labeled NSCs. Transplanted NSCs into ischemic rats can differentiated into astrocytes and neurons during the process of migration.