放射性脑损伤模型大鼠脑内移植超顺磁性氧化铁标记神经干细胞MRI示踪研究

Magnetic resonance tracking of transplanted neural stem cells labeled with superparamagnetic iron oxide nanoparticles in rats with whole brain irradiation

目的 探讨超顺磁性氧化铁颗粒标记的神经干细胞(NSC)在放射性脑损伤大鼠模型脑内移植后,磁共振成像(MRI)示踪观察的可行性。方法 建立放射性脑损伤模型大鼠16只,4周后将磁化标记的NSC立体定向植入模型大鼠海马区。移植后1、2、4、8周行4.丌MRI干细胞示踪观察,选择T_1WI、T_2WI和梯度回波(GRE)序列。移植后1、8周处死大鼠,取脑组织冰冻切片后进行普鲁士蓝染色。结果 移植后MRI显示大鼠注射点处可见类圆形低信号影;GRE序列显示标记细胞较清晰,而T_2WI显示大鼠脑正常结构较清晰。移植后1、8周移植部位普鲁士蓝染色可见阳性细胞,与MRI结果相符。结论 MRI能够在放射性脑损伤大鼠脑内活体连续示踪观察NSC的迁移及分布情况。

Objective To explore the feasibility of labeling neural stem cells （NSCs） with superparamagnetic iron oxide （SPIO） particles in tracking the labeled cells after transplantation into rats with whole brain irradiation. Methods Irradiation injury was induced in 16 female Sprague-Dawley rats by whole brain irradiation. Four weeks after irradiation neural stem cells derived from the brain of 14-d embryonic rats and co-labeled with SPIO and poly-L-lysine were transplanted in the brain of irradiated rats. 4.7T MRI scanning was performed to monitor the transplanted cells after 1, 2, 4, 8 weeks. Two rats were sacrificed at week 1 and 8 after transplantation and Prussian blue staining on the brain sections performed. Results The areas with transplanted labeled neural stem cells were presented as hypointense zone on MR images. Prussian blue staining showed labeled cells in the transplanted hippocampus area. Conclusion MRI as a noninvasive procedure is useful for tracking the location and distribution of labeled neural stem ceils in rats with whole-brain irradiation.