磁标记大鼠神经干细胞移植入脑缺血大鼠的磁共振示踪

目的]使用菲立磁（Feridex）体外标记胎鼠神经干细胞（neural stem cells，NSCs），并在移植脑缺血大鼠后进行活体MRI示踪观察。方法]分离、培养大鼠胚胎源性神经干细胞，使用“Feridex-多聚赖氨酸复合物（FE-PLL）” ，标记神经干细胞，对标记细胞分别进行普鲁士蓝染色、电镜观察，将FE-PLL标记神经干细胞分别移植人脑缺血大鼠左右侧脑室内，活体移植后1、5、14d体内MRI示踪。结果]菲立磁可以高效率地标记神经干细胞，普鲁士蓝染色显示FE-PLL标记神经干细胞胞质内出现细小的蓝色铁颗粒。电镜结果显示FE-PLL标记的神经干细胞胞质内含有许多包裹铁颗粒的囊泡。MRI检查发现脑内移植的标记细胞在磁共振上呈明显的低信号改变。结论]菲立磁可以用来体外标记神经干细胞，利用MRI技术可以对脑内移植后的标记细胞进行初步的活体追踪。

In vivo tracking of neural stem cells labeled with feridex after cerebral ischemia in rats by magnetic resonance imaging

Objective] To label the neural stem cells （NSCs） with Feridex （FE）, and to track the labeled cells with MRI in vivo after transplanted into ischemic rat. Methods] Culture, passage and differentiation of NSCs were completed from embryonic rats, NSCs colabeled with Feridex mediated by poly. L. lysine （FE-PLL）. After the formation of neurospheres, Prussian blue staining was conducted and identifyied the iron particles in these neural stem cells with transmission electron microscopy. NSCs were injected into the left and right lateral ventricle of ischemic rat, and FE-labeled cells were tracked with MRI in vivo 1 day, 5 days and 14 days after transplantation. Results] Feridex could label the NSCs with high efficiency, Prussian blue staining showed numerous blue-stained iron particles. Transmission electron microscopy revealed the presence of numerous vesicles filled with electron-dense magnetic iron particles in the FE-PLL-labbeled NSCs. Conclusions] FE can be used to label NSCs in vivo, the labeled NSCs can be tracked in vivo with MRI.