大鼠蛛网膜下腔移植超顺磁性氧化铁纳米离子标记永生化神经前体细胞后的磁共振成像追踪

目的观察大鼠蛛网膜下腔移植超顺磁性氧化铁纳米粒子（SPIO）标记永生化神经前体细胞后的磁共振成像追踪。方法用SPIO-多聚赖氨酸复合物（SPIO-PLL）标记永生化神经前体细胞。采用普鲁士蓝染色鉴定SPIO-PLL标记永生化神经前体细胞的效率，采用MTT法检测标记前后细胞活力，用免疫细胞化学法对标记后1周的细胞进行抗巢蛋白、微管相关蛋白和胶质纤维酸性蛋白（GFAP）染色，检测标记细胞的分化能力。蛛网膜下腔置管成功的SD大鼠10只，随机分为2组（n=5），标记细胞组和未标记细胞组，蛛网膜下腔分别移植标记后2d的永生化神经前体细胞和未标记细胞，移植后30min及移植后1周用MRI对蛛网膜下腔的细胞进行活体追踪，用组织切片进行普鲁士蓝染色和抗猿肾病毒40大T抗原染色。结果SPIO可以高效率地标记永生化神经前体细胞，普鲁士蓝染色显示SPIO—PLL标记永生化神经前体细胞质内出现细小的天蓝色铁颗粒，SPIO-PLL标记对永生化神经前体细胞的活力没有明显的影响，标记后1周，抗巢蛋白、微管相关蛋白染色阳性，GFAP染色阴性。标记细胞组移植后30min及移植后1周MRI活体检查发现标记细胞在磁共振成像上呈明显的低信号改变，脊髓组织学切片结果普鲁士蓝、抗猿肾病毒40大T抗原染色阳性；未标记细胞组磁共振成像上无明显低信号改变。结论利用MRI技术可以对蛛网膜下腔移植后的标记细胞进行活体追踪。

Detection of superparamagnetic iron oxide-labeled immortalized rat neural progenitor cells in subarachnoid space by MRI

Objective To evaluate the effectiveness of labeling immortalized rat neural progenitor cells with superparamagnetic iron oxide (SPIO) in vitro and the possibility of detecting the labeled cells in the subarachnoid space of rats after transplantation by MRI.Methods Immortalized rat neural progenitor cells were labeled with superparamagnetie iron oxide-poly-L-lyeine (SPIO-PLL) by means of receptor-mediated endoeytosis in vitro.Prussion blue staining was used to identify the iron particles in these neural stem cells.The viability of the labeled cells was measured by MTT.The nestin,microtubnle-associated protein-2 (MAP-2) and fibrillary acidic protein (GFAP) in the labeled cells were detected by immuno-cytochemistry to measure the ability of the labeled cells to differentiate.PE-10 (ID=0.3 mm) was inserted through foramen magnum into subaraehnoid space and advanced caudalward for 7-8 cm with the tip positioned at lumbar region.Ten rats successfully catheterized were randomly divided into 2 groups:labeled cell group and unlabeled cell group.Labeled and unlabeled cells were injected through catheter into the lumbar region of the subarachnoid space.1.7T MRI scanner was used to trace the labeled and unlabeled cells in subarachnoid space 30 min and 1 week after cell transplantation.The animals were then killed and the transplanted cells in spinal cord tissue were detected by Prussian blue staining and immuno- cytochemistry staining with SV40 Tag.Results Prussian blue staining showed numerous blue-stained iron purticles in the cytoplasm of SPIO-labeled immortalized rat progenitor cells.There was no difference in the viability of the cells as measured by MTT between the labeled and unlabeled cells.One week after the cells were labeled with SPIO,nestin and MAP-2 were positively stained while GFAP was negatively stained by immuno-cytochemistry and there was no difference between the labeled and unlabeled cells.30 min and 1 week after transplantation of labeled cells MRI showed a local low signal on T_2 in subarachnoid space.Prussian blue staining and immuno-cytochemistry staining (with SV4OTag) positive cells were found in spinal cord tissue.Conclusion The labeled cells transplanted in rat subarachnoid space can be tracked by MRI.