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目的探讨超顺磁性氧化铁颗粒(SPIO)标记的胎鼠神经干细胞(NSCs)在脑梗死模型大鼠脑内移植后,MR示踪观察的可行性。方法大鼠脑梗死模型24只,按随机数字表法分为3组第1组大鼠同侧尾状核移植SPIO和5-溴脱氧尿核苷(BrdU)双标记的NSCs;第2组对侧尾状核移植双标记的NSCs;第3组对侧尾状核移植未标记的NSCs。移植后1、3、5、7周后进行MR示踪观察,选择T2WI和梯度回波(GRE)序列,成像后相应时间点每组处死2只大鼠,取脑组织冰冻切片后进行普鲁士蓝染色及BrdU染色。结果移植后1周MRI显示移植标记细胞组在注射点处可见类圆形低信号影,未标记细胞组注射点未见异常信号影;3周后,第1组梗死皮层下可见线状低信号影;移植5周后,第2组沿胼胝体走行可见扇形低信号影,尖端指向病灶。GRE序列显示标记细胞较清晰,而T2WI显示梗死病灶和大鼠脑正常结构较清晰。相应时间点相应部位普鲁士蓝染色及BrdU染色可见阳性细胞,与MRI结果相符。结论超顺磁性氧化铁颗粒和BrdU双标记的神经干细胞移植至大鼠脑内后可迁移到病灶区;MR成像能够在活体内连续示踪观察神经干细胞的迁移及分布情况。
Objective To investigate the feasibility of MR tracing of transplanted rat neural stem cells (NSCs) labeled with superparamagnetic iron oxide particles (SPIO) after intracerebral transplantation in rats with cerebral infarction. Methods Twenty-four cerebral infarction models were divided into three groups according to the random number table. The rats in group 1 were injected with SPIO and 5-bromodeoxyuridine (BrdU) double labeled NSCs. Group 2 Lateral caudate nucleus transplantation of double labeled NSCs; group 3 contralateral caudate nucleus transplantation of unlabeled NSCs. MR tracings were performed at 1, 3, 5 and 7 weeks after transplantation. T2WI and gradient echo (GRE) sequences were selected. Two rats were sacrificed at each time point after imaging. Frozen sections of brain tissue were made into Prussian blue Staining and BrdU staining. Results One week after transplantation, MRI showed that the labeled cells in the transplantation group showed low circular signal at the injection site and no abnormal signal at the injection site in the unlabeled cell group. After 3 weeks, linear low signal After transplanted for 5 weeks, the second group showed a low-signal scallop along the corpus callosum and the tip pointed to the lesion. The GRE sequence showed that the labeled cells were clearer, while the T2WI showed that the infarct lesion and the normal structure of rat brain were clearer. Corresponding time point corresponding Prussian blue staining and BrdU staining positive cells, consistent with the MRI results. Conclusion The superparamagnetic iron oxide particles and double labeled BrdU-labeled neural stem cells can migrate to the lesion area after transplanted into the brain of rats. MR imaging can observe the migration and distribution of neural stem cells continuously in vivo.