量化MRI活体示踪新型顺磁性铁纳米粒子标记SD大鼠脂肪源性干细胞

摘要

目的 探讨MRI活体示踪慢性脑缺血SD大鼠颅内移植聚乙二醇/聚乙烯亚胺修饰的超顺磁性氧化铁(PEG/PEI-SPIO)标记脂肪源性干细胞(ADSCs)的可行性.方法 将双侧颈总动脉永久性结扎6个月后的30只SD雌性大鼠分为PEG/PEI-SPIO标记干细胞移植组(n=15)及未标记干细胞移植组(n=15),向2组模型鼠右侧脑室注射入标记或未标记ADSCs悬液.于移植术后第7天、14天、21天每组各选取5只模型大鼠行颅脑MR成像,于T2-mapping图像上测量2组颞顶叶皮质、海马、小脑的T2值.之后处死动物,对脑组织进行普鲁士染色,于高倍镜下计数蓝染细胞数,对T2值和蓝染细胞数行统计学分析.结果 T2WI、T2* WI、SWI可见2组大鼠颞顶叶皮质及海马散在类圆形低信号区.移植后第14天,标记细胞移植组右侧颞顶叶皮质、右侧海马的T2值较未标记细胞移植组缩短(P=0.013、0.045).移植后第21天,标记细胞移植组右侧颞顶叶皮质T2值较未标记细胞移植组缩短(P=0.007).移植后第14天右侧颞顶叶皮质及右侧海马,第21天右侧颞顶叶蓝染颗粒数量2组间差异有统计学意义(P=0.029、0.043、0.032).结论 于大鼠侧脑室移植PEG/PEI-SPIO标记的ADSCs可向慢性脑缺血所致病变区域迁移;采用量化MRI活体示踪移植PEG/PEI-SPIO标记ADSCs,可评估慢性脑缺血模型大鼠脑内迁移和分布.%Objective To explore the feasibility of tracking migration and distribution of SD-rat adipose derived stem cells (ADSCs) labeled with Polyethylene Glycol/Polyehthyleneimine modified superparamagnetic iron oxide (PEG/PEI-SPIO) in rats with chronic cerebral ischemia using MRI.Methods Thirty female SD rats underwent permanent occlusion of bilateral common carotid arteries 6 months were divided into PEG/PEI-SPIO labeled group and unlabeled group (each n =15).Labeled or unlabeled ADSCs suspension was injected into the right ventricle of rats in two groups,respectively.MR scans were performed at the 7th,14th and 21st day after transplantation for each 5 rats.T2 value of T2mapping sequence in hippocampus,cortex and cerebellum were measured.Then the rats were scarified,and the brains were obtained,and Prussia dyeing was performed.Under high magnification,blue dye cells at each time points and brain area were counted.T2 values and blue dye cells were statistically analyzed.Results Class round hypointensity areas were detected in temporol-parietal cortex and hippocampus in both groups on T2WI,T2* WI and SWI.T2 value of the right temporolparietal cortex and hippocampus in the labeled group was shorter than those of the unlabeled group on the 14th day after transplantation (P=0.013,0.045).T2 value of the right temporol-parietal cortex in the labeled group was shorter than that of the unlabeled group on the 21st day after transplantation (P=0.007).The number of blue dye cell of the right temporol-parietal cortex on the 14th and 21th day,hippocampus on the 14th day in the labeled group were more than those of the unlabeled group after transplantation (P=0.029,0.032,0.043).Conclusion ADSCs labeled with PEG/PEI-SPIO transplanted into lateral ventricle of SD rat could migrate to the damaged areas caused by chronic cerebral ischemia.It is possible to use quantitative MRI to track migration and distribution of ADSCs labeled with PEG/PEI-SPIO in rat brain.