对磁粒子标记内皮祖细胞移植至兔颈动脉粥样硬化模型局部行磁共振活体成像的可行性

目的 探讨纳米磁粒子偶联物Fe2O3-PLL标记的内皮祖细胞(EPCs)移植至兔颈动脉粥样硬化模型局部行磁共振活体成像的可行性.方法 制备Fe2O3-PLL,标记分离纯化后得到的兔外周血EPCs,普鲁士蓝染色显示细胞内铁;高脂饮食联合球囊扩张制作兔动脉粥样硬化模型18只,随机分成3组,制模7周后,经股动脉插管分别将标记细胞、未标记细胞及等量生理盐水移植至模型兔右侧颈动脉局部,在移植前、移植后1、7、14天行MR活体成像,测量血管腔内信噪比(SNR),并与细胞移植后各时间点血管组织切片的普鲁士蓝染色比较.结果 普鲁士蓝染色显示蓝色铁颗粒位于EPCs胞浆内,Fe2O3-PLL对EPCs的标记率接近100%;与移植前相比,标记细胞移植组、未标记细胞移植组和对照组移植后各时间点的SNR差异均无统计学意义.血管组织的普鲁士蓝染色结果显示,仅移植后1天的血管局部可见少量蓝染颗粒.结论 在动脉粥样硬化形成过程中移植EPCs,不能使其在局部停留.

Feasibility of MRI of magnetically labeled endothelial progenitor cells in rabbit carotid artery atherosclerosis with local transplantation

Objective To evaluate the feasibility of the magnetic iron oxide (called Fe₂O₃-PLL) labeled endothelial progenitor cells (EPCs) transplanted to rabbit carotid artery atherosclerosis model locally and performing MRI in vivo. Methods Fe₂O₃-PLL were prepared. Rabbit peripheral EPCs were labeled, isolated and purified. Prussian blue staining was performed to show intracellular iron. Atherosclerotic lesions were induced in the right carotid arteries with balloon endothelial injury and high cholesterol feeding. Eighteen adult New Zealand white rabbits were divided into three groups. After 7 weeks of model building, cells allotransplantation was performed via femoral arterial cannula to the right carotid artery with magnetically labeled or unlabeled EPCs and equal normal saline. Serial MRI were performed before and on the 1 st, 7 th and 14 th day after transplantation. Intraluminal signal to noise ratio (SNR) of the right carotid artery on MRI was measured and compared. MRI findings were compared to histological Prussian blue staining at every time point. Results Iron-containing intracytoplasmic vesicles could be observed clearly with Prussian blue staining and Fe₂O₃-PLL labeling efficiency was almost 100%. Intraluminal SNR of the right carotid artery among three groups before and on the 1 st, 7 th and 14 th day after transplantation showed no significant difference. Results of histological Prussian blue staining of blood vessel showed that only few labeled EPCs adherence to impaired endothelium on the 1 st day after transplantation. Conclusion During the course of formation of atherosclerosis, EPCs can not adhere to local region.