中文摘要：

背景：超顺磁性氧化铁作为磁共振对比剂已进行了大量临床实验,但其随标记细胞传代分化后的分布及代谢却报道甚少。目的：实验首次观察和描述了体外超顺磁性氧化铁标记的大鼠骨髓基质干细胞及其传代细胞的情况,并以磁共振信号检测铁粒子随细胞传代的演变情况。设计、时间及地点：细胞学体外观察,于2006-06/2007-01在川北医学院附属医院医学影像研究所和风湿免疫研究所完成。材料：清洁级雌性大白鼠2只,由川北医学院动物中心提供。超顺磁性氧化铁由德国先灵公司惠赠。方法：抽取大鼠双侧股骨和胫骨的骨髓,采用贴壁法分离纯化骨髓基质干细胞,用铁浓度为42mg/L的氧化铁-多聚赖氨酸复合物600μL进行体外标记。主要观察指标：倒置显微镜下观察各代细胞标记阳性率,磁共振扫描测定磁共振信号强度变化百分率。结果：普鲁士蓝染色后,镜下第1代细胞超顺磁性氧化铁标记阳性率为100%,随着传代次数的增加,第1～5代细胞标记阳性率逐级降低。与未接受超顺磁性氧化铁标记的PBS对照比较,除第1,2代细胞信号强度变化率无明显变化外,随着细胞的传代磁共振信号强度变化百分率逐渐降低,细胞标记率与T2＊WI信号强度呈负性相关（r=-0.9866,P〈0.005）。结论：标记入骨髓基质干细胞内的铁能随细胞的传代而传向子代,并可以在一定时期内用磁共振进行追踪检测,实验结果亦首次提出了磁标记的细胞铁粒子可随细胞传代而递减的规律。

英文摘要：

BACKGROUND：As magnetic resonance （MR） contrast,a large number of clinical and experimental researches have been done on superparamagnetic iron oxide （SPIO）,while the report on the labeled cell passaged cells is rare.OBJECTIVE：MR imaging was performed to the labeled bone mesenchymal stem cells （BMSCs） and its passaged cells in vitro,in order to establish the base of monitoring magnetic labeled BMSCs with magnetic resonance imaging （MRI） in vivo.DESIGN,TIME AND SETTING：The cytological in vitro experiment was performed at the Imaging Research Institute and Institute of Rheumatology and Immunology of North Sichuan Medical College Hospital from June 2006 to January 2007.MATERIALS：Two clean female albino rats （Animal Center,North Sichuan Medical College）,SPIO （Schering AG,Germany） were used in this study.METHODES：Bilateral femur and tibia bone marrow was extracted from rats.BMSCs were harvested and purified using the adherent method,and then labeled with 600 μL ferric oxide-polylysine compound （42 mg/L iron concentration） in vitro.MAIN OUTCOME MEASURES：Cell maker-positive rate and the MR signal intensity were respectively measured to the labeled cells and its passaged cells under the inverted microscope and magnetic resonance imaging.RESULTS：Following Prussian blue staining,labeling rate of SPIO labeled cells at the first passage was 100%.With increased passage,the labeling rate was reduced from the first to fifth passages.Compared with non-labeled PBS control,there was no significant difference in signal intensity in the first and second passages cells,but the signal intensity percentage was gradually decreased with signal intensity of increased cell passage from the third passage.Cell labeling rate was negatively correlated with T2WI signal intensity （r=-0.986 6,P 〈0.005）.CONCLUSION：The iron particles in the magnetic labeled cells can be passaged to the offspring cells,and can be monitored in a certain period of time with MRI in vitro.These results firstly introduced