中文摘要：

背景：上皮细胞是组织工程常用的种子细胞类型,但如何无创性地对其进行体内示踪仍缺乏有效手段。目的：探讨超微超顺磁性纳米氧化铁标记犬口腔黏膜上皮细胞及其体外磁共振成像的可行性。方法：原代培养比格犬口腔黏膜上皮细胞,分别予以0,5,10,25,50,100 mg/L超微超顺磁性纳米氧化铁联合0.75 mg/L多聚赖氨酸标记犬口腔黏膜上皮细胞,普鲁士蓝染色鉴定不同质量浓度梯度下细胞内铁表达情况,CCK-8试剂盒检测各组细胞增殖情况,确定最佳标记质量浓度。最后,将2×10^5个标记上皮细胞置于1 mL PBS缓冲液中重悬,行3.0 T MR T2＊WI序列扫描,测量不同标记质量浓度下MRI灰度值。结果与结论：（1）超微超顺磁性纳米氧化铁联合0.75 mg/L多聚赖氨酸成功标记口腔黏膜上皮细胞,普鲁士蓝染色显示细胞内存在蓝染铁颗粒,且随质量浓度增加,蓝染颗粒增加,至25 mg/L时蓝染率达到饱和;（2）CCK-8法检测结果表明超微超顺磁性纳米氧化铁质量浓度低于25 mg/L时,细胞增殖不受影响;（3）磁共振扫描显示,随着转染质量浓度增加,超微超顺磁性纳米氧化铁标记细胞磁共振信号降低;（4）结果表明,超微超顺磁性纳米氧化铁联合多聚赖氨酸能有效标记犬口腔黏膜细胞,且当转染质量浓度在25 mg/L以下时,不影响细胞增殖,体外磁共振成像显影良好。

英文摘要：

BACKGROUND：Epithelial cel s are commonly used as the seed cel in tissue engineering;however, there is stil a lack of an effective in vivo noninvasive trace technology. OBJECTIVE：To investigate the feasibility of labeling canine oral epithelial cel s with ultrasmal superparamagnetie iron oxide （USPIO） and magnetic resonance imaging （MRI） in vitro. METHODS：Oral epithelial cel s from beagles were primary cultured, and then labeled by 0.75 mg/L poly-L-lysine combined with USPIO （0, 5, 10, 25, 50 and 100 mg/L）, respectively. To determine the optimal dosage, the intracel ular iron expression was identified by Prussian blue staining, and the cel viability in different groups was detected by cel counting kit-8. Final y, 2×10^5 labeled cel s were suspended with 1 mL PBS buffer, and were screened using 3.0 T MR on T2＊WI sequences in vitro. RESULTS AND CONCLUSION：USPIO prepared with 0.75 mg/L poly-L-lysine could successful y label dog oral epithelial cel s. Prussian blue staining showed intracel ular blue spots, and the intracel ular blue spots became more with the concentration increasing and saturated at the concentration of 25 mg/L. Cel counting kit-8 indicated that the cel viability did not change when the concentration〈25 mg/L. Among the T2＊WI sequences, the MRI signal intensity decreased with the concentration increasing. In conclusion, canine oral epithelial cel s can be effectively labeled with USPIO making no impact on cel viability when the concentration〈25 mg/L, and MRI can be used to track these labeled cel s in vitro.