人胎盘间充质干细胞的磁性标记及MR分子成像

Magnetic Labeling and MR Molecular Imaging of Human Placental Mesenchymal Stem Cells

目的探讨多聚赖氨酸-超微超顺磁性氧化铁(PLL-USPIO)标记人胎盘间充质干细胞(hPMSCs)并行MR分子成像的可行性。材料与方法制备浓度为10μg/ml的PLL-USPIO标记hPMSCs,考察标记效率,并检测细胞活性、增殖能力及凋亡率等生物学特性。建立不同数量级细胞琼脂糖凝胶模型,应用3.0T MR分别以T2WI、T2mapping、T2^*mapping序列扫描比较MR横向弛豫时间及弛豫率。结果普鲁士蓝染色显示标记率>95%,标记细胞与未标记细胞活性差异无统计学意义(X^2=0.245,P=0.63)。标记细胞增殖能力在第1天、第3天、第5天与未标记细胞比较,差异均无统计学意义(P>0.05)。未标记细胞和标记细胞晚期凋亡率分别为4.2%和6.0%,差异无统计学意义(X^2=0.87,P=0.35);两组细胞早期凋亡率分别为5.9%和13.1%,差异无统计学意义(X^2=2.85,P=0.91)。当标记细胞数量为1×10^4个时,T2^*mapping序列即可显示,且对应R2^*值大于R2值。结论PLL-USPIO可有效标记hPMSCs,在一定范围内对细胞的生物学特性无明显影响。3.0T MR可实现h PMSCs的体外成像,其中T2^*mapping序列较T2WI、T2mapping序列更敏感。

Purpose To explore the feasibility of magnetic labeling and MR molecular imaging in human placental mesenchymal stem cells(hPMSCs)labeled with polylysine-ultrasmall superparamagnetic iron oxides(PLL-USPIO).Materials and Methods hPMSCs labeled with PLL-USPIO with concentration of 10μg/ml was prepared,the labeling efficiency and detect the biological characteristics of the labeled cells,such as viability,proliferation and apoptosis were investigated.Then agarose gel models with different numbers cells were established,3.0T MR on T2WI,T2mapping and T2*mapping sequences were performed to compare the transverse relaxation time and relaxivity.Results Prussian blue staining showed the labeling rate was more than 95%.There was no significant difference in the activity between labeled cells and unlabeled cells(X^2=0.245,P=0.63).Compared with unlabeled cells,there was no significant difference in the proliferation ability of labeled cells on day 1,3 and 5(P>0.05).The late apoptosis rates of unlabeled cells and labeled cells were 4.2%and 6.0%,respectively,the difference was not statistically significant(X^2=0.87,P=0.35);the early apoptosis rates of the two groups were 5.9%and 13.1%,respectively,without significant difference(X^2=2.85,P=0.91).When the number of labeled cells was 1×10^4,the T2^*mapping sequence could be displayed,and the corresponding R2^*value was much larger than the R2 value.Conclusion PLL-USPIO can effectively label hPMSCs without affecting the biological characteristics of cells within a certain range.3.0T MR can realize in vitro imaging of hPMSCs,in which T2^*mapping sequence is more sensitive than T2WI and T2mapping sequences.