Boutry Sébastien, Brunin Stéphanie, Mahieu Isabelle, Laurent Sophie, Vander Elst Luce, Muller Robert N
Department of General, Organic and Biomedical Chemistry, NMR and Molecular Imaging Laboratory, University of Mons-Hainaut, Mons, Belgium.
Contrast Media Mol Imaging. 2008 Nov-Dec;3(6):223-32. doi: 10.1002/cmmi.256.
Small particles of iron oxide (SPIO) and ultrasmall particles of iron oxide (USPIO), inducing a strong negative contrast on T(2) and T(2)*-weighted MR images, are the most commonly used systems for the magnetic labeling of cultured cells and their subsequent detection by magnetic resonance imaging (MRI). The purpose of this work is to study the influence of iron incubation concentration, nanoparticle size and nanoparticle coating on the magnetic labeling and the viability of non-phagocytic adherent cells in culture. The magnetic labeling of 3T6 fibroblasts was studied by T(2)-weighted MRI at 4.7 T and by dosing-or cytochemical revealing-of iron through methods based on Perl's Prussian blue staining. Cells were incubated for 48 h with increasing iron concentrations of SPIO (25-1000 microg Fe/ml Endorem. Sinerem, a USPIO (20-40 nm) coated with neutral dextran, and Resovist (65 nm), a SPIO bearing an anionic carboxydextran coating, were compared with Endorem (dextran-coated, 80-150 nm) as magnetic tags. The iron loading of marrow stromal cell primary cultures (MSCs) isolated from rat femurs was compared with that of 3T6 fibroblasts. The SPIO-labeling of cells with Endorem was found to be dependent on the iron incubation concentration. MSCs, more sparsely distributed in the culture, exhibited higher iron contents than more densely populated 3T6 fibroblast cultures. A larger iron loading was achieved with Resovist than with Endorem, which in turn was more efficient than Sinerem as a magnetic tag. The magnetic labeling of cultured non-phagocytic adherent cells with iron oxide nanoparticles was thus found to be dependent on the relative concentration of the magnetic tag and of the cells in culture, on the nanoparticle size, and on the coating type. The viability of cells, estimated by methods assessing cell membrane permeability, was not affected by magnetic labeling in the conditions used in this work.
氧化铁微粒（SPIO）和超小氧化铁微粒（USPIO）在T(2)加权和T(2)*加权磁共振成像（MR）图像上产生强烈的负性对比，是培养细胞磁性标记及随后通过磁共振成像（MRI）进行检测最常用的系统。本研究的目的是探讨铁孵育浓度、纳米颗粒大小和纳米颗粒包被对培养的非吞噬性贴壁细胞磁性标记及活力的影响。通过4.7 T的T(2)加权MRI以及基于Perl普鲁士蓝染色的方法对铁进行定量或细胞化学显色，研究了3T6成纤维细胞的磁性标记。将细胞与浓度递增的SPIO（25 - 1000 μg Fe/ml Endorem）孵育48 h。比较了用中性葡聚糖包被的USPIO（20 - 40 nm）Sinerem和带有阴离子羧基葡聚糖包被的SPIO Resovist（65 nm）与作为磁性标记物的Endorem（葡聚糖包被，80 - 150 nm）。比较了从大鼠股骨分离的骨髓基质细胞原代培养物（MSC）与3T6成纤维细胞的铁负载情况。发现用Endorem对细胞进行SPIO标记依赖于铁孵育浓度。在培养中分布较稀疏的MSC比分布较密集的3T6成纤维细胞培养物表现出更高的铁含量。Resovist比Endorem实现了更大的铁负载，而Endorem作为磁性标记物又比Sinerem更有效。因此发现，用氧化铁纳米颗粒对培养的非吞噬性贴壁细胞进行磁性标记依赖于磁性标记物和培养细胞的相对浓度、纳米颗粒大小以及包被类型。在本研究使用的条件下，通过评估细胞膜通透性的方法估计细胞活力不受磁性标记的影响。
