Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, Maryland, United States of America.
PLoS One. 2009 Aug 21;4(8):e6712. doi: 10.1371/journal.pone.0006712.
Intracellular labels such as dextran coated superparamagnetic iron oxide nanoparticles (SPION), bromodeoxyuridine (BrdU) or green fluorescent protein (GFP) are frequently used to study the fate of transplanted cells by in vivo magnetic resonance imaging or fluorescent microscopy. Bystander uptake of labeled cells by resident tissue macrophages (TM) can confound the interpretation of the presence of intracellular labels especially during direct implantation of cells, which can result in more than 70% cell death. In this study we determined the percentages of TM that took up SPION, BrdU or GFP from labeled bone marrow stromal cells (BMSCs) that were placed into areas of angiogenesis and inflammation in a mouse model known as Matrigel plaque perfusion assay. Cells recovered from digested plaques at various time points were analyzed by fluorescence microscopy and flow cytometry. The analysis of harvested plaques revealed 5% of BrdU(+), 5-10% of GFP(+) and 5-15% of dextran(+) macrophages. The transfer of the label was not dependent on cell dose or viability. Collectively, this study suggests that care should be taken to validate donor origin of cells using an independent marker by histology and to assess transplanted cells for TM markers prior to drawing conclusions about the in vivo behavior of transplanted cells.
细胞内标记物，如葡聚糖包裹的超顺磁性氧化铁纳米颗粒（SPION）、溴脱氧尿苷（BrdU）或绿色荧光蛋白（GFP），常用于通过体内磁共振成像或荧光显微镜研究移植细胞的命运。驻留组织巨噬细胞（TM）对标记细胞的旁观者摄取可能会混淆对细胞内标记物存在的解释，特别是在直接植入细胞时，这可能导致超过 70%的细胞死亡。在这项研究中，我们确定了在称为 Matrigel 斑块灌注测定的小鼠模型中，将标记的骨髓基质细胞（BMSC）置于血管生成和炎症区域后，从标记的 BMSC 摄取 SPION、BrdU 或 GFP 的 TM 的百分比。通过荧光显微镜和流式细胞术分析在不同时间点从消化斑块中回收的细胞。对收获的斑块的分析显示 BrdU(+) 的巨噬细胞为 5%，GFP(+) 的巨噬细胞为 5-10%，葡聚糖(+) 的巨噬细胞为 5-15%。标记的转移不依赖于细胞剂量或活力。总的来说，这项研究表明，在得出关于移植细胞体内行为的结论之前，应通过组织学使用独立标记物仔细验证供体细胞的来源，并评估移植细胞的 TM 标记物，以确保准确性和可信度。
