In Vivo Optical Imaging of Cellular Inflammatory Response in Granuloma Formation Using Fluorescence-Labeled Macrophages
In Vivo Optical Imaging of Cellular Inflammatory Response in Granuloma Formation Using Fluorescence-Labeled Macrophages
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DOI：
10.2967/jnumed.108.060707
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发表时间：
2009-10-01
影响因子：
9.3
通讯作者：
Wall, Alexander
中科院分区：
文献类型：
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作者：
Eisenblaetter, Michel;Ehrchen, Jan;Wall, Alexander
近红外成像，如荧光反射成像（FRI）和荧光介导断层扫描（FMT）产生高信噪比（SNR），因此应该非常适合细胞跟踪研究。单核细胞或巨噬细胞（M phi s）的外渗是炎症中最早的事件之一。本研究的目的是评估是否FRI和FMT允许可视化和量化的早期炎症过程中，通过跟踪迁移的荧光标记的小鼠M φ s在皮肤肉芽肿模型。方法：用膜选择性碳菁染料（1，1-双十八烷基-3，3，3，3-四甲基吲哚三碳菁碘化物[DiR]）标记M phi。在体外评估细胞活力和功能（一氧化氮产生、吞噬作用、粘附）。通过皮下注射聚丙烯酰胺凝胶颗粒（包括或不包括强烈的炎症刺激物（脂多糖））在小鼠中诱导局部炎症。静脉注射标记的M phi s，进行FRI和FMT，直至7 d。计算颗粒的SNR，并使用FMT评估M phi s的三维分布。从凝胶沉淀收获细胞并通过流式细胞术分析。结果：DiR标记不影响细胞活力或细胞功能。FRI显示标记的Mfs迁移到凝胶颗粒和M φ s归巢到不同的身体隔室。含脂多糖的颗粒比不含脂多糖的颗粒表现出显著更高的SNR。FMT结果显示，M phi s主要分布在颗粒的周边。从收获的沉淀物中提取的细胞浸润物显示存在约10%-23%的DiR阳性M phi s表达的典型标志物，证实了注射的M phi s的跨内皮迁移。结论：用DiR标记Mfs可以在体内无创追踪炎症细胞数天。FRI和FMT是监测和定量体内细胞炎症反应的通用技术。
Near-infrared imaging such as fluorescence reflectance imaging (FRI) and fluorescence-mediated tomography (FMT) yields high signal-to-noise ratios (SNRs) and should thus be well suited for cell-tracking studies. Extravasation of monocytes or macrophages (M phi s) is one of the earliest events in inflammation. The purpose of this study was to assess whether FRI and FMT allow for the visualization and quantification of early inflammatory processes by tracing the migration of fluorescence-labeled murine M phi s in a cutaneous granuloma model. Methods: M phi s were labeled with a membrane-selective carbocyanine dye (1,1-dioctadecyl-3,3,3,3- tetramethylindotricarbocyanine iodide [DiR]). Cellular viability and function (nitric oxide production, phagocytosis, adherence) were assessed in vitro. Local inflammation was induced in mice by the subcutaneous injection of polyacrylamide gel pellets including or excluding a strong inflammatory stimulus (lipopolysaccharide). Labeled M phi s were injected intravenously, and FRI and FMT were performed up to 7 d. SNRs were calculated for the pellets, and the 3- dimensional distribution of M phi s was assessed using FMT. Cells were harvested from gel pellets and analyzed by flow cytometry. Results: DiR labeling did not affect cell viability or cell function. FRI revealed the migration of labeled Mfs into gel pellets and the homing of M phi s to different body compartments. The lipopoly-saccharide-containing pellets exhibited significantly higher SNRs than did pellets without lipopolysaccharide. FMT showed that M phi s distributed mainly in the periphery of the pellets. The cellular infiltrates extracted from the harvested pellets revealed the presence of approximately 10%-23% DiR-positive M phi s-expressing typical markers, confirming the transendothelial migration of injected M phi s. Conclusion: The tagging of Mfs with DiR allows the noninvasive tracking of inflammatory cells for several days in vivo. FRI and FMT are versatile techniques to monitor and quantify cellular inflammatory responses in vivo.