Subtraction micro-computed tomography of angiogenesis and osteogenesis during bone repair using synchrotron radiation with a novel contrast agent
Subtraction micro-computed tomography of angiogenesis and osteogenesis during bone repair using synchrotron radiation with a novel contrast agent
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DOI：
10.1038/labinvest.2013.87
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发表时间：
2013-09-01
影响因子：
5
通讯作者：
Sato, Syota
中科院分区：
文献类型：
--
作者：
Matsumoto, Takeshi;Goto, Daichi;Sato, Syota
骨修复过程中血管生成的定量三维（3D）成像仍然是一个实验挑战。我们开发了一种含有0.07至0.1 μ m二氧化锆颗粒（ZrCA）的新型造影剂，并使用同步加速器辐射（sSRCT）建立了减影μ CT，用于血管生成和骨修复的定量成像。将该方法应用于钻孔损伤后3天（DAY 3; n = 2）、5天（DAY 5; n = 8）或10天（DAY 10; n = 8）的胫骨修复的大鼠模型。使用相同的钻孔缺损模型，通过比较机械卸载（n = 6）和正常负重（n = 6）10天的后肢之间的骨修复来说明其潜在用途。在用ZrCA进行血管铸造后，用17.9-和18.1-keV X射线扫描缺损部位。在后者中，由于二氧化锆在18.0 keV（k-边缘）处的急剧吸收跳跃，ZrCA填充的脉管系统和骨之间的图像对比度增强。两个扫描数据集以2.74 μ m的体素分辨率重建，通过互信息配准，并数字减影以提取对比增强的血管图像。在17.9 keV下扫描K2 HPO 4体模溶液以定量评价骨矿物质。血管生成已经开始，但在第3天未发现新骨形成。术后第5天，缺损边缘有新生骨出现，术后第10天，新生骨呈微血管浸润的小梁样结构。血管和骨体积分数、血管和骨厚度以及矿化在第10天高于第5天。所有这些参数被发现后10天的后肢卸载，减少机械刺激引起的骨修复损伤的血管生成的可能参与。总之，sSRCT和ZrCA血管铸型的组合技术适用于血管生成及其周围骨再生的定量3D成像。这种方法将有助于更好地了解血管生成和骨修复之间的联系。
Quantitative three-dimensional (3D) imaging of angiogenesis during bone repair remains an experimental challenge. We developed a novel contrast agent containing 0.07- to 0.1-mu m particles of zirconium dioxide (ZrCA) and established subtraction mu CT using synchrotron radiation (sSRCT) for quantitative imaging of angiogenesis and bone repair. This method was applied to a rat model of tibial bone repair 3 days (DAY3; n = 2), 5 days (DAY5; n = 8), or 10 days (DAY10; n = 8) after drill-hole injury. Using the same drill-hole defect model, its potential use was illustrated by comparison of bone repair between hindlimbs subjected to mechanical unloading (n = 6) and normal weight bearing (n = 6) for 10 days. Following vascular casting with ZrCA, the defect site was scanned with 17.9- and 18.1-keV X-rays. In the latter, image contrast between ZrCA-filled vasculature and bone was enhanced owing to the sharp absorption jump of zirconium dioxide at 18.0 keV (k-edge). The two scan data sets were reconstructed with 2.74-mu m voxel resolution, registered by mutual information, and digitally subtracted to extract the contrast-enhanced vascular image. K2HPO4 phantom solutions were scanned at 17.9 keV for quantitative evaluation of bone mineral. Angiogenesis had already started, but new bone formation was not found on DAY3. New bone emerged near the defect boundary on DAY5 and took the form of trabecular-like structure invaded by microvessels on DAY10. Vascular and bone volume fractions, blood vessel and bone thicknesses, and mineralization were higher on DAY10 than on DAY5. All these parameters were found to be decreased after 10 days of hindlimb unloading, indicating the possible involvement of angiogenesis in bone repair impairment caused by reduced mechanical stimuli. In conclusion, the combined technique of sSRCT and ZrCA vascular casting is suitable for quantitative 3D imaging of angiogenesis and its surrounding bone regeneration. This method will be useful for better understanding the linkage between angiogenesis and bone repair.