The arterial wall consists of three concentric layers: intima, media, and adventitia. Beyond their resident cells, these layers are characterized by an extracellular matrix (ECM), which provides both biochemical and mechanical support. Elastin, the major component of arterial ECM, is present in the medial layer and organized in concentric elastic lamellae that confer resilience to the wall. We explored the arterial wall structures from C57Bl6 (control), db/db (diabetic), and ApoE^−/− (atherogenic) mice aged 3 months using synchrotron X-ray computed microtomography on fixed and unstained tissues with a large image field (8 mm³). This approach combined a good resolution (0.83 µm/voxel), large 3D imaging field. and an excellent signal to noise ratio conferred by phase-contrast imaging. We determined from 2D virtual slices that the thickness of intramural ECM structures was comparable between strains but automated image analysis of the 3D arterial volumes revealed a lattice-like network within concentric elastic lamellae. We hypothesize that this network could play a role in arterial mechanics. This work demonstrates that phase-contrast synchrotron X-ray computed microtomography is a powerful technique which to characterize unstained soft tissues.

中文翻译：

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X 射线显微断层扫描显示主动脉弹性薄片内的格状网络

动脉壁由三个同心层组成：内膜、中膜和外膜。除了它们的常驻细胞外，这些层的特征是细胞外基质 (ECM)，它提供生化和机械支持。弹性蛋白是动脉 ECM 的主要成分，存在于中间层并组织成同心弹性薄片，赋予血管壁弹性。我们使用同步加速器 X 射线计算机显微断层扫描技术对具有大图像视野的固定和未染色组织进行了 3 个月大的C57Bl6（对照）、db / db（糖尿病）和ApoE ^-/-（致动脉粥样硬化）小鼠的动脉壁结构（8毫米³）。这种方法结合了良好的分辨率（0.83 µm/体素）和大的 3D 成像场。以及相衬成像赋予的出色信噪比。我们从 2D 虚拟切片确定壁内 ECM 结构的厚度在应变之间是可比的，但 3D 动脉体积的自动图像分析显示同心弹性薄片内的格状网络。我们假设这个网络可以在动脉力学中发挥作用。这项工作表明，相衬同步加速器 X 射线计算机显微断层扫描是一种表征未染色软组织的强大技术。