Experimental Characterization of Adventitial Collagen Fiber Kinematics Using Second-Harmonic Generation Imaging Microscopy: Similarities and Differences Across Arteries, Species and Testing Conditions
Experimental Characterization of Adventitial Collagen Fiber Kinematics Using Second-Harmonic Generation Imaging Microscopy: Similarities and Differences Across Arteries, Species and Testing Conditions
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DOI：
10.1007/978-3-030-20182-1_5
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发表时间：
2020-01-01
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影响因子：
--
通讯作者：
Morin, Claire
中科院分区：
文献类型：
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作者：
Cavinato, Cristina;Badel, Pierre;Morin, Claire
众所周知，纤维胶原网络在软结缔组织对施加的载荷的被动生物力学响应中起着核心作用。在本章中，我们将重点介绍血管组织，并分享我们在耦合机械载荷和多光子成像方面的丰富经验，以研究跨动脉、物种和测试条件的胶原纤维如何响应机械载荷而移动。更具体地说，我们评估的变形胶原蛋白网络在兔，猪或人的动脉在不同的负载情况下：单轴拉伸扁平样品，拉伸膨胀管状样品，膨胀扁平样品。我们总是观察到胶原纤维在无载荷条件下表现出波浪形或卷曲形状，并且在施加载荷时倾向于解卷曲，依次接合以成为主要的承载组分。这种顺序接合是造成非线性力学行为的原因，对于动脉正常发挥功能至关重要，对于老年人和动脉瘤患者的动脉似乎不太明显。虽然胶原纤维的解卷曲是一种普遍的机制，但我们也观察到拉伸载荷特定的大纤维旋转，并沿载荷轴沿着显著重新排列。提出了一种统一的方法来比较观察和定量分析的图像处理的类型可能会显着影响胶原纤维变形的估计。总之，本章对动脉微结构及其变形对整体力学响应的基本作用进行了重要的回顾。最后，结合机械负荷和多光子成像的未来研究方向提出了建议，目的是解决与组织适应和破裂有关的开放性问题。
Fibrous collagen networks are well known to play a central role in the passive biomechanical response of soft connective tissues to applied loads. In the current chapter we focus on vascular tissues and share our extensive experience in coupling mechanical loading and multi-photon imaging to investigate, across arteries, species and testing conditions, how collagen fibers move in response to mechanical loading. More specifically, we assess the deformations of collagen networks in rabbit, porcine or human arteries under different loading scenarios: uniaxial tension on flat samples, tension-inflation on tubular samples, bulge inflation on flat samples. We always observe that collagen fibers exhibit a wavy or crimped shape in load-free conditions, and tend to uncrimp when loads are applied, engaging sequentially to become the main load-bearing component. This sequential engagement, which is responsible for the nonlinear mechanical behaviour, is essential for an artery to function normally and appears to be less pronounced for arteries in elderly and aneurysmal patients. Although uncrimping of collagen fibers is a universal mechanism, we also observe large fiber rotations specific to tensile loading, with significant realignment along the loading axis. A unified approach is proposed to compare observations and quantitative analyses as the type of image processing may affect significantly the estimation of collagen fiber deformations. In summary, this chapter makes an important review of the basic roles of arterial microstructure and its deformations on the global mechanical response. Eventually, directions for future studies combining mechanical loading and multi-photon imaging are suggested, with the aim of addressing open questions related to tissue adaptation and rupture.