In-situ characterization of the uncrimping process of arterial collagen fibers using two-photon confocal microscopy and digital image correlation.
In-situ characterization of the uncrimping process of arterial collagen fibers using two-photon confocal microscopy and digital image correlation.
复制标题
使用两光子共聚焦显微镜和数字图像相关性，对动脉胶原纤维的非冰箱过程的原位表征。
DOI：
10.1016/j.jbiomech.2013.08.001
复制
发表时间：
2013-10-18
影响因子：
2.4
通讯作者：
Gleason RL Jr
中科院分区：
文献类型：
--
作者：
Wang R;Brewster LP;Gleason RL Jr
动脉壁中胶原纤维的解卷曲是调节动脉的宏观水平机械响应的整体过程。胶原纤维的解卷曲导致动脉在生理压力下逐渐但显著的应变硬化反应，并防止在升高的压力下过度扩张。在这项研究中，我们成像外膜胶原纤维从一个新鲜的灵长类动物动脉使用双光子激发显微镜，而动脉生理膨胀压力和轴向拉伸。通过在动脉充盈时调整焦距，将成像焦平面固定在外膜壁中的恒定径向位置，从而连续监测单个胶原纤维区域的解卷曲过程。然后将数字图像相关性应用于序列图像，以评估局部位移并将其与所选参考纤维及其接合的手动迹线相关联。我们发现，感兴趣的胶原纤维在20 mmHg的管腔压力下完全接合，然后随着大动脉继续扩张，这些纤维显著旋转。该技术允许开发解卷曲指标，以更准确地表征生理负荷下胶原纤维的运动学，这可以帮助开发更准确的动脉微结构本构模型。
Uncrimping of collagen fibers in the arterial wall is an integral process in modulating the macro-level mechanical response of arteries. Uncrimping of collagen fibers leads to a gradual, but significant strain-stiffening response of the artery at physiological pressures and prevents overdistention at elevated pressures. In this study, we imaged adventitial collagen fibers from a fresh primate artery using two-photon excitation microscopy while subjecting the artery to physiological inflation pressures and axial stretch. The imaging focal plane was fixed at a constant radial location in the adventitial wall by adjusting the focal distance as the artery inflated, allowing for the continuously monitoring of the uncrimping process of a single region of collagen fibers. Digital image correlation was then applied to the sequential images to assess and correlate the local displacements to manual traces of selected reference fibers and their engagements. We found that the collagen fibers of interest became fully engaged at a luminal pressure of 20 mmHg, this was then followed by significant rotation of these fibers as the bulk artery continued to dilate. This technique allows for the development of uncrimping metrics to more accurately characterize the kinematics of collagen fibers under physiological loads, which can aid in the development of more accurate microstructural constitutive models for arteries.