Experimental investigation of collagen waviness and orientation in the arterial adventitia using confocal laser scanning microscopy
Experimental investigation of collagen waviness and orientation in the arterial adventitia using confocal laser scanning microscopy
复制标题
DOI：
10.1007/s10237-011-0325-z
复制
发表时间：
2012-03-01
影响因子：
3.5
通讯作者：
Stergiopulos, N.
中科院分区：
文献类型：
--
作者：
Rezakhaniha, R.;Agianniotis, A.;Stergiopulos, N.
外膜的机械性能很大程度上取决于胶原纤维的组织。测量胶原蛋白的波纹度和取向，特别是在零应力状态下，对于将胶原蛋白的结构组织与外膜的机械响应联系起来是必要的。使用荧光胶原蛋白标记物 CNA38-OG488 和共焦激光扫描显微镜，我们对兔颈总动脉外膜中的胶原纤维进行离体成像。沿着动脉的纵轴切开动脉以获得零应力状态。我们使用半手动和自动技术来测量与纤维的波纹度和取向相关的参数。我们的结果表明，直线度参数（定义为纤维端点距离与其长度之比）呈 beta 分布（平均值 0.72，方差 0.028），并且不依赖于纤维的平均角度方向。局部角密度分布揭示了四个轴对称纤维族，相对于动脉的轴向方向，平均方向为0A度、90A度、43A度和-43A度，相应的圆形标准偏差为40A度、47A度、37A度和37A度。与零应力状态（切开）的动脉相比，在零负载状态（完整）的动脉中测量时，局部方向的分布转移到圆周方向。本研究中获得的有关胶原纤维波纹度和取向的信息可用于开发外膜的结构模型，为分析和理解血管壁的机械特性提供更好的方法。
Mechanical properties of the adventitia are largely determined by the organization of collagen fibers. Measurements on the waviness and orientation of collagen, particularly at the zero-stress state, are necessary to relate the structural organization of collagen to the mechanical response of the adventitia. Using the fluorescence collagen marker CNA38-OG488 and confocal laser scanning microscopy, we imaged collagen fibers in the adventitia of rabbit common carotid arteries ex vivo. The arteries were cut open along their longitudinal axes to get the zero-stress state. We used semi-manual and automatic techniques to measure parameters related to the waviness and orientation of fibers. Our results showed that the straightness parameter (defined as the ratio between the distances of endpoints of a fiber to its length) was distributed with a beta distribution (mean value 0.72, variance 0.028) and did not depend on the mean angle orientation of fibers. Local angular density distributions revealed four axially symmetric families of fibers with mean directions of 0A degrees, 90A degrees, 43A degrees and -43A degrees, with respect to the axial direction of the artery, and corresponding circular standard deviations of 40A degrees, 47A degrees, 37A degrees and 37A degrees. The distribution of local orientations was shifted to the circumferential direction when measured in arteries at the zero-load state (intact), as compared to arteries at the zero-stress state (cut-open). Information on collagen fiber waviness and orientation, such as obtained in this study, could be used to develop structural models of the adventitia, providing better means for analyzing and understanding the mechanical properties of vascular wall.