Three-Dimensional Distribution of Transverse Collagen Fibers in the Anterior Human Corneal Stroma
Three-Dimensional Distribution of Transverse Collagen Fibers in the Anterior Human Corneal Stroma
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DOI：
10.1167/iovs.13-13150
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发表时间：
2013-11-01
影响因子：
4.4
通讯作者：
Jester, James V.
中科院分区：
文献类型：
--
作者：
Winkler, Moritz;Shoa, Golroxan;Jester, James V.
目的。最近对人类角膜结构和生物力学的研究表明，基质胶原纤维（片层）被组织成一个复杂的、高度交织的横向定向纤维三维网络，增加基质刚度并控制角膜形状。本研究的目的是利用一种自动化的方法来表征胶原纤维沿角膜主要经络的横向三维分布，以快速量化胶原纤维的角度取向。三位捐赠者的三只眼睛在压力下进行灌注固定，切除并切成四个象限。使用振动体对象限进行物理切片，并使用非线性光学高分辨率宏观显微镜进行扫描。使用软件对平面进行数值分析，以确定胶原纤维相对于角膜表面的角度、基质深度和基质前250 μ m内的径向位置。纤维角度的范围和相对于角膜表面的角位移大于+/- 3.5度的纤维百分比（“横向纤维”）在前基质中最高，随着深度的增加而减少。数值分析显示，在象限、子午线和径向位置之间，纤维角度和横向纤维无显著差异。这些结果与我们之前观察到的角膜中央基质胶原相互连接的深度依赖性梯度相吻合，并表明这种梯度从角膜中央延伸到角膜缘。缺乏相对于角膜象限或径向位置的倾斜纤维的优选分布可能有助于均匀分布载荷并避免应力集中区域的形成。
PURPOSE. Recent investigations of human corneal structure and biomechanics have shown that stromal collagen fibers (lamellae) are organized into a complex, highly intertwined three-dimensional meshwork of transverse oriented fibers that increases stromal stiffness and controls corneal shape. The purpose of this study was to characterize the three-dimensional distribution of transverse collagen fibers along the major meridians of the cornea using an automated method to rapidly quantify the collagen fibers' angular orientation.METHODS. Three eyes from three donors were perfusion-fixed under pressure, excised, and cut into four quadrants. Quadrants were physically sectioned using a vibratome and scanned using nonlinear optical high-resolution macroscopy. Planes were analyzed numerically using software to identify collagen fiber angles relative to the corneal surface, stromal depth, and radial position within the anterior 250 mu m of the stroma.RESULTS. The range of fiber angles and the fiber percentage having an angular displacement greater than +/- 3.5 degrees relative to the corneal surface ("transverse fibers'') was highest in the anterior stroma and decreased with depth. Numerical analysis showed no significant differences in fiber angles and transverse fibers between quadrants, meridians, and radial position.CONCLUSIONS. These results match our previous observation of a depth-dependent gradient in stromal collagen interconnectivity in the central cornea, and show that this gradient extends from the central cornea to the limbus. The lack of a preferred distribution of angled fibers with regard to corneal quadrant or radial position likely serves to evenly distribute loads and to avoid the formation of areas of stress concentration.