THE INTRINSIC TENSILE BEHAVIOR OF THE MATRIX OF BOVINE ARTICULAR-CARTILAGE AND ITS VARIATION WITH AGE
THE INTRINSIC TENSILE BEHAVIOR OF THE MATRIX OF BOVINE ARTICULAR-CARTILAGE AND ITS VARIATION WITH AGE
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DOI：
10.2106/00004623-198062070-00007
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发表时间：
1980-01-01
影响因子：
5.3
通讯作者：
MOW, VC
中科院分区：
文献类型：
--
作者：
ROTH, V;MOW, VC
为了研究牛髌股关节软骨单轴拉伸行为的年龄依赖性，将216个髌股关节软骨标本分为两个年龄组：有生长板的关节（开放骺板）和无生长板的关节（无骺板）。从组织的3个超微结构区（浅表切线区、中间区和深部区）制备标准哑铃形试样。制备长轴平行或垂直于关节面局部劈裂线轴的试样。在这些拉伸试验中，在与表面以下深度相关的拉伸性能变化方面，观察到2个年龄组之间存在显著差异。随着距关节面距离的增加，开放骺板组的抗张强度和刚度增加，而无骺板组的抗张强度和刚度降低。拉伸响应的方向依赖性表现为增加的刚度和强度的平行于分裂线轴取向的样品相比，垂直于它的样品取向。变形的最初平坦，直边部分的计量部分观察到在大多数的216个标本后立即施加拉伸应变。先前横截面尺寸变化的测量可能不准确。显然，这种变形的发生是因为关节软骨是一种不均匀的分层材料。当施加的拉伸应变变大时，软骨渗出大量的间质液。这两个影响造成严重的问题，在评估真正的体积变化和材料特性的软骨标本在单轴拉伸实验。未成熟关节软骨（开放骺板组）的胶原蛋白可能具有独特的生物物理特性和独特的结构。与成熟组织相比，未成熟组织在张力方面的上级机械响应是这些生物物理性质和超微结构的表现。成熟后，有一个下降的拉伸强度性能的中间和深层区域，但不是在那些浅切线区的组织。成熟后，关节软骨的表面层的作用可能是重要的，在关节功能期间保护组织免受不利的机械应力。该表面层完整性的任何破坏，例如，由早期骨关节病的纤维性颤动引起的疼痛将使组织的生物力学下部暴露于大的拉伸应力和应变，这可能导致正常关节功能的最终丧失。
To study the age dependence of the uniaxial tensile behavior of bovine articular cartilage, 216 specimens of articular cartilage from the patellofemoral joint were grouped into 2 age categories: those from joints with growth plates present (open physes) and those from joints without growth plates (no physes). Standard, dumbbell-shaped test specimens were prepared from the 3 ultrastructural zones of the tissue: the superficial tangential zone, the middle zone and the deep zone. Specimens were prepared whose long axes were parallel or perpendicular to the axis of the local split line on the joint surface. In these tensile tests a profound difference was observed between the 2 age groups in terms of the variations in the tensile properties related to the depth below the surface. With increasing distance from the articular surface, the tensile strength and stiffness increased in the open-physis group and decreased in the no-physis group. Directional dependence of the tensile response was manifested by increased stiffness and strength of the samples oriented parallel to the split-line axis compared to the samples oriented perpendicular to it. Distortion of the initially flat, straight-sided portion of the gauge section was observed in most of the 216 specimens immediately after the application of tensile strains. Previous measurements of cross-sectional dimensional changes may be inaccurate. Apparently, this distortion occurs because articular cartilage is an inhomogeneous, layered material. Cartilage exuded substantial amounts of its interstitial fluid when the applied tensile strain becomes large. These 2 effects create serious problems in assessing the true volumetric changes and the material properties of cartilage specimens during uniaxial tension experiments. The collagen of immature articular cartilage (open-physis group) may have unique biophysical properties and a unique architecture. The superior mechanical response in tension of immature compared to mature tissue is a manifestation of these biophysical properties and of the ultrastructure. After maturation, there is a decrease in the tensile-strength properties of the middle and deep zones but not in those of the superficial tangential zone of the tissue. After maturation, the role of the surface layer of articular cartilage may be important in protecting the tissue from unfavorable mechanical stresses during joint function. Any disruptions of the integrity of this surface layer, e.g., those caused by the fibrillation of early osteoarthrosis, will expose the biomechanically inferior portions of the tissue to large tensile stresses and strains, which could lead to ultimate loss of normal joint function.