Arokoski J P, Hyttinen M M, Helminen H J, Jurvelin J S
Department of Physical and Rehabilitation Medicine, Kuopio University Hospital, Finland.
J Biomed Mater Res. 1999;48(2):99-107. doi: 10.1002/(sici)1097-4636(1999)48:2<99::aid-jbm1>3.0.co;2-n.
To analyze the interrelationships between the structure, composition, and mechanical properties of articular cartilage, canine knee (n = 10) femoral and tibial cartilages were used as experimental tissues. The biomechanical properties, instant shear modulus (IM), and equilibrium shear modulus (EM) of articular cartilage were investigated using an in situ indentation creep technique. The local variations in the concentration of glycosaminoglycans (GAGs) in the cartilage were measured with a microspectrophotometer after safranin-O staining of histological sections. Using a computer-based quantitative polarized light microscopy method, area-specific measurements of the optical path difference were performed to quantitate collagen-related optical retardation (gamma) of cartilage zones. The IM and EM were 131.3 and 51.2% higher (p < 0.001) in the femoral cartilage than in the tibial cartilage, respectively. The mean thickness of the superficial zone and the relative proportion of the superficial zone from the total uncalcified cartilage was 107.1 and 155.3% higher (p < 0.001) at the femoral test points than in the tibial ones, respectively. The mean thickness of the tibial uncalcified cartilage was 21.1% higher (p < 0.001) than the thickness of the femoral cartilage. The GAG concentration of the tibial cartilage was higher (14.8%, p < 0.001) than that of the femoral cartilage, especially in the superficial zone (50.0%, p < 0.05), whereas the gamma of the collagen network in the superficial zone of the femoral cartilage was 64.7% higher (p < 0.001) than in the tibial cartilage. The percent relative thickness and retardation gamma of the superficial zone correlated positively with the indentation stiffness of the canine knee articular cartilage. These observations indicate that cartilage is structurally inhomogenous and layered tissue and the local organization of collagen and GAG concentration of the articular cartilage regulate the biomechanical properties of the tissue. The structure and composition of the superficial articular cartilage significantly affects the indentation response of the canine knee articular cartilage.
为分析关节软骨的结构、组成和力学性能之间的相互关系，采用犬膝关节（n = 10）的股骨和胫骨软骨作为实验组织。使用原位压痕蠕变技术研究关节软骨的生物力学性能、瞬时剪切模量（IM）和平衡剪切模量（EM）。在组织学切片经番红O染色后，用显微分光光度计测量软骨中糖胺聚糖（GAGs）浓度的局部变化。使用基于计算机的定量偏振光显微镜方法，对光程差进行区域特异性测量，以定量软骨区域中与胶原蛋白相关的光学延迟（γ）。股骨软骨的IM和EM分别比胫骨软骨高131.3%和51.2%（p < 0.001）。股骨测试点处浅层区域的平均厚度和浅层区域占总未钙化软骨的相对比例分别比胫骨测试点高107.1%和155.3%（p < 0.001）。胫骨未钙化软骨的平均厚度比股骨软骨厚21.1%（p < 0.001）。胫骨软骨的GAG浓度高于股骨软骨（14.8%，p < 0.001），尤其是在浅层区域（50.0%，p < 0.05），而股骨软骨浅层区域胶原蛋白网络的γ比胫骨软骨高64.7%（p < 0.001）。浅层区域的相对厚度百分比和延迟γ与犬膝关节软骨的压痕硬度呈正相关。这些观察结果表明，软骨是结构不均匀的分层组织，关节软骨中胶原蛋白和GAG浓度的局部组织调节了组织的生物力学性能。关节软骨浅层的结构和组成显著影响犬膝关节软骨的压痕反应。
