Elucidation of Adaptive Multimode Lubrication Mechanism and Self-Organization in Natural Synovial Joints

本研究的目的是从层次和微观的角度阐明自然滑膜关节的适应性多模式润滑机制与自组织的关系。在模拟器上对膝关节模型中的流体膜形成进行了实验评价和数值分析，表明了弹流润滑在行走过程中的重要作用。在摆法猪肩关节摩擦试验中，通过去除吸附膜或添加磷脂或蛋白质，阐明了透明质酸浓度对高、低载荷条件下摩擦行为的影响。由磷脂、蛋白质和糖蛋白组成的吸附膜的边界润滑明显表现为去除吸附膜后摩擦力的增加。添加磷脂脂质体和γ-球蛋白是有效的…更多的是在降低摩擦方面。利用原子力显微镜(AFM)观察了摩擦过程中不同摩擦水平下关节软骨表面的变化。分析了不同摩擦水平下相应的力-距离曲线。这些结果表明，随着磨损过程的进行，吸附膜和凝胶膜的润滑作用发生了变化。比较了聚乙烯醇(PVA)水凝胶作为人工软骨和天然关节软骨的摩擦学性能，以阐明两者的差异。采用基于有限元的三维数值分析方法，研究了压缩刺激对关节软骨细胞的影响。用激光共聚焦扫描显微镜(CLSM)观察关节软骨细胞的形态和分布，建立三维模型。结果表明，压缩加载后即刻，地表附近的局部应变大于平均值，并恢复到平均值。这种局部高应变有可能对位于这些区域的软骨细胞产生显着影响。用激光共聚焦显微镜观察应变的变化。较少

The object of this research is to elucidate the adaptive multimode lubrication mechanism in natural synovial joints in relation to the self-organization from the hierarchic and microscopic viewpoints.The systematic investigation was performed to clarify the adaptive multimode lubrication mechanism in natural synovial joints. Experimental evaluation of fluid film formation in knee joint model in simulator and numerical analysis showed the important role of elastohydrodynamic lubrication during walking. In friction tests of pig shoulder joints by pendulum method, the influence of hyaluronate concentration on frictional behavior under high and low load conditions was clarified in related to removal of adsorbed films or addition of phospholipid or proteins. The boundary lubrication by adsorbed film composed of phospholipids, proteins and glycoproteins was clearly shown by an increase in friction after removal of adsorbed film. Addition of phospholipid liposome and γ-globulin was effective … More in lowering of friction. The atomic force microscopy (AFM) was applied to observe the changes in articular cartilage surfaces at different friction levels during rubbing process. The corresponding force-distance curves at several friction levels were examined. These results indicated that lubricating roles of adsorbed film and gel film change with progressive wear process. The tribological property of polyvinyl-alcohol (PVA) hydrogel specimen as artificial cartilage was compared with that of natural articular cartilage to clarify the difference between both materials. The three-dimensional numerical analysis based on finite element method was conducted to examine the influence of compressive stimulation on chondrocyte in articular cartilage. The morphology and distribution of chondrocytes in articular cartilage were investigated by confocal laser scanning microscopy (CLSM) to construct the three-dimensional model. It was noticed that the local strain near surface had larger value than average one immediately after compressive loading and recovered to the average level. This local high strain has the possibility to have a remarkable effect on the chondrocyte located in those zones. The changes in strain were observed by CLSM. Less