Effects of tribological stimulation on chondrocyte metabolism and development of functional cartilage tissue structure for joint lubrication

关节软骨是一种独特而有趣的软组织，因为它覆盖了关节的关节面，并发挥着重要的作用，作为“轴承”，以实现顺利的关节运动。然而，在这方面，软骨表面复杂的摩擦学功能的建立过程的详细机制尚未阐明，本研究项目的目的是通过软骨细胞对关节运动过程中所经历的机械载荷的代谢反应来研究关节润滑的功能性软骨组织结构的发育过程。软骨组织可以感知施加到组织上的机械应力和应变。软骨细胞随后通过机械传导途径调节其代谢并维持功能性软骨组织结构。本文研制了一种滚动滑动摩擦加载机， ...更多信息 H可以实验性地再现在关节接合期间通过摩擦力施加在软骨表面上的摩擦学刺激，例如压缩应变、剪切应变和流体剪切。将加载装置安装在CO_2培养箱中，对琼脂糖凝胶内三维培养的软骨细胞施加摩擦刺激，观察摩擦刺激对软骨细胞合成细胞外基质和组织结构发育的影响。然后，通过Pyrex玻璃辊在2小时内将纯滑动施加到试样表面，每天两次，持续5天。结果表明，通过施加纯滑动，释放到培养基中的糖胺聚糖（GAG）的量增加。此外，在加载样本的最上部区域内积累了大量GAG。这些结果可能表明，纯滑动负荷上调细胞外基质的生物合成的最高区域的培养标本，并可能阐述了蛋白多糖丰富的层，已被确定在天然关节软骨的表面区域，并将发挥重要的作用，在关节润滑。此外，培养的软骨细胞-琼脂糖标本内的材料运输的特性进行了实验评估，以了解支架材料对培养的软骨细胞的营养供应和标本内的细胞外基质分子的扩散的影响。在摩擦试验中还检测了蛋白质分子的润滑能力，以估计天然和再生软骨组织的边界润滑机制。少

Articular cartilage is one of the unique and interesting soft tissues since it covers articulating surfaces of diarthrodial joints and plays an important role as "bearing" to achieve smooth joint movements. However, the detailed mechanism which governs the establishing process of the sophisticated tribological functions on the cartilage surface has not been clarified yet The purpose of this research project has been to investigate the developing process of functional cartilage tissue structure for the joint lubrication by the metabolic response of chondrocytes to the mechanical loadings experienced during the joint movement.It is well recognized that chondrocytes embedded in cartilage tissue can sense the mechanical stress and strain applied to the tissue. The chondrocytes subsequently regulate their metabolism through the mechanotransduction pathways and maintain the functional cartilage tissue structure. In this study, we have developed a rolling-sliding friction loading machine whic … More h can experimentally reproduce tribological stimulations, such as compressive strain, shear strain and fluid shear, exerted on the cartilage surface by frictional force during joint articulation. The loading machine was installed in CO_2 incubator and used to apply the tribological stimulation to chondrocytes being cultured three dimensionally within agarose gel Then, the effects of the tribological stimulations on the biosynthesis of extracellular matrix by chondrocytes and development of tissue structure were examined.Chondrocytes-agarose specimens were first culture under static condition for three days. Then, pure sliding was applied to the specimen surfaces by Pyrex glass rollers during 2 hours, twice a day for 5 days. Results indicated that the amount of glycosaminoglycan (GAG) released to the culture medium was increased by applying the pure sliding. Moreover, significant amount of GAG was accumulated within the uppermost region of the loaded specimens. These results might be indicating that the loading of pure sliding up-regulated the biosynthesis of extracellular matrix within the uppermost region of cultured specimens and might elaborate the proteoglycan-rich layer which had been identified within the surface region of natural articular cartilage and would be playing the important role in the joint lubrication. In addition, characteristics of the material transport within the cultured chondrocytes-agarose specimen was evaluated experimentally to understand the effect of scaffold materials on the nutrient supply to cultured chondrocytes and the diffusion of extracellular matrix molecules within the specimens. The lubrication ability of protein molecules was also examined in the friction test to estimate the boundary lubrication mechanism of natural and re-generated cartilage tissue. Less