Biotribology of Diarthrodial Joints

关节生物摩擦学

• 批准号: 6915173
• 负责人: GERARD A. ATESHIAN
• 金额: $ 27.34万
• 依托单位: COLUMBIA UNIV NEW YORK MORNINGSIDE
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-06-15 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6915173
• 关键词: animal tissue; articular cartilage; atomic force microscopy; biomechanics; confocal scanning microscopy; fluorescence microscopy; gamma globulin; hyaluronate; joints; mechanical pressure; mechanical stress; phospholipids; protein degradation; serum albumin; surface property; synovial fluid

DESCRIPTION (provided by applicant): The primary function of articular cartilage is to serve as a bearing material for diarthrodial joints. As part of our recent studies, we have demonstrated from theory and experiments that cartilage can provide efficient lubrication even under boundary friction, primarily because its interstitial water may pressurize considerably under loading. In this application, we propose to follow-up on these findings by addressing specific questions related to the functional effectiveness of the lubrication mechanism in diarthrodial joints: a) Since the friction coefficient is observed to increase over time to functionally detrimental values under laboratory testing conditions, what makes it stay sufficiently low under physiological loading conditions in situ? b) How effective are the boundary lubricants in synovial fluid, after accounting for the role of interstitial fluid load support? c) Is there a functionally significant mixed lubrication regime in the initial response to joint loading during which lubricant is temporarily trapped between articular surfaces, and if so, does the duration of this mixed regime depend on the type of lubricant? While it may be attractive from the clinical and commercial perspective to consider joint lubrication in terms of a phenomenon arising from synovial fluid and its constituents (e.g., intra-articular injection of hyaluronan and other "lubricants"), their relative contribution to the low frictional properties of articular cartilage are not well understood. With an original theoretical framework, validated using novel experimental techniques developed over the past two granting periods that clearly describe how articular cartilage is able to exhibit extremely low friction coefficients even in the absence of synovial fluid, we now propose studies to determine the contribution of boundary lubricants in synovial fluid to the functional effectiveness of the lubrication mechanism in diarthrodial joints. Our proposal is timely in light of the recent resurgence of interest in proteins in synovial fluid or in the superficial zone of articular cartilage that may assist in the tribological response. To investigate our hypotheses, the proposal incorporates some novel applications of Atomic Force Microscopy (AFM), Total Internal Reflectance Fluorescence (TIRF) microscopy, and Scanning Confocal Microscopy (SCM) techniques.

描述（由申请人提供）：关节软骨的主要功能是作为腹膜关节的轴承材料。作为我们最近研究的一部分，我们从理论和实验中证明了软骨即使在边界摩擦下也可以提供有效的润滑，这主要是因为其间隙水在负载下可能会大大压力。在此应用中，我们建议通过解决与腹膜关节中润滑机制功能有效性有关的特定问题来跟进这些发现：a）由于观察到摩擦系数随着时间的推移增加到实验室测试条件下的功能有害值，因此在物理载荷条件下的功能降低，在实验室测试条件下保持了足够的损失？ b）考虑间质流体负荷支持的作用后，边界润滑剂在滑液中的有效性如何？ c）在对关节载荷的初始响应中，是否存在功能上显着的混合润滑状态，在关节载荷中暂时将润滑剂捕获在关节表面之间，如果是的，则该混合状态的持续时间是否取决于润滑剂的类型？从临床和商业角度来看，从滑液及其成分引起的现象（例如，关节内注射透明质酸和其他“润滑剂”）对关节润滑可能具有吸引力，但它们的相对贡献对关怀特性的相对贡献尚未得到理解。 With an original theoretical framework, validated using novel experimental techniques developed over the past two granting periods that clearly describe how articular cartilage is able to exhibit extremely low friction coefficients even in the absence of synovial fluid, we now propose studies to determine the contribution of boundary lubricants in synovial fluid to the functional effectiveness of the lubrication mechanism in diarthrodial joints.鉴于最近对滑液中蛋白质的兴趣或关节软骨的表面区域的重新出现，我们的建议及时是有助于摩擦学反应的。为了研究我们的假设，该提案结合了原子力显微镜（AFM），总内反射率荧光（TIRF）显微镜和扫描共聚焦显微镜（SCM）技术的一些新颖应用。