In situ imaging of OA cartilage micro-fluidics

描述（由申请人提供）：骨关节炎（OA）是一种使人衰弱的疾病，其中关节软骨受损，其机械功能（即负荷支撑和润滑）（取决于组织的双相行为）逐渐受损。软骨的流体相是其最丰富的成分，不仅充当减震器和承重器（由于流体相和固体相之间的粘弹耦合），而且还影响软骨营养/代谢和软骨细胞机械传导。这种流体环境的改变与OA有关。虽然建模和灌注研究已经提供了有价值的洞察软骨的流体行为，仍然是一个未满足的需要，实时原位测量软骨中的流体流动。在这项研究中，我们提出了一种新的生物成像方法来测量软骨微流体环境的时空图像相关光谱（STICS）的基础上。STICS是一种新近发展起来的成像技术，已成功地应用于细胞内溶质/蛋白质动力学的体外研究。本研究的目的是开发和标准化的STICS成像，用于原位测量机械加载软骨中的基质变形和溶质对流。一个双色共聚焦STICS方法将被用来量化的固体基质和流体相行为的空间和加载速率的依赖性在牛软骨塞进行无侧限压缩应力松弛测试。然后，我们将扩展双色STICS传输成像的定量溶质对流在人类OA软骨标本从全膝关节置换术患者。其中，我们假设，OA的负荷诱导的流体速度增加与组织损伤相关，并指示早期软骨退变。鉴于软骨的流体环境对组织功能的重要影响，建议对软骨的流体环境进行原位定量，这代表了研究软骨流体的创新工具 坚实的互动。如果成功，STICS将成为第一种直接实时定量软骨微流体和局部固体基质变形的生物成像方法，这两者都是软骨细胞功能的有效调节剂。采用新型双色STICS方法的拟议研究将产生正常和患病软骨中流体行为的新定量知识，使未来对软骨生物力学，生物学以及OA启动和进展机制的研究成为可能。

DESCRIPTION (provided by applicant): Osteoarthritis (OA) is a debilitating condition in which articular cartilage is damaged and its mechanical functions (i.e. load support and lubrication), which are dependent on the biphasic behaviors of the tissue, are progressively compromised. Cartilage's fluid phase, its most abundant component, not only acts as a shock absorber and load bearer (due to the viscoelastic coupling between the fluid and solid phases), but also influences cartilage nutrition/metabolism and chondrocyte mechanotransduction. Alterations in this fluid environment have been implicated in OA. While modeling and perfusion studies have provided valuable insight into cartilage's fluid behaviors, there remains an unmet need for real-time in situ measurement of fluid flow in cartilage. In this grant we propose a novel bioimaging approach to measure the cartilage micro-fluidic environment based upon spatiotemporal image correlation spectroscopy (STICS). STICS is a recently developed imaging technique that has been successfully applied to the study of intracellular solute/protein kinetics in vitro. The objective of this study is to develop and standardized STICS imaging for the in situ measurement of both matrix deformation and solute convection in mechanically loaded cartilage. A dual-color confocal STICS approach will be used to quantify the spatial and loading rate dependency of solid matrix and fluid phase behaviors in bovine cartilage plugs subjected to unconfined compression stress-relaxation tests. We will then extend dual-color STICS transport imaging to the quantification of solute convection in human OA cartilage specimens obtained from total knee arthroplasty patients. In which, we hypothesize that load-induced fluid velocity increases with OA is correlated with tissue damage, and indicative of early cartilage degeneration. The proposed in situ quantification of cartilage's fluid environment, given its critical influence on tissue function, represents an innovative tool for studying cartilage's fluid solid interactions. If successful, STICS will be the first bioimaging approach for the direct real-time quantification of cartilage microfluidics and local solid matrix deformations, which are both potent modulators of chondrocyte function. The proposed studies with the novel dual-color STICS approach will yield new quantitative knowledge of the fluid behavior in both normal and diseased cartilage, enabling future investigations of cartilage biomechanics, biology, and the mechanisms of OA initiation and progression.