In situ imaging of OA cartilage micro-fluidics

描述（由申请人提供）：骨关节炎（OA）是一种衰弱性疾病，其中关节软骨受损，其机械功能（即负载支持和润滑）依赖于组织的双相行为，逐渐受损。软骨的流体相是其最丰富的成分，不仅具有减震器和承载量（由于流体和固相之间的粘弹性耦合），而且还影响软骨的营养/代谢和软骨细胞的机械转导。这种流体环境的改变与OA有关。虽然建模和灌注研究为软骨的流体行为提供了有价值的见解，但软骨中流体流动的实时原位测量仍然是一个未满足的需求。在这项拨款中，我们提出了一种基于时空图像相关光谱（tics）的新型生物成像方法来测量软骨微流体环境。STICS是最近发展起来的一种成像技术，已经成功地应用于体外细胞内溶质/蛋白质动力学的研究。本研究的目的是开发和标准化用于原位测量机械加载软骨中基质变形和溶质对流的STICS成像。双色共聚焦的方法将用于量化的空间和加载率依赖于固体基质和流体相行为的牛软骨塞受到无侧限压缩应力松弛试验。然后，我们将扩展双色传输成像，以量化从全膝关节置换术患者获得的人类OA软骨标本的溶质对流。在这项研究中，我们假设负荷引起的骨性关节炎的流速增加与组织损伤有关，并表明早期软骨退变。鉴于软骨流体环境对组织功能的重要影响，提出了软骨流体环境的原位定量，这是研究软骨流体的一种创新工具

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.