PROTEOGLYCAN STRUCTURE, METABOLISM AND ROLE IN TENDON

这个项目的长期目标是了解结构， 一类细胞外基质的代谢、调节及其作用 肌腱中的组成成分--蛋白多糖。肌腱通常只包含 少量的小蛋白多糖粘附素。然而，一只蜗牛- 在牛深屈肌腱通过的地方形成丰富的纤维软骨 在骨骼下，在原位经历压缩和拉伸。在……里面 体外实验支持这样的假设，即机械负荷导致 增加大蛋白多糖的合成和积累，产生 具有特定需要的附加压缩硬度的组织 机械环境。建议进行实验，以研究长时间的 肌腱细胞对施加力的长期和短期反应 比机械载荷。(1)将建造一个新的设备以加载 体外正常拉伸的胎牛肌腱的离散区 一段时间内的应力、法向压应力或剪应力 从几分钟到几天不等。不同载荷作用下的影响 环境对蛋白多糖合成量和类型的影响，其 结构和周转，以及对mRNA的表达和定位 几种基质成分，将被测定。合成与活化 将测量作为加载结果的转化生长因子-β的含量。(2)共焦 显微镜将被用来可视化细胞对 组织负荷，如(Ca++)的变化或组织的改变 细胞骨架。酪氨酸磷酸化或酪氨酸的活性 磷酸酶将在不同的负荷方案后进行评估。(3) 细胞外基质组织和特定基质成分的作用 在调节中，细胞对组织负荷的反应将被确定 利用酶改变基质完整性和药物改变细胞骨架 组织。这一综合实验计划将首次， 允许将不同的测量机械载荷与相关的 一个组织中的细胞反应。纤维软骨提供压缩 刚性和滑动面的精确位置 属性对肌腱很有用。不适当的发展 纤维软骨导致与重复运动相关的病理 症状、愈合特性改变和风湿病。这些研究 这一提议将增加对组织水平反应的理解 使软结缔组织能够适当地调节其 组合以适应不断变化的机械环境。

The long-term goal of this project is to understand the structure, metabolism, regulation, and roles of one category of extracellular matrix constituent in tendon - the proteoglycans. Tendon generally contains only a small amount of the small proteoglycan decorin. However, an aggrecan- rich fibrocartilage develops where the bovine deep flexor tendon passes under bone and experiences compression as well as tension in situ. In vitro experiments support the hypothesis that mechanical loading leads to increased synthesis and accumulation of large proteoglycans, generating a tissue with the added compressive stiffness needed for its particular mechanical environment. Experiments are proposed to investigate the long- term and short-term responses of cells in tendon to the imposition of specific mechanical loads . (1) A new device will be constructed to load discrete regions of a fetal bovine tendon in vitro with normal tensile stress, normal compressive stress, or shear stress, for time periods ranging from minutes to days. The effects of different loading environments on the amount and type of proteoglycan synthesized, its structure and turnover, as well as on mRNA expression and localization for several matrix constituents, will be determined. Synthesis and activation of TGF-Beta as a result of loading will be measured. (2) Confocal microscopy will be used to visualize immediate cellular responses to tissue loading, such as changes in (Ca++] or altered organization of the cytoskeleton. The activity of tyrosine phosphorylation or tyrosine phosphatase will be assessed after different loading regimens. (3) The role of extracellular matrix organization and specific matrix components in regulation the cellular response to tissue loading will be determined using enzymes to alter matrix integrity and drugs to alter cytoskeletal organization. This integrated experimental plan will, for the first time, allow correlation of distinct measured mechanical loads with relevant cellular responses in one tissue. Fibrocartilage provides compressive stiffness and a gliding surface in precisely the location where such properties are useful to the tendon. The inappropriate development of fibrocartilage leads to pathology associated with repetitive motion syndromes, altered healing properties, and rheumatic disease. The studies of this proposal will increase understanding of tissue-level responses that allow soft connective tissues to appropriately modulate their composition to meet a changing mechanical environment.