Origins of Elasticity/Viscoelasticity in Knee Ligaments

描述（由申请人提供）：膝关节韧带是一条坚韧的纤维结缔组织短带，可引导正常关节运动并限制异常关节运动。虽然膝关节韧带的损伤和愈合一直是广泛研究的主题，但关于组织的超微结构与其连续水平力学行为之间关系的基本信息严重缺乏。核心蛋白聚糖在胶原纤维形成中起重要作用，可能是结缔组织材料行为的重要决定因素。本研究的目的是探讨核心蛋白聚糖交联和流体流动在弹性和粘弹性材料行为韧带中的作用。要解决的假设是1）基于核心蛋白聚糖的交联通过在胶原原纤维的相对运动期间拉伸来控制韧带对横向于纤维方向的拉伸载荷和沿着纤维方向的剪切载荷的抵抗力;（二）横向各向同性超弹性本构模型，其结合了关于核心蛋白聚糖交联和胶原纤维卷曲的结构信息，将描述和预测人类膝关节韧带; 3）韧带的粘弹性材料行为是由于流体运动。这些假设将通过一系列的目标，结合联合收割机实验测量从分子水平的连续水平。这项研究的结果将有重要的意义，了解的基本作用的小蛋白聚糖和流体流动的粘弹性行为的纤维结缔组织，并将有助于了解与疾病状态相关的表型，是在小蛋白聚糖的缺陷。

DESCRIPTION (provided by applicant): The knee ligaments are short bands of tough fibrous connective tissue that guide normal joint motion and restrict abnormal joint movement. Although the injury and healing of knee ligaments have been topics of extensive study, fundamental information about the relationship between the ultrastructure of the tissue and its continuum level mechanical behavior is severely lacking. The decorin-based proteoglycans play an important role in collagen fibrillogenesis and may be important determinants of the material behavior of connective tissues. The objectives of this research are to investigate the roles of decorin-based proteoglycan crosslinks and fluid flow in the elastic and viscoelastic material behavior ligaments. The hypotheses to be addressed are 1) decorin-based crosslinks control the resistance of ligament to tensile loading transverse to the fiber direction and shear loading along the fiber direction by stretching during relative movement of the collagen fibrils; 2) a transversely isotropic hyperelastic constitutive model that incorporates structural information regarding decorin crosslinks and collagen fiber crimp will describe and predict the elastic material behavior of human knee ligaments; 3) The viscoelastic material behavior of ligament is due to fluid movement. These hypotheses will be addressed through a series of aims that combine experimental measurements from the molecular level to the continuum level. The results of this study will have important implications for understanding the fundamental role of the small proteoglycans and fluid flow in the viscoelastic behavior of fibrous connective tissues, and will help to understand the phenotypes associated with disease states that are related to deficiencies in the small proteoglycans.