Cartilage Fracture Toughness By Micropenetration

描述（由申请人提供）： 本研究的目的是发展微穿透的方法来测量小鼠和较大物种的软骨的断裂韧性，然后使用该方法在骨关节炎（OA）小鼠模型中检验关于OA病因的假设。 在前期工作中开发的理论和实验方法将被完善，并用于预测穿透深度和断裂韧性在牛软骨。为了验证该方法，将预测的深度与组织学测量的深度进行比较;将预测的断裂韧性与使用独立宏观方法测量的断裂韧性进行比较。预测的断裂韧性的敏感性，材料性能的变化，然后将进行评估牛软骨消化与胶原酶。一个大变形，粘弹性有限元模型先前开发的将被扩展，以帮助理解的过程中，并提供一种替代方法的数据减少。在牛软骨上开发该方法后，该程序将转移到小鼠软骨上。为了验证，将再次将小鼠中的预测穿透深度与通过组织学测量的穿透深度进行比较。 在小鼠中完成方法的开发后，它们将用于测量STR/ort小鼠（一种发生早发OA的品系）和CBA小鼠（一种不发生早发OA的品系）在不同年龄的断裂韧性。将使用小鼠软骨的组织学和SEM来评估纤维性颤动。数据将用于检验在自然发生OA的动物模型中软骨弱化先于纤维化的假设。

DESCRIPTION (provided by applicant): The goal of this research is to develop the method of micropenetration to measure the fracture toughness of cartilage in mice and larger species, and then use the method to test a hypothesis on the etiology of osteoarthritis (OA) in a mouse model of OA. Theoretical and experimental methods developed in preliminary work will be refined and used to predict depth of penetration and fracture toughness in bovine cartilage. To validate the method, predicted depth will be compared to that measured by histology; the predicted fracture toughness will be compared with fracture toughness measured using an independent macroscopic method. The sensitivity of predicted fracture toughness to changes in material properties will then be assessed on bovine cartilage subjected to digestion with collagenase. A large deformation, viscoelastic finite element model previously developed will be extended to aid in understanding the process and provide an alternative method for data reduction. After developing the method on I bovine cartilage, the procedures will be transferred to mouse cartilage. For validation, predicted depth of penetration in the mouse will again be compared with that measured by histology. After completing development of the methods in mice, they will be used to measure the fracture toughness in STR/ort mice, a strain that develops premature OA, and CBA mice, a strain that does not develop premature OA, at various ages. Histology and SEM of the mouse cartilage will be used Ito evaluate fibrillation. Data will be used to test the hypothesis that cartilage weakening precedes fibrillation in an animal model of naturally occurring OA.