The effect of aging related structural changes in tendons on the development of tendinopathies and the capacity to respond to therapeutic exercise

肌腱病和肌腱损伤是临床上的主要话题，特别是在运动医学和作为老年人的疾病。这项研究利用已建立的早发性肌腱病大鼠体内模型，针对不同年龄组，确定有助于抵抗和修复疲劳损伤累积的结构、组成和生物力学蛋白质。该项目的目的是评估与疲劳损伤累积程度相关的结构和成分。为了达到这一目的，对青年和老年大鼠的膝盖腱分别施加两种不同的循环拉力，并对其生物力学性能进行测量。二次谐波成像将用于量化结构损伤的程度。在2周的愈合期后，将采集肌腱，并用免疫组织化学方法检查关键蛋白的差异。目的二是确定运动对幼年和老年动物之间相同参数的影响。疲劳负荷后2周，其中一个亚组进行体能训练，其他亚组保持笼养活跃水平。研究结果不仅将为年龄对肌腱病体育训练有效性的影响提供新的见解，还将为促进肌腱重塑的结构和成分因素提供新的见解。研究的第二部分(AIM III)将探讨超声弹性成像作为一种方法在大鼠膝腱中应用的有效性。超声弹性成像是一种非侵入性成像工具，可以实时测量软组织的弹性。在这个模型中应用超声弹性成像的能力将允许在受控动物研究中对这项技术进行更严格的评估和调查。为了验证，AIM I中的动物将在洞项目期间进行扫描，以确定超声弹性测量与诱导损伤和生物力学测量之间的相关性。声弹成像将使用当前的两种技术(应变弹性成像和共享波弹性成像)进行。为了评估超声弹性成像作为治疗指导的有效性，超声弹性成像方法也将被应用于正在进行运动的动物和康复期间活跃在笼子中的动物(AIM II中的动物)的疲劳损伤肌腱。

Tendinopathies and tendon injuries are major clinical topics, especially in sports medicine and as a disease of the elderly. The proposed study utilizes a well established in-vivo rat model of early onset tendinopathy to identify structural, compositional and biomechanical proteins that contribute to the resistance and repair of fatigue damage accumulation in consideration of different age groups.AIM I of this project will be to asses the structure and composition associated with the extent of accumulation of fatigue damage. To complete this aim, patellar tendons of young and old rats will fatigue loaded with two different protocols of cyclic tensile force and measured concerning their biomechanical properties. Second harmonic generation imaging will be used to quantify the level of structural damage. After a healing period of 2 weeks tendons will be harvested and examined for differences in key proteins using immunohistochemistry. AIM II will be to determine the effect of exercise regarding the same parameters between young and old animals. 2 weeks after fatigue loading the one subgroups will be exposed to physical training and the other subgroups will be kept on cage-active level. Results will provide new insight not only into the effect of age on effectiveness of physical training on tendinopathy, but also on the structural and compositional factors that contribute to tendon remodeling.A second part of the study (AIM III) will address the validation of sonoelastography as a method for application in rat patellar tendons. Sonoelastography is a non-invasive imaging tool that measures elasticity of soft tissue in real-time. The capacity to apply sonoelastography in this model will allow for a more rigorous assessment and investigation of this technique in controlled animal studies. For validation, animals in Aim I will be scanned during the hole project for determination of correlations between sonoelastographic measures and induced damage and biomechanical measures. Sonoelastography will be performed using two current technologies (Strain elastography and Share-wave elastography). To assess the utility of sonoelastography as a guide for therapeutics, sonoelastography methods also will be applied to fatigue damaged tendons in animals undergoing exercise and cage-active animals during the healing period (animals in Aim II).