Buckley Mark R, Dunkman Andrew A, Reuther Katherine E, Kumar Akash, Pathmanathan Lydia, Beason David P, Birk David E, Soslowsky Louis J
J Biomech Eng. 2013 Apr;135(4):041005. doi: 10.1115/1.4023700.
While useful models have been proposed to predict the mechanical impact of damage in tendon and other soft tissues, the applicability of these models for describing in vivo injury and age-related degeneration has not been investigated. Therefore, the objective of this study was to develop and validate a simple damage model to predict mechanical alterations in mouse patellar tendons after aging, injury, or healing. To characterize baseline properties, uninjured controls at age 150 days were cyclically loaded across three strain levels and five frequencies. For comparison, damage was induced in mature (120 day-old) mice through either injury or aging. Injured mice were sacrificed at three or six weeks after surgery, while aged mice were sacrificed at either 300 or 570 days old. Changes in mechanical properties (relative to baseline) in the three week post-injury group were assessed and used to develop an empirical damage model based on a simple damage parameter related to the equilibrium stress at a prescribed strain (6%). From the derived model, the viscoelastic properties of the 300 day-old, 570 day-old, and six week post-injury groups were accurately predicted. Across testing conditions, nearly all correlations between predicted and measured parameters were statistically significant and coefficients of determination ranged from R² = 0.25 to 0.97. Results suggest that the proposed damage model could exploit simple in vivo mechanical measurements to predict how an injured or aged tendon will respond to complex physiological loading regimens.
虽然已经提出了有用的模型来预测肌腱和其他软组织损伤的力学影响，但尚未研究这些模型在描述体内损伤和与年龄相关的退变方面的适用性。因此，本研究的目的是开发并验证一个简单的损伤模型，以预测衰老、损伤或愈合后小鼠髌腱的力学改变。为了表征基线特性，对150日龄的未受伤对照在三个应变水平和五个频率下进行循环加载。为了进行比较，通过损伤或衰老在成熟（120日龄）小鼠中诱导损伤。受伤小鼠在手术后三周或六周处死，而老年小鼠在300或570日龄处死。评估损伤后三周组力学性能（相对于基线）的变化，并用于基于与规定应变（6%）下的平衡应力相关的简单损伤参数开发一个经验损伤模型。从推导模型中，准确预测了300日龄、570日龄和损伤后六周组的粘弹性特性。在所有测试条件下，预测参数与测量参数之间几乎所有的相关性都具有统计学意义，决定系数范围为R² = 0.25至0.97。结果表明，所提出的损伤模型可以利用简单的体内力学测量来预测受伤或老化的肌腱对复杂生理负荷方案的反应。
