骨性关节炎动物模型内侧副韧带的应力松弛

背景：韧带和其他生物软组织一样，具有黏弹性特性，其应力松弛和蠕变黏弹性特性是为适应人的生理功能需要而存在的。研究说明骨性关节炎对韧带力学性能具有一定影响。 目的：比较正常和骨性关节炎动物模型内侧副韧带的应力松弛流变特性，确定骨性关节炎对内侧副韧带应力松弛特性的影响。 方法：以闭合关节刻痕法复制骨性关节炎动物模型，取正常和骨性关节炎动物模型大鼠膝关节内侧副韧带各10个试样，进行应力松弛实验。应力松弛实验的应变增加速度为5%/s。设定实验时间为7 200 s，采集100个数据，观察应力松弛数据和曲线、应力与时间的变化规律，以一元线性回归分析的方法处理实验数据。 结果与结论：正常组和病态组试样应力松弛最初600 s变化较快，之后应力缓慢下降，正常组7 200 s应力松弛量0.47 MPa，病态组7 200 s应力松弛量0.29 MPa。模型组7 200 s应力松弛量显著低于正常组(P < 0.05)，且应力松弛曲线是以对数关系变化的。说明骨性关节炎时可以使膝关节对内侧副韧带应力松弛量降低，对膝关节应力松弛特性具有一定影响。

Stress relaxation of medial collateral ligament in an animal model of osteoarthritis

BACKGROUND:Similar to other soft tissues, ligament has viscoelasticity. The stress relaxation and creep viscoelasticity of ligaments are based on human physiologic functions. Studies have demonstrated that osteoarthritis has effect on ligament mechanical property. OBJECTIVE: To compare stress relaxation rheological properties of medial collateral ligament (MCL) between normal and osteoarthritis animal models, to determine the influence of osteoarthritis on MCL ligament stress relaxation characteristics. METHODS:Animal osteoarthritis models were prepared by closed joint Nick method. Each 10 MCL samples were taken from normal and osteoarthritis rats for stress relaxation experiments. The strain increase rate was 5%/s, and test duration was 7 200 s, a total of 100 data were collected. The stress relaxation data, and change laws of curves, stress and time were observed. All data were analyzed by one linear regression. RESULTS AND CONCLUSION:The stress relaxation of the normal and model groups changed fast at the initial 600 s, followed by a slow decrease. The stress relaxation of the normal group at 7 200 s was 4.69 MPa, and the model group was 0.29 MPa. The 7 200 s stress relaxation quantity of the model group was obviously smaller than that of the normal group (P < 0.05). The stress relaxation curves were changed in a log relationship. The knee osteoarthritis can decrease MCL stress relaxation, which influences LCL stress relaxation characteristics.