Voiland School of Chemical Engineering and Bioengineering, Washington State University, PO Box 646515, Pullman, WA, 99164, USA.
Department of Biological Sciences, University of Idaho, 875 Perimeter Drive, MS 3051, Moscow, ID, 83844, USA.
Sci Rep. 2019 Jun 3;9(1):8196. doi: 10.1038/s41598-019-44671-9.
Tendons must be able to withstand the forces generated by muscles and not fail. Accordingly, a previous comparative analysis across species has shown that tendon strength (i.e., failure stress) increases for larger species. In addition, the elastic modulus increases proportionally to the strength, demonstrating that the two properties co-vary. However, some species may need specially adapted tendons to support high performance motor activities, such as sprinting and jumping. Our objective was to determine if the tendons of kangaroo rats (k-rat), small bipedal animals that can jump as high as ten times their hip height, are an exception to the linear relationship between elastic modulus and strength. We measured and compared the material properties of tendons from k-rat ankle extensor muscles to those of similarly sized white rats. The elastic moduli of k-rat and rat tendons were not different, but k-rat tendon failure stresses were much larger than the rat values (nearly 2 times larger), as were toughness (over 2.5 times larger) and ultimate strain (over 1.5 times longer). These results support the hypothesis that the tendons from k-rats are specially adapted for high motor performance, and k-rat tendon could be a novel model for improving tissue engineered tendon replacements.
肌腱必须能够承受肌肉产生的力量而不失效。因此，之前对不同物种的比较分析表明，肌腱强度（即失效应力）随着物种的增大而增加。此外，弹性模量与强度成正比增加，表明这两个特性是共同变化的。然而，一些物种可能需要特别适应的肌腱来支持高绩效的运动活动，如短跑和跳跃。我们的目的是确定袋鼠鼠（k-rat）的肌腱是否是弹性模量和强度之间线性关系的例外，袋鼠鼠是一种可以跳跃到自身臀部高度十倍的小型双足动物。我们测量并比较了 k-rat 踝关节伸肌肌腱和同样大小的白鼠肌腱的材料特性。k-rat 和大鼠肌腱的弹性模量没有差异，但 k-rat 肌腱的失效应力比大鼠值大得多（几乎大 2 倍），韧性（大 2.5 倍以上）和极限应变（大 1.5 倍以上）也是如此。这些结果支持了这样一种假设，即 k-rat 的肌腱是专门为高运动表现而适应的，k-rat 肌腱可能是一种改善组织工程肌腱替代物的新型模型。
