Institute of Sports Medicine Copenhagen, Bispebjerg Hospital and Center for Healthy Aging, University of Copenhagen, Denmark.
Connect Tissue Res. 2011 Oct;52(5):415-21. doi: 10.3109/03008207.2010.551569. Epub 2011 Mar 31.
Correct mechanical function of tendons is essential to human physiology and therefore the mechanical properties of tendon have been a subject of research for many decades now. However, one of the most fundamental questions remains unanswered: How is load transmitted through the tendon? It has been suggested that the proteoglycan-associated glycosaminoglycans (GAGs) found on the surface of the collagen fibrils may be an important transmitter of load, but existing results are ambiguous and have not investigated human tendons. We have used a small-scale mechanical testing system to measure the mechanical properties of fascicles from human patellar tendon at two different deformation rates before and after removal of GAGs by treatment with chondroitinase ABC. Efficiency of enzyme treatment was quantified using dimethylmethylene blue assay. Removal of at least 79% of the GAGs did not significantly change the tendon modulus, relative energy dissipation, peak stress, or peak strain. The effect of deformation rate was not modulated by the treatment either, indicating no effect on viscosity. These results suggest that GAGs cannot be considered mediators of tensile force transmission in the human patellar tendon, and as such, force transmission must either take place through other matrix components or the fibrils must be mechanically continuous at least to the tested length of 7 mm.
肌腱的正确机械功能对于人体生理学至关重要，因此，肌腱的机械性能一直是数十年来研究的课题。然而，有一个最基本的问题仍然没有答案：负荷是如何通过肌腱传递的？有人认为，在胶原纤维表面发现的与蛋白聚糖相关的糖胺聚糖（GAGs）可能是负荷的重要传递者，但现有结果并不明确，并且尚未研究人类肌腱。我们使用小规模机械测试系统，在使用软骨素酶 ABC 去除 GAGs 前后，分别以两种不同的变形率测量了人类髌腱束的机械性能。使用二甲亚甲基蓝测定法定量测定酶处理的效率。去除至少 79%的 GAGs 不会显著改变肌腱的模量、相对能量耗散、峰值应力或峰值应变。处理也没有调制变形率的影响，表明对粘性没有影响。这些结果表明，GAGs 不能被认为是人类髌腱中拉伸力传递的介质，因此，力传递必须通过其他基质成分进行，或者纤维必须至少在测试长度为 7mm 的情况下保持机械连续性。
