Hansen Philip, Hassenkam Tue, Svensson Rene Bruggebusch, Aagaard Per, Trappe Todd, Haraldsson Bjarki Thor, Kjaer Michael, Magnusson Peter
Institute of Sports Medicine Copenhagen, Bispebjerg Hospital & Centre for Healthy Aging, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.
Connect Tissue Res. 2009;50(4):211-22. doi: 10.1080/03008200802610040.
Conclusive insight into the microscopic principles that govern the strength of tendon and related connective tissues is lacking and the importance of collagen cross-linking has not been firmly established. The combined application of whole-tissue mechanical testing and atomic force spectroscopy allowed for a detailed characterization of the effect of cross-linking in rat-tail tendon. The cross-link inducing agent glutaraldehyde augmented the tensile strength of tendon fascicles. Stress at failure increased from approximately 8 MPa to approximately 39 MPa. The mechanical effects of glutaraldehyde at the tendon fibril level were examined by atomic force microscopy. Peak forces increased from approximately 1379 to approximately 2622 pN while an extended Hertz fit of force-indentation data showed a approximately 24 fold increase in Young's modulus on indentation. The effect of glutaraldehyde cross-linking on the tensile properties of a single collagen fibril was investigated by a novel methodology based on atomic force spectroscopy. The Young's modulus of a secluded fibril increased from approximately 407 MPa to approximately 1.1 GPa with glutaraldehyde treatment. Collectively, the findings indicate that cross-linking at the level of the collagen fibril is of key importance for the mechanical strength of tendon tissue. However, when comparing the effects at the level of the tendon fascicle and fibril, respectively, further questions are prompted regarding the pathways of force through the tendon microstructure as fibril strength seems to surpass that of the tendon fascicle.
目前仍缺乏对决定肌腱及相关结缔组织强度的微观原理的确切认识，胶原蛋白交联的重要性也尚未得到确凿证实。全组织力学测试与原子力光谱学的联合应用，使得对大鼠尾腱交联作用的详细表征成为可能。交联诱导剂戊二醛增强了肌腱束的拉伸强度。破坏应力从约8兆帕增加到约39兆帕。通过原子力显微镜研究了戊二醛在肌腱原纤维水平的力学效应。峰值力从约1379皮牛增加到约2622皮牛，同时力-压痕数据的扩展赫兹拟合显示，压痕时杨氏模量增加了约24倍。通过一种基于原子力光谱学的新方法，研究了戊二醛交联对单根胶原原纤维拉伸性能的影响。经戊二醛处理后，孤立原纤维的杨氏模量从约407兆帕增加到约1.1吉帕。总体而言，这些发现表明，胶原原纤维水平的交联对于肌腱组织的机械强度至关重要。然而，在分别比较肌腱束和原纤维水平的效应时，由于原纤维强度似乎超过肌腱束，关于力通过肌腱微观结构的途径引发了进一步的问题。
