Lee Gi-Ja, Choi Samjin, Chon Jinmann, Yoo Seung Don, Kim Hee-Sang, Park Hun-Kuk, Chung Joo Ho
Department of Biomedical Engineering and Healthcare Industry Research Institute, College of Medicine, Kyung Hee University, Seoul 130-701, Korea.
J Nanosci Nanotechnol. 2013 Nov;13(11):7279-86. doi: 10.1166/jnn.2013.8092.
Achilles tendons are vulnerable to acute or chronic injuries that lead to inflammation. We investigated nanostructural and nanomechanical changes in collagen fibrils from rat Achilles tendons over a period of 9 weeks after injury using atomic force microscopy (AFM). To evaluate the nanostructural changes in Achilles tendons, we measured the diameter and D-banding of collagen fibrils by AFM. And the adhesion forces, which were related to cross-linking of collagen, were calculated from the retraction process of a force-distance curve. We successfully observed the time course of changes in collagen fibrils during healing using AFM. The diameters and D-banding in healed tendons were similar to those of uninjured tendons at 9 weeks after injury, but the adhesion forces remained different from those of uninjured tendons. Our AFM results depicted the minute changes in Achilles tendon surface by natural healing quite well, even drawbacks to naturally healed tendon. Understanding changes in collagen cross-linking and structure while healing will lead to better understanding of healing mechanisms and subsequent improvements in treatment. And AFM can be applied as powerful tool to evaluate structural and property changes in collagen fibrils before and after injury and/or treatment in Achilles tendon.
跟腱容易受到导致炎症的急性或慢性损伤。我们使用原子力显微镜（AFM）研究了大鼠跟腱损伤后9周内胶原纤维的纳米结构和纳米力学变化。为了评估跟腱的纳米结构变化，我们通过AFM测量了胶原纤维的直径和D带。并且从力-距离曲线的回缩过程计算出与胶原交联相关的粘附力。我们成功地使用AFM观察了愈合过程中胶原纤维变化的时间进程。损伤后9周时，愈合肌腱的直径和D带与未损伤肌腱相似，但粘附力仍与未损伤肌腱不同。我们的AFM结果很好地描绘了跟腱表面通过自然愈合的微小变化，甚至包括自然愈合肌腱的缺点。了解愈合过程中胶原交联和结构的变化将有助于更好地理解愈合机制以及后续治疗的改进。并且AFM可以作为一种强大的工具来评估跟腱损伤和/或治疗前后胶原纤维的结构和性质变化。
