Nanostructural and nanomechanical responses of collagen fibrils in the collagenase-induced Achilles tendinitis rat model.
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.
Department of Biomedical Engineering and Healthcare Industry Research Institute, College of Medicine, Kyung Hee University, Seoul 130-701, Korea.
Gi-Ja
GJ
Lee
Samjin
S
Choi
Jinmann
J
Chon
Seung Don
SD
Yoo
Hee-Sang
HS
Kim
Hun-Kuk
HK
Park
Joo Ho
JH
Chung
D000125:Achilles Tendon / Q000187:drug effects / Q000473:pathology* / Q000503:physiopathology*; D000818:Animals; D017364:Collagenases; D055119:Elastic Modulus; D024022:Fibrillar Collagens / Q000737:chemistry* / Q000648:ultrastructure*; D008297:Male; D040542:Mechanotransduction, Cellular; D051381:Rats; D017207:Rats, Sprague-Dawley; D052256:Tendinopathy / Q000139:chemically induced / Q000473:pathology* / Q000503:physiopathology*; D013718:Tensile Strength
D024022:Fibrillar Collagens; D017364:Collagenases