Authors: S. Choi, G.-J. Lee, J. Chon, S.-J. Chae, S.-D. Yoo, J.-H. Park, K.-S. Kim, H.-K. Park
Affilation: Kyung Hee University, Korea
Pages: 478 - 481
Keywords: extracorporeal shockwave therapy, nanoscale structure, property, Achilles tendons, collagen fibrils, Atomic force microscopy
Extracorporeal shockwave therapy (ESWT) is popular in the treatment of musculo-skeletal injuries. However, the mechanism by which such therapy might have an effect on tendon injury is unknown. The Achilles tendons are mainly composed of Type I collagen fibers including collagen fibrils. Therefore, the aim of this study was to observe the effects of ESWT in healing process of the rat collagenase-induced Achilles tendonitis (CIAT) model. Seventeen male Sprague-Dawley rats were used. An induction of CIAT model was elicited by an injection of 30 μl crude collagenase into the bone-tendon junction of both hindpaws. Fifteen CIAT rats were sacrificed properly at 2d-63d after collagenase injection. 7d-33d rats were treated by ESWT. Atomic force microscopy (AFM) imaging and adhesion force was measured using the non-contact and contact mode. Ultrastructure and property changes in the Achilles tendon with and without ESWT application were evaluated by diameter and D-banding of collagen fibrils, and adhesion force. In CIAT rats, fibril diameter and adhesion force showed significant maximum increases (p<0.0001) at 40d after. Interestingly, the collagen fibril diameter and adhesion force in CIAT rats with ESWT application showed the maximum increases (p<0.0001) at 12d after injection. Further, the pattern of change in two parameters during period (7d-26d) with ESWT was similar to that of post-period (33d-63d) without ESWT. We suggest that ESWT might have the effect in reducing the healing period in the Achilles tendonitis.