Perfecting Achilles Tendinopathy Inducement: Preliminary Study in Animal Model - BONAR Score as Quantitative Indicator.

Background. As a common ailment suffered by runners and athletes, Achilles tendinopathy pathogenesis is not well understood. To reveal its cellular and molecular changes, universal and standardized method to induce Achilles tendinopathy in animal model (in vivo) study should be established. There are 2 major guidelines to induce Achilles tendinopathy: run the rats on treadmill without inclination and run the rats on treadmill with 10° inclination. Objective. To compare available Achilles tendinopathy induction procedure hence determining the most effective procedure. Methods. Laboratory experimental animal study (in vivo) with post-test only control group approach. 2 procedures to induce Achilles tendinopathy on Wistar rats were performed: running at 15 m/min for 180 minutes, and running at 25 m/min for 15 minutes with 10° inclination for 60 minutes. Histological changes of Achilles tendon were converted into Bonar score while several inflammatory markers such as extracellular high mobility group box-1 (HMGB-1), tumor necrosis factor-alpha (TNF-α), C-X-C motif chemokine ligand-12 (CXCL-12), and macrophage-2 (M2) were measured. Results. Highest Bonar score was obtained from rats that run at 25 m/min for 15 minutes with 10° inclination for 60 minutes. Highest level of extracellular HMGB-1, TNF-α, and CXCL-12 was also obtained from similar group. This group also showed widest M2 coverage area. Conclusions. Running the rats at 25 m/min for 15 minutes with 10° inclination for 60 minutes is more effective than running the rats at 15 m/min for 180 minutes without inclination to induce Achilles tendinopathy. [ABSTRACT FROM AUTHOR]