Abnormal extracellular matrix (ECM) remodeling was a key characteristic and pathological progress in tendinopathy, and increased COL I, COL III, MMP3 and MMP9 expression as well as decreased COL III/COL I rate and TIMP-1 content were detected in the tendinopathy mice (Fig. 4d–e). This evidence concerns the gene MMP9 and disease of the tendon.