MMP3 and fibromyalgia: Many orthopedic and joint diseases with unclear etiology are associated with excessive inflammatory responses,[12] such as osteoarthritis[13] and rheumatoid arthritis.[14] Both osteoarthritis and rheumatoid arthritis are accompanied by inflammatory responses and upregulation of MMP-3.[15,16] The pathogenesis of fibromyalgia is also closely related to inflammation.