MMP13 and exostosis: Weekly i.a. injections of parathyroid hormone PTH (1–34) for 3 months increased GAG and reduced OARSI and apoptosis rates [41], while s.c. injections of PTH (1–34) for 5 days/week for 3 or 6 months reduced the roughness, ulceration, osteophytes OARSI score, MMP13, sclerostin (SOST), and RANKL production, and increased COLL II, PTH receptor (PTH1R), osteoprotegerin (OPG), BV/TV, and SMI more than saline solution treatment [42].