The preventive effect of melatonin and/or exercise on cartilage destruction in collagenase‐induced osteoarthritis rats

Abstract

Osteoarthritis (OA) is the major cause of disability in the adult population. HIF‐2a is a crucial catabolic regulator of arthritic cartilage destruction. The purpose of this study is to evaluate the prophylactic effect of melatonin and/or exercise on the degenerative change in cartilage of collagenase‐induced OA rats. Melatonin (MT) was injected twice/day subcutaneously. The treadmill exercise (Ex) was conducted for 1‐hr/day(5 days/week). The width of affected knee joints was reduced by co‐intervention at day 28 after collagenase injection (P<.05). MT+Ex reduced EPAS1 as well as MMP13, whereas it increased ADAMTS4 level at day 28 (P<.05). There were ill‐defined cell layer, abnormally condensed cell morphology, and cartilage surface erosion in the OA+Veh group. However, it was reorganized in the OA+MT+Ex group. Not only bone surface density(BS/BV) but also trabecular number(Th.N) was significantly increased in OA+Veh as well as OA+MT group. However, it was recovered to normal level in OA+MT+Ex group. Taken together, melatonin with treadmill exercise effectively inhibits the initiation of OA induction suggesting prophylactic effect on degenerative OA progression.