Table III.

Evidence of the effects of melatonin on osteoarthritis in animal studies.

Refs.	Objectives	Model	Route of administration	Time of administration	Frequency	Doses	Duration	Outcomes
82	C57BL/6J mice	Surgically-induced osteoarthritis	Intra-articular injection	After surgery	Twice a week	10 mg/ml (10 µl)	4 weeks	Attenuated OA progression
87	New Zealand white rabbits (female)	Surgically-induced osteoarthritis	Intra-articular injection	Beginning on the day of surgery	Weekly	20 mg/kg	4 weeks	Reduced cartilage degradation
88	Lewis rats	Surgically-induced osteoarthritis	Intra-articular injection	On day 3 following the surgery	Once	10 mg/ml (20 µl)	-	Repressed expression of relevant genes in rat OA pathogenesis after 3 weeks
95	Sprague-Dawley rats	Intra-articular collagenase injection- induced osteoarthritis	Subcutaneous injection	-	Twice daily	10 mg/kg	4 weeks	Melatonin prevented periarticular muscle damage and cartilage degeneration. But prolonged melatonin administration leaded to subchondral bone erosion
112	Sprague Dawley rats	Intra-articular collagenase injection- induced osteoarthritis	Subcutaneous injection	07:00 and 19:00	Twice daily	10 mg/kg	1, 4 weeks	Melatonin with treadmill exercise may have both preventive and synergistic effects on rescue from cartilage degeneration and is more effective in the initial phase (1 week)