Moderate Exercise Protects Against Joint Disease in a Murine Model of Osteoarthritis

Exercise is recommended as a non-pharmacological therapy for osteoarthritis (OA). Clinical studies investigating the impact of exercise on OA have primarily focussed on the assessment of joint pain and mobilisation, where positive outcomes have been demonstrated. Clinical imaging studies provide limited information on the impact of exercise (positive or negative) on the actual bone and soft tissue pathology. Various exercise regimes, with differing intensities and duration, have been used in a range of OA models, with disparate results. The present study provides definitive insight into the effect of moderate exercise on early joint pathology in the destabilisation of the medial meniscus (DMM) mouse model of OA. Exercise was induced by forced treadmill walking for 3 or 7 weeks. Joints were analysed by microcomputed tomography and histology. Exercise offered protection against cartilage damage and joint inflammation, and a temporary protection against osteosclerosis. Furthermore, exercise modified the metaphyseal trabecular microarchitecture of the osteoarthritic leg. Collectively, our findings provide scientific support for the clinical recommendation of moderate exercise as a physical therapy in OA. In addition to indirect benefit via positive physiological effects of weight loss, our data suggest direct short-term benefits in ameliorating pathology of cartilage, synovitis and bone.