Molecular Events of Chronic Pain: From Neuron to Whole Animal in an Animal Model of Osteoarthritis

A novel animal model of osteoarthritis has been established for studies on the disease process as well as on mechanisms underlying the symptoms of osteoarthritis, principally pain and fatigue. The model is established by cutting the anterior cruciate ligament in the rat to introduce instability of the joint, removing the medial meniscus to induce further derangement of the joint, and exercising the rat on a modified rota-rod to generate weight-bearing mobility of the joint; this exercise can be regulated in terms of duration to govern severity of the model. The model exhibits many of the characteristics of osteoarthritis in humans, including bone and cartilage remodelling, infiltration of the joint tissues by immune cells and alterations in sensory mechanisms. This model will find application in development of novel interventions for the treatment of osteoarthritis and its symptoms as well as development of diagnostic tools for early detection.