Project 434785

Arthritis pain is a serious clinical issue in Canada. Its relief is often unsatisfactory, and it is often increased by movement. Our understanding of its mechanisms is poor, which makes developing more efficacious therapies difficult. There are two major arthritis subtypes, osteoarthritis and inflammatory arthritis, depending on whether joint damage or inflammation prevail. However, they have something in common: the level of degeneration and inflammation seen does not correlate with the pain experienced. These disconnects between pain and inflammation, or degeneration, suggest other factors contribute to arthritis pain. We strongly believe that this disconnect is caused by a component in arthritis pain which is neuropathic-like, i.e. like pain following nerve damage, but this is still poorly characterized. In this grant, we will characterize the neuropathic-like pain component in both osteoarthritis and inflammatory arthritis and assess how it is influenced by movement (forced walking). Our research will be done in both male and female rats, to account for possible sex differences in pain mechanisms. We will use pain-related behaviour testing, drugs and anatomical tools to investigate: a) what peripheral and central changes drive this hypersensitivity in freely moving rats after induction of inflammatory arthritis or osteoarthritis; and b) investigate how drug treatments affect these changes. This project will 1) give a better understanding of the mechanisms underlying arthritis pain, 2) identify appropriate targets for the treatment of arthritis pain.