TRPV1 and arthritic joint disease: To examine ROS and TRPV1 interactions, two arthritis models were used in the present study including (a) in vivo inflammation of the knee joint in rats induced by injecting 3% kaolin and 3% carrageenan (k/c) directly into the knee joint injection and (b) in vitro human clonal type B synoviocytes (SW982) and primary synoviocytes harvested from clinic patients with active arthropathies [19].