Expression of Pain Receptors by Arthritis Treatment in Collagen Induced Murine Model of Rheumatoid Arthritis

Objective. Rheumatoid arthritis, the most common form of arthritis, is typically characterized by induced inflammatory pain in joints. Recent studies have reported on the expression of pain receptors such as transient receptor potential vanilloid 1 (TRPV1) and acid sensing ion channel 3 (ASIC3), which are related to pain induction and regulation. This study was conducted to investigate the expression of TRPV1 and ASIC3 in response to the analgesic effect of an arthritis treatment in a collagen-in-duced arthritis (CIA). Methods. Mice were divided into 3 groups: Control, CIA, and CIA with arthritis treatment. Mice received intraperitoneal injection with 10 mg/kg infliximab and 10 mg/kg meloxicam five times per week for 3 weeks. Mechanical hyper-algesia, histologic examination of the feet, serum levels of inflammatory cytokine such as interleukin-6 (IL-6), and interleukin-17 (IL-17), TRPV1 and ASIC3 expression were investigated. Results. The serum levels of IL-6 and IL-17 were lower in the treatment group (73.77±10.11 pg/mL and 26.75±7.17 pg/mL, respectively) compared to the CIA group (p＜0.001). Histological analysis showed decreased synovial cell proliferation, leukocyte infiltration, and cartilage destruction in the treatment group compare