Subcutaneous Injections of a TNF-α Antagonistic Peptide Inhibit Both Inflammation and Bone Resorption in Collagen-Induced Murine Arthritis

Abstract

The cyclic peptide WP9QY (YCWSQYLCY), which was designed to mimic the most critical tumor necrosis factor (TNF) Ï recognition loop on type1 TNF receptor, antagonizes the effects of TNFÏ. In this study, we investigated the effects of WP9QY peptide on collagen- induced arthritis (CIA) mice to evaluate its effects on inflammatory bone destruction. DBA/1J mice were injected intradermally at the base of the tail with bovine type II collagen, emulsified in complete Freund’s adjuvant on day 0 and 21. The three sets of WP9QY peptide injections (24 mg/kg×8 times per day) were performed before the onset of paw swelling. Mice were sacrificed at day 38 and thereafter, the arthritis scores as well as radiographical and histological outcomes were assessed. WP9QY peptide inhibited CIA- induced increase in the arthritis score. Furthermore, histomorphometric analysis of the tibial epiphysis region revealed that WP9QY peptide inhibited the increase of synovial pannus infiltration and the decrease of bone volume, which were induced by the CIA. The WP9QY treatment prevented the inflammation as well as bone destruction of the joints in the CIA mice, suggesting that the administration of WP9QY peptide might be useful for developing a drug to prevent inflammatory bone destruction.