The effect of IL-1 receptor antagonist on orthodontic tooth movement in mice.

OBJECTIVE Orthodontic tooth movement (OTM) is achieved by alveolar bone remodelling induced by mechanical loading. Whilst interleukin-1 (IL-1) is directly involved in OTM, the role of interleukin-1 receptor antagonist (IL-1Ra), a naturally occurring IL-1 antagonist, is not completely defined. Therefore, the aim of this study was to investigate the effects of IL-1Ra on OTM. METHODS An orthodontic appliance was placed in C57BL6 mice treated with vehicle or IL-1Ra (10 mg/kg/day). OTM and TRAP-positive osteoclasts were evaluated after 12 days of mechanical loading and the levels of cytokines on periodontal tissues were analysed by ELISA after 12 and 72 h. RESULTS Mice treated with IL-1Ra showed diminished OTM and decreased numbers of TRAP-positive osteoclasts. In line with this, lower levels of IL-1β and TNF-α, and higher levels of IL-10, were observed on periodontal tissues of IL-1Ra-treated mice in relation to the vehicle-treated group. CONCLUSION The present study suggests that IL-1Ra downregulates OTM, probably by its anti-inflammatory actions.