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

a b s t r a c t 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 TRAPpositive osteoclasts. In line with this, lower levels of IL-1b and TNF-a, and higher levels of IL10, were observed on periodontal tissues of IL-1Ra-treated mice in relation to the vehicletreated group. Conclusion: The present study suggests that IL-1Ra downregulates OTM, probably by its antiinflammatory actions.