Effect of soluble receptors to interleukin-1 and tumor necrosis factor alpha on experimentally induced root resorption in rats

OBJECTIVE: In this study, the role of the inflammatory cytokines interleukin-1 (IL-1) and tumor necrosis factor alpha (TNFalpha) in the course of mechanically induced root resorption was investigated. METHODS: Mechanical induction of root resorption was performed on the upper left first molars in 18 male Wistar rats according to the method of Nakane and Kameyama. Starting on day minus 1, six animals received daily intraperitoneal injections of 2 ml of 1 micro g/ml soluble receptors to IL-1 (sIL-1RII) and another six animals were administered the same dose of soluble receptors to TNFalpha (sTNFalpha-RI). Six animals served as a control. On d 7 the left maxillae were prepared for histological and morphometric analysis of the extent of the root resorption that had developed. RESULTS: The qualitative and quantitative results demonstrated that in both receptor groups the amount of root resorption was significantly reduced. Especially following systemic application of sTNFalpha-RI, root resorption was nearly completely prevented. CONCLUSIONS: Our results indicate that IL-1 and more particularly TNFalpha are important for the induction and the further process of mechanically induced root resorption in the rat.