Effect of IL-1ra on human dental pulp cells and pulpal inflammation

AIM: This study was conducted to investigate the effect of interleukin-1 receptor antagonist (IL-1ra) on the LPS-induced interleukin-1beta (IL-1beta) synthesis in human dental pulp cells and to assess the role of IL-1ra in pulpal inflammation. METHODS: IL-1beta from human dental pulp cells (HDP) was measured by sandwich ELISA; IL-1ra expression in pulpal tissue was detected by immunohistochemical staining. RESULTS: Stimulation of HDP with increasing concentrations of FnLPS resulted in dose-dependent IL-1beta production. The addition of IL-1ra reduced FnLPS-induced IL-1beta synthesis in human dental pulp cells. Significant inhibition of the FnLPS-induced IL-1beta synthesis was observed when IL-1ra was added before treating with FnLPS for 60 min. Large numbers of IL-1ra positive neutrophils, plasmacytes, endothelial cells and lymphocytes were observed in inflamed pulp tissue. CONCLUSIONS: IL-1ra could reduce LPS-stimulated IL-1beta synthesis, suggesting that IL-1ra may play a role in pulpitis.