OBJECTIVETo investigate the influence of high mobility group box 1 (HMGB1) on the expression of interleukin 6 (IL-6), receptor activator of nuclear factor-kappa B ligand (RANKL) and osteoprotegerin (OPG) on periodontal ligament fibroblasts.

METHODSHuman periodontal ligament fibroblasts were stimulated with HMGB1 at concentrations of 10, 30, and 100 ng x mL(-1) for 24 h. RT-PCR and Western blot analysis were performed to check mRNA and protein expression of IL-6, RANKL and OPG on the cells.

RESULTSThe ratio of RANKL/OPG was increased at both mRNA and protein level after HMGB1 stimulation at 10, 30, 100 ng x mL(-1). Inflammatory cytokine IL-6 was upregulated by HMGB1 at the concentration of 100 ng x mL(-1).

CONCLUSIONIncreased ratio of RANKL/OPG and IL-6 on periodontal ligament fibroblasts suggests that HMGB1 might play a role in the pathogenesis and progression of periodontal disease.