The effect of interleukin-6 on the expression of receptor activater of NF[Kappa]B ligand, osteoprotegerin and microphage colony stimulating factor in human dental pulp fibroblast

Abstract

Interleukin-6 (IL-6) is a highly pleiotropic cytokine that mediates the host inflammation and known to influence osteoclast formation and bone resorption. The aim of this study was to investigate the effects of IL-6 and combination of IL-6 and soluble IL-6 receptor (sIL -6R) on the expression of Receptor activator of NF kappa B ligand (RANKL), Osteoprotegerin (OPG) and Macrophage colony stimulating factor (M-CSF) in human dental pulp (HDP) cells cultures. Culture of HDP cells was established from the explant of pulp tissue. HDP cells were cultured in the presence of 0-10 ng/ml of IL-6. In another experiment sIL-6R ranging from 1-10 ng/ml was added in combination with IL-6. The expression of RANKL, M-CSF and OPG were determined using RT-PCR, western blot analyses an ELISA. Results indicated that IL-6 significantly increased RANKL expression at both mRNA and protein levels in dose-dependent manner but had no effect on the expression of M-CSF and OPG. IL-6+SIL-6 increased RANKL in mRNA level but had not affect on OPG and M-CSF and M-CSF expression. In contrast, RANKL and OPG protein were decreased following increased of SIL-6R. This study may lead to the implication that increasing IL-6 level in inflamed dental pulp may affect on mineralized tissue resorption due to the imbalance of RANKL/OPG system. Moreover, the combination of IL-6 and sIL-6R had decreased RANKL and OPG expression in protein level.