Enamel matrix derivative neutralized the effect of lipopolysaccharide on osteoprotegerin and receptor activator of nuclear factor kappa B ligand expression of osteoblasts

Objective: In this study, we investigated the effects of enamel matrix derivative (EMD) on osteoprotegerin (OPG) and receptor activator of nuclear factor kappa B ligand (RANKL) expression of osteoblasts in the presence of lipopolysaccharide (LPS). Study design: OPG and RANKL gene expression and protein synthesis of MC3T3-E1 osteoblastic cells were examined by reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay. Results: LPS inhibited OPG gene expression and protein synthesis, and stimulated RANKL gene expression and soluble RANKL synthesis. EMD enhanced OPG gene expression and protein synthesis, and inhibited RANKL gene expression and soluble RANKL synthesis. Furthermore, EMD neutralized the effects of LPS on OPG and RANKL expression in osteoblasts. Conclusions: EMD might regulate the function of osteoblasts; by elevating the ratio of OPG/RANKL gene expression, which is downregulated by LPS, and suppress the induction of osteoclastogenesis. Thereby, EMD might contribute to periodontal tissue regeneration. (C) 2009 Elsevier Ltd. All rights reserved.