Suppressive effects of nicotine on the cytodifferentiation of murine periodontal ligament cells.

OBJECTIVES: Tobacco smoking has been suggested to be one of the important risk factors of developing periodontal disease. Although epidemiological studies have shown the detrimental effects of smoking on periodontal disease, the effects of smoke compounds on gingival tissue are not well understood. The aim of this study was to evaluate the effects of nicotine, which is the major component of the thousands of chemicals that constitute cigarette smoke, for cytodifferentiation of murine periodontal ligament (MPDL) cell. MATERIALS AND METHODS: Expression of nAChR subunits on MPDL cells was examined using RT-PCR. The effects of nicotine on gene expression of extracellular matrices and osteoblastic transcription factors were evaluated by quantitative RT-PCR. Mineralized nodule formation of nicotine-treated MPDL cells was characterized by alizarin red staining. RESULTS: Murine periodontal ligament cells expressed several subunits of nAChR, which have functional calcium signals in response to nicotine. Gene expression of extracellular matrices and osteoblastic transcription factors were reduced in nicotine-treated MPDL cells. In addition, mineralized nodule formation was inhibited in MPDL cells in the presence of nicotine. CONCLUSION: Our findings indicate that nicotine may negatively regulate the cytodifferentiation and mineralization of MPDL cells.