培養歯髄細胞におけるBMP発現とTNF-αの影響

抄録

Narrowed dental puIp cavities and obturated root canals produced by diffuse calcification and pulp stone are often observed in advanced periodontal disease. Possibly inflammatory cytokines following periodontitis may have served as the stimulus inducing the pulp calcification, but the details are not clear.
The purpose of this study was to investigate the relation between pulp calcification and the bone morphogenetic proteins (BMPs) expressed in the dental pulp cells of advanced periodontitis cultivated in vitro, and to analyze the effect of tumor necrosis factor-α (TNF-α) stirnulation on the expression of BMPs. The calcification process of the dental pulp cells was examined by alcian blue staining, von Kossa staining, immunostaining methods (BMP-2, BMP-4, osteonectin, osteocalcin and OB-cadherin) and mapping with combined microanalyzers. The mRNA expression of BMP-2, BMP-4 and transforming growth factor-β2 (TGF-β2) was investigated by reverse transcription-polymerase chain reaction (RT-PCR) methods. Dental pulp cells formed some nodules at 4 weeks of the cultivation in the medium without ascorbic acid and β-glycerophosphate. They included alcian blue-positive glucosaminoglycans, osteonectin, osteocalcin and TGF-β2. The cells in the periphery of nodules seemed to be differentiated odontoblastic cells. The nodules showed calcification at 8 weeks after cultivation by mapping with combined microanalyzers and von Kossa staining. The nodules were positive for BMP-2 and BMP-4 at 4 and 8 weeks after cultivation. BMP-4 expression increased with TNF-α stimulation, while BMP-2 expression decreased. The results suggest that TNF-α probably serves as a kind of stimulus in dental pulp calcification of teeth with periodontitis.