Biological Effects of Light-Emitting Diodes Curing Unit on MDPC-23 Cells and Lipopolysaccharide Stimulated MDPC-23 Cells / 치위생과학회지

BACKGROUND: Light-emitting diodes curing unit (LCU), which emit blue light, is used for polymerization of composite resins in many dentistry. Although the use of LCU for light-cured composite resin polymerization is considered safe, it is still controversial whether it can directly or indirectly have harmful biological influences on oral tissues. The aim of this study was to elucidate the biological effects of LCU in wavelengths ranging from 440 to 490 nm, on the cell viability and secretion of inflammatory cytokines in MDPC-23 odontoblastic cells and inflammatory-induced MDPC-23 cells by lipopolysaccharide (LPS). METHODS: The MTT assay and observation using microscope were performed on MDPC-23 cells to investigate the cell viability and cytotoxic effects on LCU irradiation. RESULTS: MDPC-23 cells and LPS stimulated MDPC-23 cells were found to have no effects on cell viability and cell morphology in the LCU irradiation. Nitric oxide (NO) and prostaglandin E2 which are the pro-inflammatory mediators, and interleukin-1β and tumor necrosis factor-α (TNF-α) which are the proinflammatory cytokines were significantly increased in MCPD-23 cells after LCU irradiation as time increased in comparison with the control. LCU irradiation has the potential to induce inflammation or biological damages in normal dental tissues, including MDPC-23 cells. CONCLUSION: Therefore, it is necessary to limit the use of LCU except for the appropriate dose and irradiation time. In addition, LCU irradiation of inflammatory-induced MDPC-23 cells by LPS was reduced the secretion of NO compared to the LPS alone treatment group and was significantly reduced the secretion of TNF-α in all the time groups. Therefore, LCU application in LPS stimulated MDPC-23 odontoblastic cells has a photodynamic therapy like effect as well as inflammation relief.

Effects of Melatonin on MDPC-23 Cells Differentiation / 체질인류학회지

Melatonin is the major hormone released from the pineal gland and regulates a variety of physiological and pathophysiological processes. According to the recent studies the melatonin plays an important role in regulation of bone growth. The purpose of this study was to determine whether melatonin promotes the cell differentiation and nodules formation in MDPC-23 pre-odontoblast cell line. MDPC-23 cells were cultured for up to 15 days in growth media containing differentiation medium with melatonin or without melatonin. Cultures were stained with Alizarin-S. The expression of the mRNAs for DSPP, OC, ALP and NFI-C were analyzed by RT-PCR. The results were as follows. Cultures containing melatonin at day 15 showed extensive mineralization as compared with control cultures. Melatonin increased the expression of DSPP and OC mRNAs in MDPC-23 cells in a concentration-dependent manner. However, melatonin did not changed ALP expression. Melatonin markedly decreased mRNA expression of NFI-C in early stage cultures as compared with control cultures. These results demonstrated that melatonin is capable of promoting MDPC-23 cells differentiation and mineralization and suggested that melatonin may play an important role in dentin formation.

Role of OD314 During Odontoblast Differentiation / 체질인류학회지

Odontoblasts are responsible for the formation and maintenance of dentin which is a mineralized part in dentin-pulp complex of tooth. OD314 was obtained by subtractive hybridization between odontoblasts and osteoblast/dental papilla cells, and differentiatially expressed in the odontoblasts but not in osteoblasts and dental papilla cells. In this study, to better understand the biological function of new odontoblast-enriched gene, OD314, we examined expression of OD314 in cultured MDPC-23 cells and intracellular localization of OD314 protein. We also evaluate the effect of OD314 over-expression and inactivation on the cells by northern analysis. When MDPC-23 cells are cultured in the differentiation and mineralization medium for 28 days, OD314 mRNA expression was gradually increased from the beginning to day 21 and remained relatively high on day 28. Immunofluorescent staining of cultured MDPC-23 revealed localization of OD314 on the cytoplasm, especially near the nuclear membrane. However, a small amount of fluorescence was also observed in the nucleus. Inactivation of OD314 by RNA interference up-regulated the expression of DSPP, whereas over-expression of OD314 by CMV-OD314 plasmid down-regulated the expression of ON. These results suggest that OD314, a odontoblat-enriched gene, may play important roles in the odontoblast differentiation and dentin mineralization.

Transforming growth factor ?1 induces apoptosis in mouse odontoblast cell line MDPC-23 / 实用口腔医学杂志

Objective:To investigate if transforming growth factor-?1 (TGF-?1) induces apoptosis in odontoblast cell line MDPC-23. Methods:MDPC-23 cells were treated with TGF-?1 at 0.5,2.5 or 10 ng/ml for 48 h,apoptosis of MDPC-23 cells was detected by annexin V and propidium iodide (PI) staining, cell death detection ELISA and DNA electrophoretic analysis. Results: Consistent results were obtained from three different methods.TGF-?1 at 0.5-10 ng/ml induced apoptosis of MDPC-23 cells in a dose-dependent manner. Conclusion:TGF-?1 may paly a role in apoptosis of odontoblasts.