Effects of Dexamethasone and/or BMP-6 on the Cementoblasts, In Vitro

OBJECTIVES: Periodontal regeneration is a complex biological process comprising regeneration of multiple tissues including cementum, periodontal ligament and bone .This process involves regulated interactions between cells, locally acting growth factors, systemic hormones and growth factors. The purpose of this study was to evaluate the proliferative capacity of cementoblasts by continuous monitoring and to investigate the effects of Dexamethasone (Dex) and Bone Morphogenetic Protein-6 (BMP-6) treatment on Bone sialoprotein (BSP) mRNA expression of cementoblasts. METHODS: OCCM.30 murine immortalized cementoblasts were cultured with different concentrations of BMP-6 (10, 50, and 100 ng/ml) and/or Dex (10-6M). Proliferation of cells was evaluated using real time xCELLigence system. After seeding 200µL of the cell suspensions into the wells (5000 cells/well) of the E-plate 96, OCCM.30 cells were monitored every 15 min for a period of 126 hrs. After 72 hours, total RNA was isolated and mRNA levels for BSP-bone/cementum marker- was investigated by real-time quantitative RT-PCR (Q-PCR). RESULTS: Following real-time analysis, significantly increased proliferative activity was observed in the OCCM.30 treated with Dex when compared with the control group. While all concentrations of BMP-6 increased proliferation of OCCM.30 cells slightly, the addition of Dex to BMP-6 reduced this proliferative activity to the level of control group. BMP-6 induced BSP mRNA expression in a dose-dependent manner. Dex alone also induced BSP transcript. The addition of Dex to BMP-6 enhanced BSP mRNA expression (3 folds) when compared to Dex alone and BMP-6 (100 ng/ml) alone. CONCLUSION:These results indicate that BMP-6 and DEX are important biological regulators of cementoblast differentiation, having the potential to be used in periodontal tissue engineering applications. In vivo experiments using BMP-6 and Dex loaded scaffolds may provide further evidence to support the use of these constructs to repair and regenerate damaged or lost mineralized tissues.