Inorganic phosphate stimulates apoptosis in murine MO6-G3 odontoblast-like cells

• Published in: Archives of oral biology 2011-10, Vol.56 (10), p.977-983
• Main Authors: Bourgine, A, Beck, L, Khoshniat, S, Wauquier, F, Oliver, L, Hue, E, Alliot-Licht, B, Weiss, P, Guicheux, J, Wittrant, Y
• Format: Article
• Language: English
• Subjects: Advanced Basic Science; Animal models; Animals; Annexin A5 - analysis; Annexin V; Antibodies, Monoclonal; Apoptosis; Apoptosis - drug effects; Benzimidazoles; Biomarkers - analysis; Calcium - pharmacology; Caries formation; Cell Count; Cell culture; Cell Line; Cell Nucleus - ultrastructure; Cell proliferation; Cell Proliferation - drug effects; Cell Survival - drug effects; Chondrocytes; Colorimetry; Coloring Agents; Crystals; Culture Media; Demineralization; Dental caries; Dental enamel; Dentistry; Enumeration; Enzyme Inhibitors - analysis; Flow Cytometry; Formazans; Indicators and Reagents; Inorganic phosphate; Life Sciences; Mice; Nuclei; Odontoblast; Odontoblasts; Odontoblasts - drug effects; Osteoblasts; Phosphate; Phosphates - pharmacology; Teeth; Tooth; Trypan Blue
• ISSN: 0003-9969; 1879-1506
• DOI: 10.1016/j.archoralbio.2011.03.001

Abstract Objective Dental pathologies such as caries are the most prevalent disease worldwide with infectious and social complications. During the process of caries formation, the tooth is degraded and demineralization of enamel and dentine leads to the release of large amounts of inorganic phosphate (Pi) within dental tubuli. As Pi has been shown to induce apoptosis in skeletal cells, including osteoblasts and chondrocytes, we questioned whether high concentrations of Pi could affect odontoblast viability, proliferation and apoptosis. Design Using the odontoblast-like MO6-G3 cell line as a model, we used cell counting and MTS-based colorimetric assays to measure cell viability and proliferation. Apoptosis was assessed using Hoechst nuclei staining and detection of the early apoptotic markers annexin V and Apo2.7. Results We show for the first time that a high Pi concentration (7 mM) induced a decrease in odontoblast viability and proliferation together with a large increase in apoptosis. These effects were blunted in calcium-free medium, possibly due to the formation of calcium-phosphate crystals in the presence of high Pi concentrations. Conclusion This study contributes to clarifying the effect of Pi on odontoblast viability and apoptosis, which may improve our understanding of the role of Pi during caries formation.