Introduction: For dental treatment, dentin regeneration is required after a tooth injury with dental pulp exposure. The effects of the water-soluble matrix (WSM) extracted from the nacreous layer of the bivalve Pinctada maxima on human dental pulp cells in vitro were challenging and useful for clinical application.
Material and methods: The biological activity of the STRO-1-positive human dental pulp cells in response to WSM compared to Dulbecco's modified Eagle medium (DMEM) as a normal control was monitored. The cell survival rate was analyzed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Proteomic profiles among inducers and noninducers with time dependency were compared by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis combined with liquid chromatography-tandem mass spectrometry (GeLC-MS/MS).
Results: The human dental pulp cells cultured in nacreous WSM exhibited higher relative cell viability than those in DMEM with similar morphological appearance. Significant changes were found in the relative abundance of 44 proteins in cells after exposure to WSM for 2 weeks. They play a role in cell adhesion, cell proliferation, metabolic process, signal transduction, stress response, transcription, translation, and transport.
Conclusion: These results indicate that WSM of P. maxima has the ability to induce proliferation of human dental pulp cells.
Clinical relevance: This finding initiated the study to evaluate the suitability of nacre as biomaterial for dentistry.