MTA stimulates BMP2 expression in human PDL cells

Objectives: We reported in the last IADR conference that MTA upregulated osteopontin and osteocalcin expression in human PDL cells (HPLF) through the calcium release. In this study we aimed to analyze how MTA induced the osteoblastic differentiation of HPLF. Methods: Two HPLF populations were isolated and generated from the healthy premolars of a 22-year-old female, and a 14-year-old male who visited Kyushu University Hospital for extraction, and cells were maintained in 10%FBS/aMEM (Gibco-BRL, Grand Island, NY). All procedures were performed in compliance with the regulations of Kyushu University. White ProRoot MTA (DENTSPLY Tulsa Dental, Johnson City, TN) was mixed with sterilized distilled water according to the manufacturer's instructions, dispensed into plastic lids of 1.5ml micro-centrifuge tubes, and placed in a humidified incubator (37°C) for 12hr. MTA discs f9mm) were then rinsed with aMEM, placed in 24-well culture plates (1disk/well), and subjected to the cultures with HPLF. Co-cultured HPLF were exposed to the immunocytochemistry, RT-PCR analyses, and von Kossa staining. Results: MTA and CaCl2, but not MgCl2 stimulated BMP2 mRNA expression in HPLF-2H and -2I. BMP2-expressing cells were observed close to MTA by immunocytochemical staining. Both HPLFs expressed BMP2 receptors mRNA, BMPR-IA and BMPR-II, but not BMPR-IB. The expression of BMPR-IA in HPLF was also confirmed by immunocytochemical staining. Not only MTA, but CaCl2 induced mineralization in both HPLFs. Conclusion: The present results suggested that MTA induced the osteogenic differentiation of HPLFs through upregulated BMP2 expression via calcium release, and that MTA is a bioactive material in endodontic treatment.