| Budget Amount *help |
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 2002: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 2001: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
Recently, it was demonstrated that platelet-derived growth factor (PDGF) controls the expression of alkaline phosphatase and proteoglycan synthesis of odontoblastic cells in dental pulp tissues. Although PDGF appears to be closely related to dentinogenesis, much about the mode of action of PDGF on odontoblast differentiation remains unclarified. In this study, we examined the effects of PDGF isoforms (PGDF-AA, -AB, and -BB) on odontoblastic differentiation of dental pulp cells in long-term mineralized cultures. Dental pulp cells isolated from rat lower incisors were continuously treated with each of PDGF-AA, -AB, and -BB in separate cultures for 20 days. Three PDGF isoforms suppressed the alkaline phosphatase activity, osteocalcin and calcium contents, and the formation of dentin-like nodules. The expression of the mRNA for dentin siatoprotein (DSP) in the cells was inhibited by PDGF-AA treatment, whereas PDGF-AB and -BB treatment stimulated the expression, even though the dentin-like nodule formation was inhibited. Although the effects of PDGF on odontoblastic differentiation varied among the isoforms, the cells expressed both PDGF α and β receptors, whose quantities were similar. These results suggest that PDGF exerts diverse effects on odontoblastic differentiation depending on the isoform type. These in vitro findings explain at least in part the in vivo action of PDGF in dentinogenesis during the repair process of damaged dental pulp.
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