Tannin-Fluoride Preparation Attenuated Prostaglandin E₂ Production in Dental Pulp Cells

Objectives: Tannic acid is a water-soluble polyphenol, and have been shown to exert various biological effects ranging from anti-inflammatory to anticancer and antiviral effects. Little is known regarding the possible effects of tannic acid in dental pulp cells. Glass ionomer cements (GIC) have a good biocompatibility and have been widely used for operative restoration of caries cavities. On the other hand, it was reported that the components of GIC diffused into dental pulp through dentinal tubules and cause pulpal inflammatory responses. Recently, GIC containing tannin-fluoride preparation (HY agent) were developed. In this study, we investigated the effect of tannic acid on prostaglandin E₂ (PGE₂) release from dental pulp cells. Methods: GIC disks with (HY(+))/ without (HY(-)) HY agent or with Y agent (Y) which is mainly composed of tannic acid, were exposed to Dulbecco's modified Eagle medium (DMEM) and applied to RPC cells cultures. DMEM was employed as control. After treatment with GIC extracts, ATP contents, mRNA and protein expressions in RPC cells and PGE₂ contents in culture media were analyzed. Results: There is no significant difference in ATP contents after 48 hr treatment in each group. HY and Y agents suppressed HY(-) GIC-induced COX-2 mRNA expression in RPC cells. Tannic acid reduced COX-2 mRNA induction by HY(-) GIC in dental pulp cells depending on its concentration. HY and Y agents suppressed HY(-) GIC-stimulated PGE2 release from RPC cells after 12 hr. The extract of all GIC increased expression of COX-2 protein and phosphorylation of IκBα, ERK and p38. HY agent inhibited these reactions. Conclusion: Taken together, these results suggest that extract of GIC induces PGE₂ production of dental pulp cells and that tannic acid in HY agent suppresses PGE₂ release from dental pulp cells by inhibition of MAP kinase and NF-κB activation.