Effects of TEGDMA and HEMA on the expression of COX-2 and iNOS in cultured murine macrophage cells

Objective This study is aimed to investigate the effects of triethyleneglycol dimethacrylate (TEGDMA) and 2-hydroxyethyl methacrylate (HEMA) on expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in cultured murine macrophage cell line RAW 264.7. Methods For mRNA gene expression analysis of COX-2 and iNOS, RAW 264.7 cells were exposed to TEGDMA and HEMA, and mRNA of each gene was observed by using a reverse transcriptase polymerase chain reaction (RT-PCR) assay. The Western blotting method was applied for detection of COX-2 and iNOS proteins extracted from RAW 264.7 cells treated with the resin monomers. Prostaglandin E2 (PGE(2)) was quantified by immunoassay with commercially available ELISA kits. Results TEGDMA and HEMA induced the expression of COX-2 mRNA dose-dependently in RAW 264.7 cells. The expression of COX-2 mRNA was up-regulated at 5 h of exposure to both TEGDMA and HEMA, and diminished thereafter. The resin monomers did not affect the expression of iNOS mRNA. Up-regulation of COX-2 protein was confirmed in the cells treated with TEGDMA and HEMA. Production of PGE(2) was also enhanced by TEGDMA. However, HEMA did not affect PGE(2) biosynthesis, although HEMA up-regulated the expression of COX-2 mRNA and protein. Significance These findings suggest that TEGDMA and HEMA can be a critical factor of inflammation related to resin-based dental biomaterials, and that COX-2 is involved in the inflammatory reaction of the resin monomers.