title: Epigallocatechin-3-gallate blocks triethylene glycol dimethacrylate-induced cyclooxygenase-2 expression by suppressing extracellular signal-regulated kinase in human dental pulp and embryonic palatal mesenchymal cells.
abstract: BACKGROUND
  Methacrylate resin-based materials could release components into adjacent environment even after polymerization. The major components leached include triethylene glycol dimethacrylate (TEGDMA). TEGDMA has been shown to induce the expression of cyclooxygenase-2 (COX-2). However, the mechanisms are not completely understood. The aims of this study were to investigate the molecular mechanism underlying TEGDMA-induced COX-2 in 2 oral cell types, the primary culture of human dental pulp (HDP) cells and the human embryonic palatal mesenchymal (HEPM) pre-osteoblasts, and to propose potential strategy to prevent or ameliorate the TEGDMA-induced inflammation in oral tissues.
  
  
  METHODS
  TEGDMA-induced COX-2 expression and its signaling pathways were assessed by Western blot analyses in HDP and HEPM cells. The inhibition of TEGDMA-induced COX-2 protein expression using various dietary phytochemicals was investigated.
  
  
  RESULTS
  COX-2 protein expression was increased after exposure to TEGDMA at concentrations as low as 5 μmol/L. TEGDMA-induced COX-2 expression was associated with reaction oxygen species, the extracellular signal-regulated kinase 1/2, and the p38 mitogen-activated protein kinase signaling pathways in HDP and HEPM cells. The activation of p38 mitogen-activated protein kinase was directly associated with reactive oxygen species. Epigallocatechin-3-gallate suppressed TEGDMA-induced COX-2 expression by inhibiting phosphorylation of extracellular signal-regulated kinase 1/2.
  
  
  CONCLUSIONS
  Cells exposed to low concentrations of TEGDMA may induce inflammatory responses of the adjacent tissues, and this should be taken into consideration during common dental practice. Green tea, which has a long history of safe beverage consumption, may be a useful agent for the prevention or treatment of TEGDMA-induced inflammation in oral tissues.
authors.affiliation: School of Dentistry, National Taiwan University Hospital, National Taiwan University, Taipei, Taiwan.
authors.forename: Wan-Hsien
authors.initials: WH
authors.lastname: Yang
authors.forename: Yi-Ting
authors.initials: YT
authors.lastname: Deng
authors.forename: Mark Yen-Ping
authors.initials: MY
authors.lastname: Kuo
authors.forename: Cheing-Meei
authors.initials: CM
authors.lastname: Liu
authors.forename: Hao-Hueng
authors.initials: HH
authors.lastname: Chang
authors.forename: Jenny Zwei-Chieng
authors.initials: JZ
authors.lastname: Chang
mesh_terms: D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D018929:Cell Culture Techniques; D002460:Cell Line; D002478:Cells, Cultured; D003188:Composite Resins / Q000494:pharmacology*; D051546:Cyclooxygenase 2 / Q000187:drug effects*; D052246:Cyclooxygenase 2 Inhibitors / Q000494:pharmacology*; D003782:Dental Pulp / Q000187:drug effects / Q000201:enzymology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000187:drug effects*; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects; D059630:Mesenchymal Stem Cells / Q000187:drug effects / Q000201:enzymology*; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000187:drug effects; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000187:drug effects; D010006:Osteoblasts / Q000187:drug effects / Q000201:enzymology; D010159:Palate / Q000166:cytology*; D011092:Polyethylene Glycols / Q000494:pharmacology*; D011109:Polymethacrylic Acids / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000187:drug effects
chemical_list: D003188:Composite Resins; D052246:Cyclooxygenase 2 Inhibitors; D011109:Polymethacrylic Acids; D017382:Reactive Oxygen Species; C020946:triethylene glycol dimethacrylate; D011092:Polyethylene Glycols; D002392:Catechin; C045651:epigallocatechin gallate; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D048049:Extracellular Signal-Regulated MAP Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases
keywords: Cyclooxygenase-2; epigallocatechin-3-gallate; human embryonic palatal mesenchymal; pulp; triethylene glycol dimethacrylate