title: Protective effect of NAC on formaldehyde-containing-ZOE-based root-canal-sealers-induced cyclooxygenase-2 expression and cytotoxicity in human osteoblastic cells.
abstract: Cyclooxygenase-2 (COX-2) is an inducible enzyme believed to be responsible for prostaglandin synthesis at site of inflammation. Recently, the activation of COX-2 expression may be one of the important pathogenesis of root-canal-sealers-induced periapical inflammation. However, little is known about whether chemical interaction can modulate the COX-2 expression and cytotoxicity induced by formaldehyde-containing-ZOE-based root canal sealers. The aim of this study was to investigate the effects of antioxidants such as catalase, superoxide dismutase (SOD), and N-acetyl-L-cysteine (NAC) on N2- and endomethasone-induced COX-2 mRNA gene and cytotoxicity in human osteoblastic cell line U2OS cells. Our data demonstrated that both formaldehyde-containing-ZOE-based root canal sealers were found to induce COX-2 mRNA gene expression in U2OS cells. The addition of glutathione (GSH) precursor NAC led to decrease the induction of COX-2 mRNA gene expression and cytotoxicity by both N2 and Endomethasone (p < 0.05). However, catalase and SOD lacked the ability to prevent cytotoxicity and COX-2 mRNA gene expression induced by N2 and Endomethasone (p > 0.05). The data presented here demonstrated that the activation of COX-2 mRNA gene expression may be one of the pathogenesis of formaldehyde-containing-ZOE-based root-canal-sealers-induced periapical inflammation. In addition, GSH depletion, but not the attack of oxygen free radicals, could be the mechanism for cytotoxicity and COX-2 mRNA gene expression induced by formaldehyde-containing-ZOE-based root canal sealers. NAC appears as a useful agent in protecting cell damage mediated by formaldehyde-containing-ZOE-based root canal sealers.
authors.affiliation: Department of Prosthodontics, Oral Medicine Center, Chung Shan Medical University Hospital, Taichung, Taiwan.
authors.forename: Fu-Mei
authors.initials: FM
authors.lastname: Huang
authors.forename: Lin Shin-Shen
authors.initials: LS
authors.lastname: Chou
authors.forename: Ming-Yung
authors.initials: MY
authors.lastname: Chou
authors.forename: Yu-Chao
authors.initials: YC
authors.lastname: Chang
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D051546:Cyclooxygenase 2 / Q000096:biosynthesis* / Q000633:toxicity; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology*; D005557:Formaldehyde / Q000037:antagonists & inhibitors / Q000633:toxicity; D006801:Humans; D010006:Osteoblasts / Q000187:drug effects* / Q000201:enzymology*; D012333:RNA, Messenger / Q000096:biosynthesis; D012387:Root Canal Filling Materials / Q000633:toxicity*; D015035:Zinc Oxide-Eugenol Cement / Q000494:pharmacology*
chemical_list: D016861:Cyclooxygenase Inhibitors; D012333:RNA, Messenger; D012387:Root Canal Filling Materials; D015035:Zinc Oxide-Eugenol Cement; D005557:Formaldehyde; D051546:Cyclooxygenase 2; D000111:Acetylcysteine