title: Inhibitory effects of root canal sealers on the expression of inducible nitric oxide synthase in lipopolysaccharide-stimulated murine macrophage cells.
abstract: Excessive production of nitric oxide (NO) is associated with inflammation. In the present study, we examined the effects of root canal sealers (N2 Universal, Sealapex, and AH26) on NO production and inducible NO synthase (iNOS) expression in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. Root canal sealers decreased NO synthesis in LPS-induced RAW 264.7 macrophages in a dose-dependent manner. RT-PCR and Western blot analysis demonstrated markedly lower levels of iNOS mRNA and protein in LPS-activated macrophage cells treated with root canal sealers compared with untreated cells. From these results, we conclude that root canal sealers do not inhibit NO synthesis by direct inhibition of the enzyme, but rather through inhibition of iNOS mRNA expression (leading to a decrease in iNOS protein expression). Our data, therefore, suggest that root canal sealers may be an effective inhibitor of LPS-induced inflammatory effects in macrophage cells. Further in vitro and in vivo studies are necessary to confirm the effects of root canal sealers on the inflammatory processes.
authors.affiliation: Department of Dental Biomaterials Science, Dental Research Institute, College of Dentistry, Seoul National University, Chongro-ku, Seoul 110-749, Korea.
authors.forename: Dong Hee
authors.initials: DH
authors.lastname: Lee
authors.forename: Bum-Soon
authors.initials: BS
authors.lastname: Lim
authors.forename: Yong-Keun
authors.initials: YK
authors.lastname: Lee
authors.forename: Na Ryoung
authors.initials: NR
authors.lastname: Kim
authors.forename: Hyeong-Cheol
authors.initials: HC
authors.lastname: Yang
mesh_terms: D000818:Animals; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D008070:Lipopolysaccharides / Q000276:immunology / Q000494:pharmacology*; D008264:Macrophages / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology* / Q000276:immunology; D051379:Mice; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism*; D009573:Nitrites / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012387:Root Canal Filling Materials / Q000494:pharmacology*
chemical_list: D008070:Lipopolysaccharides; D009573:Nitrites; D012333:RNA, Messenger; D012387:Root Canal Filling Materials; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II