title: [DNA damage in human pleural mesothelial cells induced by exposure to carbon nanotubes].
abstract: OBJECTIVE
  Nanomaterials are currently used in electronics, industrial materials, cosmetics, and medicine because they have useful physicochemical properties, such as strength, conductivity, durability, and chemical stability. As these materials have become widespread, many questions have arisen regarding their effects on health and the environment. In particular, recent studies have demonstrated that carbon nanotubes (CNTs) cause significant inflammation and mesothelioma in vivo. In this study, we investigated the potential risk posed by singlewalled carbon nanotube (SWCNT) and multiwalled carbon nanotube (MWCNT) exposure in human pleural mesothelial cells.
  
  
  METHODS
  CNT cytotoxicity was determined by a trypan blue exclusion assay, and DNA damage was detected by an alkaline comet assay. The concentration of 8-oxodeoxyguanosine (8-OHdG) in DNA was measured by high perhormance liquid chromatography with electrochemical detection. The expression of base excision repair enzymes in the cell was estimated by immunoblot analysis.
  
  
  RESULTS
  We observed inhibitory effects on cell proliferation and the induction of DNA damage following exposure of cells to purified CNTs that were suspended in dispersion medium. However, accumulation of 8-OHdG in DNA was not found. In addition, the expression levels of base excision enzymes that are involved in hOGG1, hMTH1, and MYH in MeT-5A cells remained unchanged for 24 h after carbon nanotube exposure.
  
  
  CONCLUSIONS
  CNTs significantly inhibit cell proliferation and decrease DNA damage in human pleural mesothelial cells. Our results indicate that the mechanism of CNT-induced genotoxicity is different from that following exposure to reactive oxygen species, which causes oxidative DNA modifications and 8-OHdG production. Further investigation is required to characterize the specific DNA mutations that occur following CNT exposure.
authors.affiliation: Department of Hygienic Chemistry, Meiji Pharmaceutical University, Kiyose-shi, Tokyo, Japan. yo@my-pharm.ac.jp
authors.forename: Yuki
authors.initials: Y
authors.lastname: Ogasawara
authors.forename: Noriaki
authors.initials: N
authors.lastname: Umezu
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Ishii
mesh_terms: D002478:Cells, Cultured; D020552:Comet Assay; D004249:DNA Damage / Q000502:physiology*; D004847:Epithelial Cells / Q000187:drug effects*; D006801:Humans; D037742:Nanotubes, Carbon / Q000633:toxicity*; D010994:Pleura / Q000187:drug effects
chemical_list: D037742:Nanotubes, Carbon