title: Ameliorated chrysotile-induced DNA damage in human embryo lung cells by surface modification of chrysotile with rare earth compounds.
abstract: OBJECTIVE
  In view of the fact that asbestos is not only a key occupational hazard, but also an important environmental pollutant, it is necessary to develop a proper method to decrease the carcinogenicity of asbestos fibers. This study was designed to determine if the surface modification of chrysotile asbestos fiber (CAF) with rare earth compounds (REC) can ameliorate CAF-induced DNA damages in human embryo lung (HEL) cells.
  
  
  METHODS
  After incubation with REC solution at different concentrations at room temperature for 1 h, natural and REC-pretreated CAF was added to cell culture at various doses. At the selected time as the experiment designed, DNA damages of the HEL cells were detected by Unscheduled DNA Synthesis (UDS) and Single Cell Gel Electrophoresis (SCGE) assays.
  
  
  RESULTS
  The UDS induced by natural CAF was elevated with the increase of CAF doses. There was a good dose-response relationship between the UDS and the amount of CAF in the medium and the coefficient of correlation (R) was 0.958 at P < 0.05. In REC-pretreated CAF groups, the UDS declined with the increase of REC doses. Both catalase (CAT) and dimethylsulfoxide (DMSO) also reduced the CAF-induced enhancement of UDS. In SCGE assay, CAF induced DNA chain breakage and the magnitude of DNA chain breakage increased in a dose-dependent manner and the coefficient of correlation (R) was 0.992 at p < 0.01, while REC-pretreated CAF significantly decreased the induction of DNA chain breakage in a dose-dependent manner (r = 0.989, p < 0.05).
  
  
  CONCLUSIONS
  It can be concluded that CAF-induced DNA damages in HEL cells may be partly mediated by oxygen derivatives, and the surface modification of CAF with REC might hide critical sites on the fiber surface, thereby reducing the fiber-mediated production of oxygen derivation and lowering the CAF-induced UDS and DNA chain breakage in HEL cells.
authors.affiliation: National Center for Occupational Safety Science and Technology, Beijing 100029, China.
authors.forename: J G
authors.initials: JG
authors.lastname: Fan
authors.forename: Q E
authors.initials: QE
authors.lastname: Wang
authors.forename: S J
authors.initials: SJ
authors.lastname: Liu
mesh_terms: D017632:Asbestos, Serpentine / Q000009:adverse effects* / Q000737:chemistry; D002450:Cell Communication; D018929:Cell Culture Techniques; D004249:DNA Damage; D004305:Dose-Response Relationship, Drug; D004785:Environmental Pollutants / Q000009:adverse effects*; D006801:Humans; D008168:Lung / Q000196:embryology; D008674:Metals, Rare Earth / Q000737:chemistry*; D010100:Oxygen
chemical_list: D017632:Asbestos, Serpentine; D004785:Environmental Pollutants; D008674:Metals, Rare Earth; D010100:Oxygen