title: Evaluating chromosomal damage in workers exposed to hexavalent chromium and the modulating role of polymorphisms of DNA repair genes.
abstract: OBJECTIVE
  Welders have been chronically exposed to hexavalent chromium with potential consequences on chromosomal integrity. Our study is focused on the extent of any such chromosomal aberrations with respect to chromium levels in the blood of welders as well as on the tentative modulating role of polymorphisms in DNA repair genes XPD Lys751Gln, XPG Asn114His, XPC Lys939Gln, hOGG1 Ser326Cys and XRCC1 Arg399Gln on chromosomal damage.
  
  
  METHODS
  The study was conducted on 144 individuals consisting of 73 welders exposed to chromium for 10.2 ± 1.67 years and 71 control individuals without known exposures. Chromosomal aberrations, their chromatid-type and chromosome-type aberrations were detected by conventional cytogenetic analysis. XPD, XPG, XPC, hOGG1 and XRCC1 gene polymorphisms were assayed for by Taqman SNP genotyping assay ("Assay-by-Demand") using Real-Time allelic discrimination on AB 7500 equipment. Chromium concentration in the blood was determined by atomic absorption spectrophotometry.
  
  
  RESULTS
  The level of chromium in the blood of welders ranged between 0.032 and 0.182 μmol l(-1) and was significantly higher than that in controls (0.07 ± 0.04 μmol l(-1) vs. 0.03 ± 0.007 μmol l(-1)). Parameters of chromosomal damage were similar in both the exposed and the control individuals (1.89% vs. 1.70% for total chromosomal aberrations, 0.97% vs. 0.88% for chromosome-type and 0.92% vs. 0.80% for chromatid-type, respectively). Chromatid-type of aberrations positively correlated with the level of chromium in the blood (r = 0.28; P = 0.02). Significantly higher total chromosomal aberrations were detected in individuals with homozygous variant polymorphism in XRCC1 Arg399Gln gene as compared to those with heterozygous and homozygous wild-type genotypes (2.20, 1.89 and 1.48%, respectively; P = 0.01). A similar tendency was found for chromatid-type aberrations (1.30% for homozygous variant genotype bearers, 0.94% for those with heterozygous genotype and 0.75% for carriers of homozygous wild-type genotype, respectively; P = 0.04).
  
  
  CONCLUSIONS
  Although no apparent increase in chromosomal damage was recorded in chromium-exposed welders in comparison with controls, genetic make-up in DNA repair genes may increase susceptibility toward adverse effect of chromium.
authors.affiliation: Department of Medical Biology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Mala Hora 4, 03645, Martin, Slovakia. halasova@jfmed.uniba.sk
authors.forename: Erika
authors.initials: E
authors.lastname: Halasova
authors.forename: Tatiana
authors.initials: T
authors.lastname: Matakova
authors.forename: Ludovit
authors.initials: L
authors.lastname: Musak
authors.forename: Veronika
authors.initials: V
authors.lastname: Polakova
authors.forename: Lucia
authors.initials: L
authors.lastname: Letkova
authors.forename: Dusan
authors.initials: D
authors.lastname: Dobrota
authors.forename: Pavel
authors.initials: P
authors.lastname: Vodicka
mesh_terms: D000328:Adult; D002274:Carcinogens, Environmental / Q000032:analysis / Q000633:toxicity*; D002857:Chromium / Q000097:blood / Q000633:toxicity*; D002869:Chromosome Aberrations / Q000139:chemically induced*; D004260:DNA Repair / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects* / Q000032:analysis*; D011110:Polymorphism, Genetic / Q000187:drug effects / Q000235:genetics; D018154:Slovakia; D014896:Welding
chemical_list: D002274:Carcinogens, Environmental; D002857:Chromium; C074702:chromium hexavalent ion