title: Assessment of reference values for DNA damage detected by the comet assay in human blood cell DNA.
abstract: Genotoxicity measured by the comet assay is expressed by different researchers using parameters that are not easy to conceptualize, except for percent tail DNA (%T) or visual score (arbitrary units). A total of 125 publications have reported genotoxicity as DNA damage (representing strand breaks, alkaline labile sites, and transient repair sites), endonuclease III (ENDOIII), or formamidopyrimidine DNA glycosylase (FPG) sensitive sites. I have recalculated the visual score so that it is expressed in the range of 0-100, similar to that of %T. Similar values were obtained for DNA damage and ENDOIII sites, regardless of whether of the data were reported as %T or visual score. Thus, these endpoints can be used interchangeably, assuming that the visual score is expressed in the 0-100 range. Pooled analysis of %T and visual score data showed that the median (25-75%) values of DNA damage, ENDOIII, and FPG sites were 8.6 (4.4-14.5), 11.0 (4.2-19.5), 7.6 (3.2-14.2), respectively. The duration of alkaline treatment and electrophoresis had no significant effect on the level of DNA damage. There was a positive correlation between age and the level of DNA damage. A sub-analysis of DNA damage obtained from European countries showed a negative correlation with latitude. In conclusion, reference values for DNA lesions measured by the comet assay are around 7-11 %T or arbitrary units.
authors.affiliation: Institute of Public Health, University of Copenhagen, Øster Farimagsgade 5, 2-floor, DK-1014 Copenhagen K, Denmark. p.moller@pubhealth.ku.dk
authors.forename: Peter
authors.initials: P
authors.lastname: Møller
mesh_terms: D017677:Age Distribution; D001773:Blood Cells / Q000502:physiology*; D020552:Comet Assay; D004247:DNA / Q000235:genetics* / Q000378:metabolism; D004249:DNA Damage; D043382:DNA-Formamidopyrimidine Glycosylase / Q000378:metabolism; D005060:Europe; D005843:Geography; D006801:Humans; D012016:Reference Values
chemical_list: D004247:DNA; D043382:DNA-Formamidopyrimidine Glycosylase