Table 1.
Summary of biomarkers of oxidatively damaged DNA, nucleobases, and LPO products used in studies of the effect of combustion particles.
| Biomolecule | Description | Assays |
|---|---|---|
| Oxidatively damaged DNA or nucleobases | ||
| ENDOIII/FPG | DNA base lesions detected by bacterial ENDOIII or FPG enzymes, representing mainly oxidized purine (including 8-oxodG) and pyrimidine lesions, respectively | Comet assay |
| 8-oxodG | Major oxidation product in nuclear DNA; detection of 8-oxodG in urine or plasma mainly originates from oxidation of deoxyguanosine triphosphate in the nucleotide pool | HPLC-ECD, LC-MS/MS, antibodies |
| 8-oxoGua | Major oxidation product in nuclear DNA; detection of 8-oxoGua in urine or plasma is likely to arise from cleavage of the oxidized base from DNA by repair enzymes (e.g., OGG1) | HPLC-ECD, LC-MS/MS, antibodies |
| M1dG | Exocyclic DNA damage formed by reactive carbonyl compounds released from oxidized lipids | LC-MS, antibodies |
| LPO products | ||
| CDs | Breakdown products of fatty acids considered to represent an early stage of the LPO process | Spectrophotometry |
| Lipid hydroperoxides | Reaction product between O2 and carbon radical in lipids | Spectrophotometry |
| MDA/TBARS | Breakdown carbonyl product of LPO; the reaction with thiobarbituric acid forms adducts that can be detected by spectrophotometry; prepurification of urine or plasma before the reaction with thiobarbituric acid can be considered as a specific measurement of LPO products, whereas the simple TBARS assay is highly unspecific | Spectrophotometry |
| F2-isoprostanes | Products that arise mainly from oxidation of arachidonic acid in phospholipids, often referred to as 8-iso-PGF2α or 15-F2t-isoprostanes | GC-MS, LC-MS/MS, antibodies |
Abbreviations: 8-oxodG, 8-oxo-7,8-dihydro-2′-deoxyguanosine; 8-oxoGua, 8-oxo-7,8-dihydroguanine; CDs, conjugated dienes; ECD, electrochemical detection; ENDOIII, endonuclease III; FPG, formamidopyrimidine DNA glycosylase; GC-MS, gas chromatography–mass spectrometry; HPLC, high-performance liquid chromatography; LC-MS, liquid chromatography–mass spectrometry; LC-MS/MS, liquid chromatography with tandem mass spectrometry; LPO, lipid peroxidation; M1dG, exocyclic M1 adduct to guanine; MDA, malondialdehyde; OGG1, 8-oxoguanine DNA glycosylase; TBARS, thiobarbituric acid–reactive substances. For descriptions and critical assessments of the assays as biomarkers, see Griffiths et al. (2002) and Halliwell and Whiteman (2004).