Assessment of oxidative DNA damage formation by organic complex mixtures from airborne particles PM(10).
The free radical generating activity of airborne particulate matter (PM(10)) has been proposed as a primary mechanism in biological activity of ambient air pollution. In an effort to determine the impact of the complex mixtures of extractable organic matter (EOM) from airborne particles on oxidative damage to DNA, the level of 8-oxo-2'-deoxyguanosine (8-oxodG), the most prevalent and stable oxidative lesion, was measured in the human metabolically competent cell line Hep G2. Cultured cells were exposed to equivalent EOM concentrations (5-150microg/ml) and oxidative DNA damage was analyzed using a modified single cell gel electrophoresis (SCGE), which involves the incubation of whole cell DNA with repair specific DNA endonuclease, which cleaves oxidized DNA at the sites of 8-oxodG. EOMs were extracted from PM(10) collected daily (24h intervals) in three European cities: Prague (Czech Republic, two monitoring sites, Libus and Smíchov), Kosice (Slovak Republic) and Sofia (Bulgaria) during 3-month sampling periods in the winter and summer seasons. No substantial time- and dose-dependent increase of oxidative DNA lesions was detected in EOM-treated cells with the exception of the EOM collected at the monitoring site Kosice, summer sampling. In this case, 2h cell exposure to EOM resulted in a slight but significant increase of oxidative DNA damage at three from total of six concentrations. The mean 8-oxodG values at these concentrations ranged from 15.3 to 26.1 per 10(6) nucleotides with a value 3.5 per 10(6) nucleotides in untreated cells. B[a]P, the positive control, induced a variable but insignificant increase of oxidative DNA damage in Hep G2 cell (approximately 1.6-fold increase over control value). Based on these data we believe that EOM samples extracted from airborne particle PM(10) play probably only a marginal role in oxidative stress generation and oxidative lesion formation to DNA. However, adsorbed organic compounds can undergo various interactions (additive or synergistic) with other PM components or physical factors (UV-A radiation) and in this way they might enhance/multiply the adverse health effects of air pollution.
Gábelová
Alena
A
Laboratory of Mutagenesis and Carcinogenesis, Cancer Research Institute of the Slovak Academy of Sciences, Bratislava, Slovakia. alena.gabelova@savba.sk
Valovicová
Zuzana
Z
Lábaj
Juraj
J
Bacová
Gabriela
G
Binková
Blanka
B
Farmer
Peter B
PB
D000080242:8-Hydroxy-2'-Deoxyguanosine; D000393:Air Pollutants / Q000633:toxicity*; D045744:Cell Line, Tumor; D020552:Comet Assay; D004249:DNA Damage; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000032:analysis; D006801:Humans; D009930:Organic Chemicals / Q000633:toxicity*; D010084:Oxidation-Reduction; D052638:Particulate Matter / Q000633:toxicity*
D000393:Air Pollutants; D009930:Organic Chemicals; D052638:Particulate Matter; D000080242:8-Hydroxy-2'-Deoxyguanosine; D003849:Deoxyguanosine