Toxicol Sci. 2010 Sep 23
Oxidative stress, inflammation and DNA damage in rats after intratracheal instillation or oral exposure to ambient air and wood smoke particulate matter.
Danielsen PH, Loft S, Jacobsen NR, Jensen KA, Autrup H, Ravanat JL, Wallin H, Møller P.
Section of Environmental Health, Department of Public Health, University of Copenhagen, Denmark.
Wood combustion is a significant source of ambient particulate matter (PM) in many regions of the World. Exposure occurs through inhalation or ingestion after deposition of wood smoke PM (WSPM) on crops and food. We investigated effects of ambient PM and WSPM by intragastric or intratracheal exposure in terms of oxidative stress, inflammation, genotoxicity and DNA repair after 24 hours in liver and lung tissue of rats. Rats were exposed to WSPM from high or low oxygen combustion and ambient PM collected in areas with and without many operating wood stoves or carbon black (CB) at the dose of 0.64 mg/kg bodyweight.
The levels of 8-oxo-7,8-dihydro-2′-deoxyguanosine, 1,N(6)-etheno-2′-deoxyadenosine and 1-N(2)-etheno-2′-deoxyguanosine (εdG) were significantly increased with 23% (95% CI: 0.1-45%), 54% (95% CI:18-90%) and 73% (95% CI: 31-134%) in the liver of rats exposed to CB, respectively. Rats orally exposed to PM from the wood stove area and low oxygen combustion WSPM (LOWS) had 35% (95% CI: 0.1-71%) and 45% (95% CI:
10-82%) increased levels of εdG in the liver, respectively. No significant differences were observed for bulky DNA adducts. Increased gene expression of proinflammatory cytokines, heme oxygenase-1 and oxoguanine DNA glycosylase 1 was observed in the liver following intragastric exposure and in the lung following instillation in particular of LOWS. Exposure to LOWS also increased the proportion of neutrophils in BAL fluid. These results indicate that WSPM and CB exert the strongest effect in terms of oxidative stress-induced response, inflammation, and genotoxicity in the organ closest to the port of entry.
