Subchronic exposure to ambient particulate matter induces oxidative stress responses in brain tissue of ApoE -/- mice

Conclusions CAPs or particle-free air for 5 hours a day, 5 days per week, for a period of 6 months. The whole-body inhalation exposures were conducted in two urban cities (Seattle, WA and Detroit, MI) with distinct sources and chemical composition of PM. Brain tissue was collected after the exposures were completed and analyzed for biomarkers of oxidative stress. The antioxidant glutathione (GSH) was reduced in the brains of mice exposed to CAPs in Michigan but not in Washington. In contrast the lipid peroxidation product 4-hydroxyalkenal (HNE) was significantly increased in the membrane fraction of brain tissue of mice exposed to CAPs in Washington but not in Michigan. No significant differences were observed in protein carbonyl levels, a biomarker of protein oxidation, although the levels were slightly higher in the cytoplasmic fraction of brain tissue from animals exposed to CAPs when compared to controls regardless of exposure site. The results suggest that PM from different sources can modulate oxidative stress responses in a distinct fashion and that different subcellular fractions in the brain can be more susceptible to the effects of PM. • Total GSH levels were reduced in brain samples of mice exposed to