Vascular and Cardiac Impairments in Rats Inhaling Ozone and Diesel Exhaust Particles

BackgroundMechanisms of cardiovascular injuries from exposure to gas and particulate air pollutants are unknown.ObjectiveWe sought to determine whether episodic exposure of rats to ozone or diesel exhaust particles (DEP) causes differential cardiovascular impairments that are exacerbated by ozone plus DEP.Methods and resultsMale Wistar Kyoto rats (10–12 weeks of age) were exposed to air, ozone (0.4 ppm), DEP (2.1 mg/m3), or ozone (0.38 ppm) + DEP (2.2 mg/m3) for 5 hr/day, 1 day/week for 16 weeks, or to air, ozone (0.51 or 1.0 ppm), or DEP (1.9 mg/m3) for 5 hr/day for 2 days. At the end of each exposure period, we examined pulmonary and cardiovascular biomarkers of injury. In the 16-week study, we observed mild pulmonary pathology in the ozone, DEP, and ozone + DEP exposure groups, a slight decrease in circulating lymphocytes in the ozone and DEP groups, and decreased platelets in the DEP group. After 16 weeks of exposure, mRNA biomarkers of oxidative stress (hemeoxygenase-1), thrombosis (tissue factor, pl...