Oxidative stress, endothelial dysfunction and inflammatory response in rat heart to NO2 inhalation exposure

Epidemiological studies suggest that NO2 inhalation is associated with adverse effects on heart-related health, however, existing experimental data lack relevant evidences. In this study, a role for oxidative stress, endothelial dysfunction and inflammatory responses in the heart of rats treated with different concentrations of NO2 (0, 5, 10 and 20 mg m(-3)) was investigated. Mild heart pathology occurred after 7-d exposure (6 h d(-1)). Marked oxidative stress were induced as evaluated by reduction/induction of antioxidants (Cu/Zn-SOD, Mn-SOD and GPx) activity and increasing formation of MDA and PCO. Also, mRNA and protein biomarkers of vasoconstriction (ET-1, eNOS) and inflammation (INF-alpha, IL-1 beta and ICAM-1) were up-regulated, and p53 mRNA expression, bax/bcl-2 ratio and the mean number of TUNEL-positive myocytes were increased as well. All the results implicate that NO2 exerted injuries to mammals' heart, and the damage mechanisms were possibly associated with oxidative stress, endothelial dysfunction and inflammation. (C) 2010 Elsevier Ltd. All rights reserved.