In vivo screening to determine neurological hazards of nitrogen dioxide (NO2) using Wistar rats

Abstract NO 2 is a well-known indoor and outdoor pollutant that may cause adverse health problems. Recently, accumulating but extremely limited evidences show that NO 2 possibly express neurotoxicity and is responsible for various neurological disorders. In the present study, neurological hazard of NO 2 and possible mechanisms were determined in rat pallium following a repetitive inhalation exposure with various concentrations (5, 10 and 20 mg/m 3 ). After 7-day exposure (6 h/day), observable adverse effects were induced encompassing decreased ratio of brain to body weight, mild brain pathology, increased neuronal apoptosis, altered antioxidants (Cu/Zn-SOD, Mn-SOD, GPx and NO) activity and increasing formation of PCO. NO 2 inhalation also induced augment of oncogenes (c-fos, c-jun) levels, and deregulation of apoptosis-related genes (p53, bax and bcl-2) expression. With all above data, the present report provided essential information for the characterization of the neurotoxic hazard of NO 2 and related mechanisms, which is required in response to the general concern about the vulnerability of the neurological system to it.