Inhaled nitric oxide improves the survival of the paraquat-injured rats

The purpose of this study was to evaluate the effects of inhaled nitric oxide (NO) on the paraquat-induced lung injury in rats. The rats were assigned to four groups: control; inhaled NO (5 ppm); paraquat (PQ, 30 mg/kg); and PQ+NO group. For first 18 h the inhalation of NO mixed with room air was performed. Total white blood cell (WBC), neutrophil, total protein, lactate dehydrogenase (LDH), transforming growth factor-beta 1 (TGF-beta 1) in serum and/or bronchoalveolar lavage (BAL) fluid, serum malonaldehyde (MDA), and myeloperoxidase (MPO) of lung were measured and lung histopathology were also reviewed. The 72-h survival rate of PQ group was 58%, but the survival rate of PQ+NO group, NO group and control group were 100%, respectively. The serum MDA and TGF-beta 1 in BAL fluid and blood of PQ+NO group were significantly lower than those of PQ group. However, inhaled NO did not decrease the elevated total WBC and neutrophil counts, and total protein, LDH and MPO activity in the lung injured by PQ. The alveolar septal thickening and inflammatory cell infiltration were not different between PQ and PQ+NO groups. NO inhalation may be beneficial for the survival of paraquat-induced injured rats by attenuating lipid peroxidation and production of TGF-beta 1. (c) 2005 Elsevier Inc. All rights reserved.