Protective effects of N-acetylcysteine on ventilator-induced lung injury in rat models

Objective To explore the protective effects of N-acetylcysteine on ventilator-induced lung injury( VILDin rat models. Methods 30 healthy male Sprague-Dawley rats were randomly divided into three groups. After anesthesia was administered and tracheotomy was performed,rats received ventilation of two different tidal volume for 4 hrs: group A was served as control groups (n - 10, VT = 8 ml/ kg), group B received large tidal volume ventilation ( n = 10, VT = 40 ml/kg), group C( n = 10) received the same tidal volume as group B with pre-treatment of N-acetylcysteine. Arterial blood gases were measured every one hour. Total white blood cells (WBCs) and neutrophils in BALF were counted. Wet to dry weight ratio (W/D) of right lung, the concentrations of total protein in bronchoalveolar lavage fluid (BALF) ,TNF-α and IL-1β levels in BALF and blood,malondialdehyde(MDA) and superoxide dismu-tase (SOD)levels in the lung and blood were assayed,respectively. Lung histopathology was assessed and compared among three groups. Results After mechanical ventilation for 4 hrs, arterial oxygen pressure (PaO2) was significantly lower in group B than that in group A and C. A large quantity of neutrophils were found in BALF of group B. The total protein contents in BALF and W/D of right lung were significantly higher in group B than those in group A and C. The levels of TNF-α and IL-1β in BALF were increased in group B[(0.53±0.09)ng/L,(0.092 0±0.012 4)(tg/L],while decreased in group C [(0.25 ±0.04)μg/L,(0.046 5 ±0.007 5)μg/L]. MDA levels in the lung and blood were decreased in group C than those in group B, but the levels of SOD was significantly higher in group C than those in group B. Histopathologic findings demonstrated more infiltrating neutrophils, destructive change of the alveolar wall in group B compared to other groups.Conclusions Proinflammatory and inflammatory reactions and the imbalanced oxidative/antioxidative reactions may be involved in the pathogenesis of VILI. N-acetyl-cysteine has definite protective effects on VILI through its anti-inflammation/antioxidant potency.