Objective To evaluate the effect of deferoxamine on ventilator-associated lung injury in rats.Methods Twenty-four healthy male Sprague-Dawley rats,aged 6-8 weeks,weighing 250-300 g,were divided into 3 groups (n =8 each) using a random number table method:control group (group C),ventilator-associated lung injury group (group VALI),and ventilator-associated lung injury plus deferoxamine group (VALI+DFO group).Normal saline 2 ml was intraperitoneally injected in C and VALI groups,and deferoxamine 200 mg/kg (dissolved in 2 ml normal saline) was intraperitoneally injected in group VALI+DFO.The animals were connected to a small animal ventilator 15 min later and mechanically ventilated in volume-controlled mode,with tidal volume 40 ml/kg,respiratory rate 40-60 breaths/min,inspiratory/expiratory ratio 1 ∶ 1,and inspired oxygen fraction ratio 1.0.The rats were sacrificed after the end of mechanical ventilation,and the left lung tissues were removed for examination of the pathological changes (with a light microscope) which were scored and for determination of wet/dry weight ratio (W/D ratio).The right lung was lavaged,and lavage fluid was collected to prepare macrophage suspension,and the alveolar macrophage and mitochondrial reactive oxygen species (ROS) levels were determined using flow cytometry.Results Compared with group C,the pathological score,W/D ratio of lung tissues,and alveolar macrophage and mitochondrial ROS levels were significantly increased in group VALI,and the pathological score was significantly increased in group VALI (P＜0.05).Compared with group VALI,the pathological score,W/D ratio of lung tissues,and alveolar macrophage and mitochondrial ROS levels were significantly decreased in group VALI and DFO (P＜0.05).Conclusion Deferoxamine can reduce ventilator-associated lung injury,and the mechanism may be related to inhibiting oxidative stress in rats.