ObjectiveTo investigate the effect of aerosolized pulmonary surfactant (PS) on the blood oxygenation in rats with acute lung injury(ALI). MethodsFortythree SD rats were randomly divided into 4 groups: sham group (operated only, n=10), model group(n=10), airNS group (inhaling aerosolized normal saline, n=10), and airPS group (inhaling aerosolized PS\[160 mg\], n=13). ALI rats were induced by oleic acid(0.2 ml/kg) through jugular vein. The arterial blood gas and breathing rates were determined during the experiment in all groups. The survival rates of all groups were determined after experiments. ResultsPS aerosolization led to a gradual increase of PaO2 and SaO2. Four hours after inhalation of aerosolized PS, the PaO2 and SaO2 increased to 99.4 mmHg(1 mmHg=0.133 kPa) and 98.2%, respectively, which were significantly higher than those in the airNS group (P<0.05). The breathing rate began to decease 0.5 h after inhalation of aerosolized PS and decreased to 100 breaths/min 4 h later, which was significantly lower than that in the airNS group at the same time point (P<0.05). The survival rate of animals in the airPS group was 100%, also significantly higher than that in the airNS group (60%, P<0.05). ConclusionAerosolized PS through spontaneous breathing can improve the blood oxygenation, pulmonary function and survival rates of ALI rats.