Abstract: ObjectiveTo study the effect of lycopene on the function of pulmonary alveolar macrophages(PAMs)of rat's acute lung injury(ALI).MethodMale rats were gavaged continuously by lycopene with 0.5,1.0,3.0 mg/kg for 30 days;Lipopolysaccharide was used to make the model of ALI rats.After 1 hour,4 and 6 hours,bronchoalveolar lavage was done,and the function of PAMs,the amount of PAMs and the lung relative weight were determined.ResultsLycopene could increase the phagocytic function of PAMs significantly.Compared with the model group,the phagocytic function of PAMs was increased significantly in lycopene groups,with increasing rates of 11.2%,27.9%,38.1% after injection of L PS for 1 hour,with increasing rates of 5.9%,4.4%,17.0% after injection of LPS for 4 hours,and with increasing rates of 16.6%,15.2%,21.9% after injection of LPS for 6 hours,respectivelely compared with the model group.The phagocytic function of PAMs was increased obviously by three different dose of lycopene,showing a dose-response relationship(P<0.05).ConclusionLycopene,at the dose of 0.5,1.0 and 3.0 mg/kg,could reinforce the phagocytic function of PAMs.