Abstract: Objective: To observe the effects of milrinone on the expression of TNF-α,IL-1β and IL-10 during acute lung injury(ALI) in rabbits.Methods: Eighteen rabbits were anesthetized with tracheotomy,and then ventilated mechanically.The animals were randomly allocated into three groups:group A(normal control,n=6),group B(endotoxin control,n=6) and group C(treatment group,n=6).Group B and C were induced into ALI by endotoxin.Group C were treated by intravenous milrinone at 5 μg·kg^-1·min^-1 after a bolus 50 μg/kg;group B and C received normal saline intravenously.The mean systemic arterial pressure(MAP) and mean pulmonary arterial pressure(mPAP) were recorded at the time of baseline(T1),after modeling 0(T2),and 120 min(T3).The levels of TNF-α,IL-1β and IL-10 in serum were detected,and arterial blood gas analysis was made at the same time.Polymorphonuclear neutrophils(PMN)(%) in bronchoalveolar lavage fluid(BALF) and lung wet-to-dry weight ratio(W/D)were determined after the animals were sacrificed.And lung specimens were obtained to observe the histological changes.Results: Compared with group B,the PaO₂ in group C increased and mPAP decreased significantly(P<0.01),and the ventilation function improved.After treatment,the concentrations of TNF-α and IL-1β in serum decreased significantly,while the concentrations of IL-10 in serum were significantly enhanced(P<0.01).And PMN(%) in the BALF decreased significantly(P<0.01).Conclusions: Milrinone could improve the pulmonary gas exchange and attenuate endotoxin-induced ALI.The mechanism of the effects may be that milrinone could regulate the imbalance between inflammatory and anti-inflammatory mediators by enhancing the generation of IL-10 and refraining the release of IL-1β and TNF-α.