Acute lung injury (ALI) and its more severe form acute respiratory distress syndrome (ARDS) are acute clinical complications,which cause significant morbidity and mortality.1 Despite recent advances in our understanding of the pathophysiology and diagnosis of ALI and ARDS,the clinical strategies are restricted to mechanical ventilation and supportive treatments,such as fluid conservative management and glucocorticoids (GCs).Mechanical ventilation is a common and life-saving strategy for the patients with ARDS.Lung protective ventilation strategy with lower tidal volumes can improve hypoxia and reduce the mortality in patients with ARDS.