ObjectiveTo study the effects of hydroxysafflow yellow A (HSYA) in inhibiting inflammatory signal transduction in lungs of acute lung injury mice induced by lipopolysaccharide (LPS). MethodsEighty-four male Kunming mice were randomly divided into 7 groups, ie. a sham group, a LPS group, a LPS+3 mg/kg dexamethason (DXM) group, a LPS+6 mg/kg HSYA group, a LPS+15 mg/kg HSYA group, a LPS+37.5 mg/kg HSYA group, and a saline+37.5 mg/kg HSYA group (n=12 in each group). The mice were intraperitoneally pretreated with normal saline or DXM or HSYA 0.5 hour prior to intravenous adminstration of LPS. TNF-α, IL-1β and IL-6 levels in mice serum were measured by ELISA and the mRNA and protein levels of TLR4 in mice lungs were assessed by RT-qPCR and Western blot, respectively. ResultsAfter being treated with HSYA in doses of 6 mg/kg, 15 mg/kg, and 37.5 mg/kg, the increased expression levels of TLR4 mRNA and protein induced by LPS were significantly inhibited, as well as the increased expression levels of TNF-α, IL-1β and IL-6. The inhibitoty effect enhanced with the doses of HSYA. DXM could inhibit more significantly the increased expression levels of all the indexes. ConclusionHSYA can inhibit inflammatory signal transduction in acute lung injury mice induced by LPS in a dose-dependent manner, but is less effective than DXM.