Objective To investigate the effect of ginkgolide B(BN52021) on the NF-?B expression in pulmonary tissue of mice with LPS-induced acute lung injury.Methods Fifty Kunming mice were divided into 2 groups at random: LPS group(L group) and BN52021 pretreated group(B group),and then each group was subsequently divided into 5 subgroups according to different time point(0,1,3,9 and 12 h).The mice from corresponding groups received an intraperitoneal injection of normal saline or 20 mg/kg BN52021 followed by an injection of 15 mg/kg LPS 5 min later.The mice were sacrificed in 0,1,3,9 and 12 h after LPS injection.The wet/dry ratio(W/D) was recorded for pulmonary function and the pathological changes of lung tissues stained by HE were examined by light microscopy.The expression of NF-?B p65 was detected by Western blotting,and the levels of tumor necrosis factor-?(TNF-?) and interleukin-10(IL-10) were determined by ELISA.Results The significant increase of W/D was found after LPS injection in L group,which indicated the existence of pulmonary edema;while the W/D in B group was lower(P