AIM: To explore the molecular mechanism of brain tissue injury induced by lipopolysaccharide(LPS),the effects of panaxadiol(PDS) on the expression of nuclear factor kappa B(NF-?B) in cerebral cortex of rat with LPS shock were studied.METHODS: Rats were randomly divided into LPS group,LPS+dexamethasone group,LPS+PDS group and control group.The DNA binding activity and protein expression of NF-?B were observed.These indices were assayed at 1 h and 4 h after intravenous injection of LPS(4 mg?kg-1).RESULTS: EMSA showed that PDS inhibited NF-?B DNA-binding activity in nuclear extracts at both 1 h and 4 h after LPS injection,compared with the LPS group(P