<正>Objective:To explore the role of activated liver X receptor a （LXRα） on the expressions of interleukin-1 receptor associated kinase-4 （IRAK-4） and NF-kappaB （NF-κB） in the inflammatory response which induced by LPS in the Kupffer cells and to investigate the possible mechanisms of LXRαnegative regulation of inflammatory response. Methods:The Kupffer cells were isolated from male Kunming mice by collagen perfusion in situ.And these cells were divided into 4 groups:normal control group

LPS treatment group

LXRαagonist T0901317 treatment group

LPS and T0901317 combined treatment group.The LPS treatment group were treated with a final concentration of 1μg/ml LPS in RPMI 1640 and cultured for 6 h

the T0901317 treatment group were treated with a final concentration of 5μg/ml in RPMI 1640 and cultured for 24 h

and the combined treatment group received pre-culture for 24 h with a final concentration of 1μg/ml T0901317 in RPMI 1640 and then cultured for 6 h with a final concentration of 5μg/ml LPS in RPM! 1640.All groups were cultured for 30 h.The expression of LXRα

IRAK-4 and NF-κB at mRNA and protein levels were detected by real-time PCR and Western blotting

and the TNF-αand IL-1βlevels were detected by ELISA. Results:The levels of LXRαmRNA and protein were highest in T0901317 group

and lowest in LPS group （P<0.05）. The level of IRAK4 and NF-κB mRNAs and proteins were evidently lower in the Combined-treated group than in LPS group （P<0.05）.And the level of TNF-αand IL-1 were observed highest in LPS group （P<0.05）

but no difference among the Control group

T0901317 group and Combined-treated group （P>0.05）.Conclusion:These date suggest that the LXR agonists can effectively up-regulate the expressions of LXRαmRNA and protein and inhibit the inflammatory response.This may be via down-regulating the expressions of IRAK4 and NF-κB at mRNA and protein levels.