Effects of melittin on acute lung injury in mice based on TLR4/NF-κB signaling pathway
AIM:To explore the protective effect and mechanism of melittin against LPS induced acute lung injury.METHODS:Mice were intratrache-ally injected with LPS(5 mg/kg)to establish acute lung injury model.The lung coefficient of mice and the lung wet-dry mass ratio were determined.The lung tissue was stained with HE.The number of in-flammatory cells and expression levels of related in-flammatory factors in bronchoalveolar lavage fluid(BALF)were detected.The activities of serum SOD,MDA and GSH were detected.The expression of TLR4,NF-κB p65 and p-NF-κB p65 in lung tissues were determined by immunohistochemistry and Western blot.RESULTS:Melittin had a protective ef-fect on LPS-induced ALI,as evidenced by significant-ly reduced lung coefficient,lung wet/dry mass ra-tio,the number of inflammatory cells and the ex-pression level of inflammatory factors in BALF,and improved pulmonary pathology(P<0.05,P<0.01).Compared with model group,the serum MDA level of melittin group was significantly decreased(P<0.01),while the activities of SOD and GSH were sig-nificantly increased(P<0.05,P<0.01).In addition,melittin can significantly reduce the expression of TLR4,inhibit the phosphorylation of NF-κB p65,and reduce the inflammatory response(P<0.01).CONCLUSION:Melittin can significantly improve LPS-induced ALI,and the protective effect of melit-tin is mainly related to the inhibition of TLR4/NF-κB signaling pathway and the reduction of oxidative stress and inflammation.