RESUMO
Objective To investigate the role of Toll?like receptor 4(TLR4)in acute lung injury induced by paraquat(PQ)poisoning. Meth?ods Twenty wild?type mice(C57BL/6J)and TLR4 knockout mice(C57BL/10ScN)were randomly divided into 4 groups:WT group,WT+PQ group,TLR4 gene knockout(TLR4?ko)group and TLR4?ko+PQ group,with 10 mice in each group. After paraquat treatment for 24 hours,mice were euthanized and sacrificed. TLR4 expression and pro?inflammatory cytokines were evaluated. Results After 24 hours of intraperitoneal injec?tion of PQ,wild?type mice showed significant acute lung injury,including decreased oxygen tension in blood gas,pathological changes in the acute stage of lung injury and increased TLR4 expression(accompanied by increased levels of TNF?α,IL?1βand NF). TLR4?deficient mice exhibited significantly reduced level of paraquat?induced lung injury. Conclusion TLR4 may be required as a mediator and play an important role in acute lung injury induced by paraquat. Inhibition of TLR4 signaling has protection of lung injury induced by PQ.