Effects of Toll-like receptor 4 in lipopolysaccharide induced acute lung injury / 中华急诊医学杂志

ABSTRACT

Objective To observe the difference of lung injury between toll-like receptor 4 (TLR4) mutant mice and wild type mice in a model of lipopolysaccharide (LPS) induced acute lung injury (ALI),discuss the role of TLR4 in ALI.Methods Different doses of LPS solution (1,5mg?kg~(-1)) were injected in vein tail to reproduce ALI model in both TLR4 mutant (TLR4~(-/-)) and wild type (WT,TLR4~+(/+)) mice.Lung tissues were collected for gross and micrographic histological injury analysis and for assessment of lung edema.Meanwhile,the levels of myeloperoxidase (MPO) in lung tissues in both strains were assessed to evaluate the extent of polymorphological neutrophils (PMN) infiltration.Results The gross and micrographic injury of lung was milder in TLR4 mutant mice than that in wild type mice.The extent of lung edema (W/D) was also reduced compared with wild type mice,especially in 5 mg?kg~(-1) group [(4.08?0.1)vs.(4.55+0.2),n=10,t=12.71,P＜0.01].With high dosage of LPS,the value of W/D in both mice strains was higher than that in sham operation group (P＜0.01).The extent of PMN infiltration in lung tissues in TLR4 mutant mice was reduced compared with wild type mice.But they were higher than sham operated mice (P＜0.01).Conclusion TLR4 May involve in the development of ALI,by sequestration of PMN into lung tissues.