Abstract: AIM: To investigate the mechanisms and protective effects of recombinant human tumor necrosis factor receptor :Fc fusion protein (rhTNFR:Fc) on the acute lung injury induced by lipopo1ysaccharide (LPS)in rats.METHODS: The rat model of acute lung injury was established with LPS and the rats were randomly divided into four groups :control group, rhTNFR: Fc group, LPS group and rhTNFR:Fc +LPS group.After administration, the rats'death was recorded, the pulmonary wet dry weight ratios were determined, the changes of lung histopathology were observed by HE dyeing, the levels of TNF-αand the bioactivity in serumwere detected.RESULTS: Compared with control group the rats'mortality rate and pulmonary wet dry weight ratio were significantly higher in the LPS group (P <0.05).The pathological examination showed lung interstitial hyperemia, oedema, and generous inflammatory cell infiltrate.The levels of TNF-αand the bioactivity in serum increased significantly (P <0.05).The mortality rate decreased and the lung pathology injury obviously ameliorated in rhTNFR :Fc +LPS group.The TNF-αbioactivity in serum decreased significantly (P <0.05)compared with the LPS group.CONCLUSION: rhTNFR :Fc could degrade TNF-αbioactivity and abate the acute lung injury induced by LPS in rats by binding TNF-α.

Key words: lipopolysaccharide, acute lung injury, TNF-α, protection effects of rhTNFR:Fc