Roles of exogenous hydrogen sulfide in acute lung injury induced by lipopolysaccharide in aged rats

Aim:To explore the role of exogenous hydrogen sulfide(H2S) in lipopolysaccharide(LPS)-induced acute lung injury(ALI) in aged rats.Methods:Fourty-eight SD aged rats were randomized into three groups:control group,LPS group(instilled with LPS intratracheally to induce ALI),and NaHS+LPS group(injected NaHS abdominally before LPS instillation),and 16 in each group. Animals were sacrificed at 4 and 8 h after agent administration. Lung weight/body weight ratio(LW/BW) was calculated. Morphological changes of lung tissue were observed. The plasma levels of H2S,NO and CO were tested. Malondialdehyde(MDA) content,cystathionine-γ-lyase(CSE),inducible nitric oxide synthase(iNOS) and hemeoxygenase(HO) activity in lung tissue were determined. Immunohistochemistry technique was performed to examine the expression of iNOS and HO-1 protein in lung tissue.Results:Compared with those of the control group,IQA,LW/BW and MDA content in lung tissue of the LPS group were higher,the plasma levels of H2S and CSE activity in lung tissue were lower,the activity of iNOS and HO,the protein expression of them in lung tissue were higher,and the levels of NO and CO in plasma were higher(P0.05).The indexes mentioned above in NaHS+LPS group were improved compared with those in LPS group(P0.05).Conclusion:Downregulation of CSE/H2S is involved in the pathogenesis of ALI induced by LPS. Exogenous H2S may provide protection against the lung injuries to some extent,which may be explained by its anti-oxidative effects,the downregulation iNOS/NO system and the upregulation of HO-1/CO system.