Effect of H2S on apoptosis of lung tissue attacked by lipopolysaccharide and lung protection mechanism

Objective To observe the effect of hydrogen sulfide(H2S) on apoptosis of lung tissue in lipopolysaccharide(LPS)-induced acute lung injury(ALI) in rats.Methods 140 Sprague-Dawley rats were randomly divided into four groups:sham-operated group,model group(LPS was instilled intratracheally to induce ALI),LPS+NaHS(H2S donor) group,and LPS+PPG(propargylglycin,CSE inhibitor) group.Seven rats of each group,right heart catheter method was used to monitor and record MPAP before agent administration and 2,4,6 and 8 hours after agent administration.Twenty-eight rats were sacrificed at 4 h(14 rats) or 8 h(14 rats) after agent administration.Protein expression of Bcl-2 and Fas were detected by immunohistochemical method.Lung histomorphological changes were observed under microscope and index of quantitative assessment(IQA) was calculated to measure the lung injury severity.Results Compared with sham-operated group,severe injuries of lung tissues and raised IQA,MPAP in each time,higher expression of Fas protein,lower expression of Bcl-2 protein were observed in rats treated with LPS(all P0.01).Pre-administration of NaSH not only alleviated the injuries induced by LPS,but increased expression of Bcl-2 protein,decreased IQA,MPAP in each time and expression of Fas protein.Pre-administration of PPG exacerbated the injuries induced by LPS(all P0.01).Also,decreased expression of Bcl-2 protein,increased IQA,MPAP in each time and expression of Fas protein were observed(all P0.01).Conclusion H2S can protect lung tissue of ALI rats by alleviating apoptosis of lung tissue attacked by LPS.