Effects of exogenous hydrogen sulfide on acute lung injury during hemorrhagic shock and resuscitation in rats

Abstract

Objective To evaluate the effects of exogenous hydrogen sulfide on acute lung injury during hemorrhagic shock and resuscitation (HS/R) in rats.Methods Thirty-two SPF adult male rats,weighing 250-300 g,aged 6-8 weeks,were randomly divided into 4 groups (n =8 each) using a random number table:sham operation group (S group),sham operation + exogenous NaHS group (S + NaHS group),HS/R group and HS/R + NaHS group.HS/R was induced by withdrawing blood from the femoral artery for 10 min.The mean arterial pressure was maintained at 35-40 mmHg for 90 min.The animals were then resuscitated for 60 min with infusion of lactated Ringer's solution 3 times the volume of blood withdrawn and shed blood.NaHS 28μmol/kg was injected intraperitoneally before resuscitation in HS/R + NaHS and S + NaHS groups.At 3 h after the end of resuscitation,the lungs were harvested and bronchoalveolar lavage fluid (BALF) was prepared for determination of protein,IL-6 and TNF-α concentrations.Lungs were removed for examination of pathological changes which were scored and for determination of wet to dry lung weight (W/D) ratio,myeloperoxidase (MPO) activity,cell apoptosis,and expression of caspase-3,caspase-8,Bcl-2,Bax and BH3 interacting-domain death agonist (BID).Results Compared with S group,the protein,IL-6 and TNF-α concentrations in BALF,pathological score,W/D ratio,MPO activity,and the number of apoptotic cells were significantly increased,the expression of caspase-3,caspase-8,Bax and BID was up-regulated,and the expression of Bcl-2 was down-regulated in HS/R and HS/R + NaHS groups,and no significant changes were found in the parameters mentioned above in S + NaHS group.Compared with HS/R group,the protein,IL-6 and TNF-α concentrations in BALF,pathological score,W/D ratio,MPO activity,and the number of apoptotic cells were significantly decreased,the expression of caspase-3,caspase-8,Bax and BID was down-regulated,and the expression of Bcl-2 was up-regulated in HS/R + NaHS group.Conclusion Exogenous hydrogen sulfide can alleviate acute lung injury during HS/R in rats and inhibition of inflammatory responses and cell apoptosis is involved in the mechanism. Key words: Hydrogen sulfide ; Shock, hemorrhagic ; Respiratory distress syndrome, adult