Protection Of Endogenous Carbon Monoxide To Lung And Kidney During Septic Shock And Elementary Discussing To Its Mechanism

Objective: Endotoxemia results from intestinalinfection is a kind of familiar pathological process. Itdevelops quickly and has many complications. It can involvemultiple organ or lead to multiple organ dysfunctionsyndrome(MODS) sometimes. Lung and kidney are ofteninvolved, mainly because endotoxin induces inflammationmediators to result in uncontrollable inflammation. Itsdetailed mechanism is unclear and oxidative injury isprobably one of the main mechanisms. Studies showed thatendogenous carbon monoxide(CO) could inhibit theproduction of inflammation mediator and alleviate theoxidative injury . However, whether CO can protect lung andkidney from injuries induced by cecal ligation andpuncture(CLP) deserves studying. In this study, septic shockwas induced by operation of CLP. Controlling the product ofCO by using the donor(Hemin) of heme oxygenase-1 (HO-1)and inhibitor(Zina protoporphyrin-â…¨,ZnPP) to regulate theactivity of HO-1, we evaluated the protective effect on lungand kidney of CO.Method: By using a Sprague-Dawley(SD) rat model of CLP,96 rats were randomly divide into four groups. â‘ the Sham group:only traversed a string at cecal root, did not ligate and puncture;â‘¡CLP group:treated by the operation of CLP;â‘¢CLP+Hemin(COdonor) group: Hm (10mg/kg, 10mg/ml, iv)was injected 10minbefore CLP operation; â‘£CLP+ZnPP(the specific HO-1inhibitor)group: ZnPP(10mg/kg, 10mg/ml, iv) was injected 10minbefore CLP operation. Parameter was observed respectively 2h, 4h,6h after CLP operation. Carpbxyhemoglbin (COHb) level inin-flowing pulmonary blood(IPB) and out-going pulmonaryblood(OPB) were detected. The level of COHb represented COcontent. The malondialdehyde(MDA) content and the activity ofsuperoxide dismutase(SOD) in blood,lung and kidney weredetected using test kits. The pathomorphological changes in thelung and kidney were observed under light microscope andimmunohistochemical technique were used to detect expression ofHO-1 protein in the lung and kidney after CLP. The results were asfollows:Level of COHb in OPB and IPB,content of MDA andactivity of SOD in blood,lung and kidney: Compared withSham group at corresponding time points, level of COHb inOPB,IPB and numerical value of (OPB-IPB) of CLP groupincreased significantly (P<0.05), and showed a tendency ofincreasing significantly with time (P<0.05). Activity of SODin blood,lung and kidney decreased significantly(P<0.05 or0.01), and showed a tendency of decreasing significantlywith time(P<0.05 or 0.01).While content of MDA in blood,lung and kidney increased significantly(P<0.05 or 0.01), andshowed a tendency of increasing with time;Compared withCLP group in corresponding time points, level of COHb inOPB ,IPB and numerical value of (OPB-IPB) ofCLP+Hemin group increased significantly(P<0.05),andshowed a tendency of increasing significantly withtime(P<0.05 or 0.01).Activity of SOD in blood,lung andkidney increased significantly (P<0.01), and showed atendency of increasing significantly with time(P<0.05 or0.01). While content of MDA in blood,lung and kidneydecreased significantly(P<0.05 or 0.01), and showed atendency of decreasing with time; Compared with CLPgroup in corresponding time points, level of COHb in OPB,IPB and numerical value of (OPB-IPB) of CLP+ZnPP groupdecreased significantly(P<0.05), and showed a tendency ofdecreasing with time. Activity of SOD in blood,lung andkidney decreased(P<0.05 or 0.01), and showed a tendency ofdecreasing with time. While content of MDA in blood,lungand kidney increased significantly(P<0.05 or 0.01), andshowed a tendency of decreasing significantly with time(P<0.05 or 0.01).The light microscope results showed that the destroiedstructure of alveolus, diffuse infiltration and migration ofacute inflammatory cells. Partition of alveolus wascongestive and dropsical. There were hyperemia,edema anddiffuse infiltration of acute inflammatory cells in glomerulus.And there was tumefaction and exfoliation on renal tubulesepithelium cells. Red blood cells could be seen in interstitialparts. The injuries in CLP+Hemin group at 2h,4h and 6hwere lighter than that of CLP group at corresponding timepoints. The injuries of CLP+ZnPP group at 2h,4h and 6hwas severer than CLP group on corresponding time.Immunohidtochemical studies showed:â‘ Lung: In Shamgroup, there was no brown positive signals of HO-1;in CLPgroup, Positive signals were obvious and mainly located incytoplasm of macarophage of alveoli,epithelial cells ofalveoli and airway,vascular smooth muscle cells; Positivesignals in CLP+Hemin group were more obvious than that ofCLP group; In CLP+ZnPP group, positive signals wereweaker than that of CLP group. â‘¡Kidney: In Sham group,there was mild brown positive signals of HO-1;The positivesignals in CLP group were more obvious than that of Shamgroup and mainly located in cytoplasm of endothelial cells ofcollecting tube,Henle's loops and glomerular capillary loops;The positive signals in CLP+Hemin group were moreobvious than that of CLP group, especially in glomerularcapillary loops and renal tubules. The signals in CLP+ZnPPgroup is weakened compared with CLP group atcorresponding time points, mainly in glomerular capillaryloops and renal tubules.Conclusion:â‘ CLP caused septic shock in rats andresulted in the acute injury of lung and kidney. The model of...