| Objective: Hepatic cirrhosis is a chronic, progressive and diffuse hepatic lesions resulted from chronic injury of hepatocytes by many factors. Portal hypertension is one of the main clinical manifestations in decompensative stage of cirrhosis and can cause many complications, such as hepatorenal syndrome and hepatopulmonary syndrome, which can increase the motality of those patients. Carbon monoxide （CO） is a byproduct of Heme oxygenase-1 （HO-1） which shares many characteristics with NO. As a vasodilator, CO may also participate in the pathogenesis of portal hypertension, hepatorenal syndrome and hepatopulmonary syndrome. Our previous studies show that expression of HO-1 increases significantly in immune hepatic fibrotic rat models, which have a protective effect on liver.In this study, our first objective was to evaluate the expression of HO-1 in liver, kidney and lung of experimental rats with cirrhosis. Our second objective was to evaluate the effects of HO-1 on these organs by manipulating its activity via intraperitoneal injection of either zinc protoporphyrin IX （ZnPP）, a specific HO-1 enzyme inhibitor, or cobalt protoporphyrin （CoPP）, a specific HO-1 enzyme inducer.Methods: Rats were divided into liver cirrhosis, ZnPP, CoPP and sham groups. Biliary cirrhosis was established by bile duct ligation in the first three groups. Rats in the ZnPP and CoPP groups received once intraperitoneal injection of ZnPP and CoPP, respectively, 24 hours before sample collection. The expression of HO-1 mRNA was measured by reverse-transcription polymerase chain reaction, while protein expression was determined by immunohistochemical analysis and Western-blot. Hematoxylin and eosin staining was performed to observe liver cirrhosis, renal and pulmonary structure. Renal artery blood flow, mean arterial pressure （MAP） and portal vein pressure （PVP）, 24-hour total urinary volume, serum and urine sodium concentrations, serum aspartate aminotransferase （AST）, arterial blood gas analysis and creatinine clearance rate （Ccr） Results:1.The Modeling of the liver cirrhosis in rats（1） The serum levels of AST in the biliary cirrhotic group were 209.11±45.77 IU/L, which were significantly higher than those in the sham group （156.8±18.28 IU/L, P < 0.05）;（2） The PVP was significantly higher in the cirrhotic group than in the sham group（15.56±2.36 mmHg vs 9.24±0.76 mmHg, P﹤0.01）;（3） The MAP was significantly lower in the cirrhotic group than in the sham group（59.23±12.19 mmHg vs 118.83±8.09 mmHg, P﹤0.01）;（4） By HE staining, in the livers of 4 weeks rats after BDL, we observed bridging necrosis of hepatic cells particularly in portal areas, nodular regeneration of hepatocytes, collapse, and disorganization of the hepatic lobular structure, numerous lymphocytes infiltrating the portal area and around the central vein, and the formation of pseudolobules surrounded by fibrous septa.2. The expression and significence of hepatic heme oxygenase-1 in cirrhotic rats（1） Western-blot and immunohistochemical detection showed that the expression of hepatic HO-1 protein was higher in the cirrhotic group than that in the sham group; As determined by RT-PCR, the hepatic expression level of HO-1 mRNA in the cirrhotic group was significantly higher than that in the sham group （P < 0.05）. The serum levels of AST in the biliary cirrhotic group were significantly higher than those in the sham group;（2） Compared with the cirrhotic group, the expression of hepatic HO-1 protein was decreased in the ZnPP group by Western-blot and immunohistochemical detection, and the expression of hepatic HO-1 mRNA in the ZnPP group was significantly lower than that in the cirrhotic group by RT-PCR detection（P < 0.05）; Compared with the cirrhotic group, the serum levels of AST and carboxyhemoglobin （COHb） were lower,the number of lymphocytes infiltrating the portal area and around the central vein was smaller in the ZnPP group;（3） Compared with the cirrhotic group, the expression of hepatic HO-1 protein was increased in the CoPP group by Western-blot and immunohistochemical detection, and the expression of hepatic HO-1 mRNA in the CoPP group was significantly higher than that in the cirrhotic group by RT-PCR detection（P < 0.05）; Compared with the cirrhotic group, the serum levels of AST and COHb were higher, the number of lymphocytes infiltrating the portal area and around the central vein was larger in the CoPP group.3. The expression and significence of renal heme oxygenase-1 in cirrhotic rats（1） Western-blot and immunohistochemical detection showed that the expression of renal HO-1 protein was lower in the cirrhotic group than that in the sham group; As determined by RT-PCR, the renal expression level of HO-1 mRNA in the cirrhotic group was significantly lower than that in the sham group （P < 0.05）. Compared with the sham group, the renal artery blood flow,the 24-hour urine volume, the serum sodium concentration and Ccr were significantly lower in the cirrhotic group;（2） Compared with the cirrhotic group, the expression of renal HO-1 was decreased in the ZnPP group （P < 0.05）; Compared with the cirrhotic group, the renal artery blood flow, the 24-hour urine volume, the serum sodium concentration and Ccr were significantly lower（P﹤0.05）in the ZnPP group; the PVP and the MAP were not significantly affected by treatment with ZnPP;（3） Compared with the cirrhotic group, the expression of renal HO-1 was significantly increased in the CoPP group （P < 0.05）; Compared with the cirrhotic group, renal artery blood flow, the 24-hour urine volume,the serum sodium concentration（P﹤0.05）and Ccr were increased（P> 0.05）in the CoPP group; the PVP and the MAP were not significantly affected by treatment with CoPP.4. The expression and significence of pulmonary heme oxygenase-1 in cirrhotic rats（1） Western-blot and immunohistochemical detection showed that the expression of pulmonary HO-1 protein was higher in the cirrhotic group than that in the sham group; As determined by RT-PCR, the pulmonary expression level of HO-1 mRNA in the cirrhotic group was significantly higher than that in the sham group （P < 0.05）. Compared with the sham group, the level of arterial COHb, alveolar-arterial oxygen gradient （A-aPO2） （P < 0.05） and intrapulmonary vasodilation were also significantly increased in the cirrhotic group;（2） Compared with the cirrhotic group, the expression of pulmonary HO-1 was decreased in the ZnPP group （P < 0.05）; Compared with the cirrhotic group, the level of COHb, A-aPO2 （P < 0.05） and intrapulmonary vasodilation were significantly decreased in the ZnPP group;（3） Compared with the cirrhotic group, the expression of pulmonary HO-1 was significantly increased in the CoPP group （P < 0.05）; Compared with the cirrhotic group,the level of COHb, A-aPO2 （P < 0.05） and intrapulmonary vasodilation were significantly increased in the CoPP group.Conclusion: 1. Models of liver cirrhosis, hepatorenal syndrome and hepatorenal syndrome in rats can be established by bile duct ligation.2. In the stage of portal hypertension, the expressions of HO-1 are different in different tissues. It increases in liver and lung, and decreases in kidney.3. The over-expression of HO-1 in liver of cirrhotic rats has a damaging effect.4. Decreased HO-1 expression in the kidney plays an important role in the pathogenesis of experimental HRS.5. Increased pulmonary heme oxygenase-1 expression is an important contributor to the development of experimental hepatopulmonary syndrome. |
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