| Object: NO and CO are two important gaseous messenger mediators that are supposed to be involved in the formation of portal hypertension and hyperdynamic circulation of liver cirrhosis. In vivo they were independently synthesized under the catalysis of nitric oxide synthase (NOS) and heme oxygenase (HO). In this study, the changes of NOS-NO and HO-CO Systems in different stages of rat model of liver cirrhosis were investigated. Their effects on the formation of portal hypertension were discussed. Methods: Rat model of liver cirrhosis was induced by CC14 plus ethanol method (40% CC14 3 ml/kg subcutaneously injected once every 5 days, double in the first dosage; 30% ethanol was the only drink; corn flour and lard were fed) Blood and liver tissues were sampled from rats in different stages of liver cirrhosis. They were histologically divided into the early stage group (day 15 after CC14 administration, N=13); the mid-stage group (day 30 after CC14 administration, N=ll), and the late stage group (day 52 after CC14 administration, N=ll). Samples from 10 normal rats were similarly collected as control. Blood samples were taken from portal vein and the inferior vena cava. The concentrations of CO and NO in the plasma were determined with nitrate reductase and chemical methods, respectively. Part of the liver tissues was embedded and fixed for immunohistochemical analysis of the distribution of iNOS, HO-1 and HO-2 proteins in the livers. The slides were then analyzed with an Image Analyzing system to obtain the integral light concentration (ILD) of stained proteins. The lower ILD of stained proteins was, the stronger expression of proteins was. Another part of the liver tissues was collected for the determination of the mRNA expressions of iNOS and HO-1, HO-2. Total RNA was extracted with one-step TRIZOL method and theexpression of iNOS and HO-lmRNA, HO-2mRNA in the liver samples was semi-quantitatively assayed with RT-PCR. The mRNA expression of GAPDH was also detected and used as an internal control. CDS 800 gel imaging system was used for the semi-quantitative analysis of the mRNA expressions. The results were expressed as the ratio (R) of the densities of the expression bands of iNOS, HO-1 with that of GAPDH.Results: NO concentrations in the inferior vena cava of rats in the normal control group, the early stage, the mid-stage, and the late stage group were 71. 088 8. 739,102. 821 6. 783, 122. 499 4. 605, 155. 843 10. 328 ml/L, respectively. The values in the early stage, the mid-stage, and the late stage group were significantly higher than that in the normal control group.NO concentrations in the portal vein of rats in the normal control group, the early stage, the mid-stage, and the late stage group were 87. 025 7. 858, 115.377 7.935, 146.222 8.360, 182.811 8.449 mol/L, respectively. The values in the early stage, the mid-stage, and the later stage group were significantly higher than that in the normal control group.The NO concentrations in the portal vein of normal and liver cirrhosis groups were significantly higher than that in the inferior vena cava.iNOS was expressed mainly in the hepatocytes in the normal livers and livers at different stages of liver cirrhosis. Small amount of sinusoidal cells and Kupffer cells were also shown positive staining. The ILD of the stained iNOS protein in the liver tissues of the normal control group, the early stage, the mid-stage, and the late stage group were 157.30 2.71, 127.62 17.30, 117.73 16. 40 and 108.00 10.68, respectively. The ILD values of iNOS in the early stage, the mid-stage, and the late stage groups of liver cirrhosis were significantly different as compared to that in the normal control group.The R ratios of iNOSmRNA expression in the livers of rats in the normal control group, the early stage, the mid-stage, and the late stage group were 0. 3024 0. 00449, 0. 4384 0. 00582, 0. 7584 0. 00759, 0. 8810 0. 00729, respectively. The ratios in different stages of liver cirrhosis groups were significantly higher than that in the normal...
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