[Observation on experimental liver fibrosis and hepatic carcinogenesis of HBV gene knock-in transgenic mice induced by CCl4/ethanol].

OBJECTIVE: To study the effects of carbon tetrachloride (CCl4)/ethanol induction upon experimental liver fibrosis and hepatic carcinogenesis of HBV transgenic mice. METHODS: The wild-type mice, p21-HBx transgenic mice with integration of p21 locus by HBx gene and p21-HBsAg transgenic mice with integration of p21 locus by HBsAg gene were induced separately by CCl4/ethanol twice weekly for 20 weeks. The investigators observed the development of liver fibrosis and hepatic carcinogenesis in three groups and detected the gene expressions of HBx and HBsAg by RT-PCR. RESULTS: The expression of HBx or HBsAg mRNA existed in both control and induced transgenic mice, but in none of wild-type mice. Comparing with wild-type mice, p21 genes was not expressed in livers of transgenic mice. After induction by CCl4/ethanol, the fibrotic degrees of liver were not significantly different among wild-type mice, p21-HBx transgenic mice and p21-HBsAg transgenic mice, as well as between male and female mice. Reversely, the incidence rates of hepatic carcinogenesis of two HBV gene knock-in transgenic mouse lines (p21-HBx & p21-HBsAg) were higher than that of wild-type mice. And the incidence rate of hepatic carcinogenesis in males was also markedly higher than that in females. Induction by CCl4/ethanol markedly promoted and accelerated hepatic carcinogenesis in transgenic mice. CONCLUSIONS: Integration of HBsAg and HBx genes into the murine p21 locus can significantly promote the progression of hepatic carcinogenesis, but failed to promote the progression of liver fibrosis. The male mouse is more likely to develop experimental hepatocellular carcinoma than the female mouse. Experimental hepatocellular carcinoma induced by CCl4/ethanol in p21-HBx and p21-HBsAg transgenic mice is a feasible animal model.

Effect of hepato-toxins in the acceleration of hepatic fibrosis in hepatitis B mice.

Chronic liver diseases such as hepatitis B viral (HBV) infection and liver fibrosis have been a major health problem worldwide. However, less research has been conducted owing to the lack of animal models. The key purpose of this study was to determine the effects of different hepatotoxins in HBV-affected liver. In this study, we successfully generated a combined liver fibrosis model by administering HBV 1.2 plasmid and thioacetamide/ethanol (TAA/EtOH). To our knowledge, this is the first study in which an increase in the liver fibrosis level is observed by the intraperitoneal administration of TAA and EtOH in drinking water after the hydrodynamic transfection of the HBV 1.2 plasmid in C3H/HeN mice. The HBV+TAA/EtOH group exhibited higher level of hepatic fibrosis than that of the control groups. The hepatic stellate cell activation in the TAA- and EtOH-administered groups was demonstrated by the elevation in the level of fibrotic markers. In addition, high levels of collagen content and histopathological results were also used to confirm the prominent fibrotic levels. We established a novel HBV mice model by hydrodynamic injection-based HBV transfection in C3H/HeN mice. C3H/HeN mice were reported to have a higher HBV persistence level than that of the C57BL/6 mouse model. All the results showed an increased fibrosis level in the HBV mice treated with TAA and EtOH; hence, this model would be useful to understand the effect of hepatotoxins on the high risk of fibrosis after HBV infection. The acceleration of liver fibrosis can occur with prolonged administration as well as the high dosage of hepatotoxins in mice.

Newcastle disease virus represses the activation of human hepatic stellate cells and reverses the development of hepatic fibrosis in mice.

BACKGROUND/AIMS: Activated hepatic stellate cells (HSCs) are the crucial factor responsible for liver fibrosis and involved in development of hepatocellular carcinoma (HCC) by interaction with tumour cells. Newcastle disease virus (NDV) has the oncolytic characteristics of intrinsically selective replication in neoplasia cells and transformed cells. But, NDV replication in HSCs and effects on hepatic fibrosis have not been reported. METHODS: We detected the effect of conditioned medium (CM) from human HCC cells on the activation of human HSC line, LX-2 by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and reverse transcriptase-polymerase chain reaction (RT-PCR). The replication of NDV was evaluated in LX-2 cells and primary-cultured mouse HSCs by flow cytometry or by a fluorescence microscope. Indices for hepatic fibrosis were determined in HSCs and a hepatic fibrosis mouse model by gelatin zymography, RT-PCR, Western blot and Sirius red staining after NDV infection. Colocalization of NDV virions and alpha-smooth muscle actin (alpha-SMA) were detected by double immunofluorescence staining. Detection of apoptosis was carried out in liver tissues of NDV-treated mice by the TdT-mediated dUTP nick-end labelling assay. RESULTS: Tumour-CM and transforming growth factor-beta1 (TGF-beta1) could promote the proliferation and activation of LX-2 cells, indicated by the enhanced expression of alpha-SMA, collagen I, tissue inhibitor of metalloproteinase (TIMP)-1 and TGF-beta1. Activated HSCs facilitated the replication of NDV, thereby repressing the secretion of MMP, the expression of these indices for hepatic fibrosis and the expression of alpha-SMA and collagen fibrils in hepatic fibrosis of the mouse induced by carbon tetrachloride. CONCLUSIONS: HCC cells promote the activation of HSCs and NDV attenuates the activation and represses the hepatic fibrosis by selective replication in activated HSCs.

A role for tumor necrosis factor-alpha in the increased mortality associated with Vibrio vulnificus infection in the presence of hepatic dysfunction.

OBJECTIVE: The present study was designed to evaluate whether pre-existing hepatic dysfunction (cirrhosis) leads to increased morbidity and mortality, in part through an inappropriate in vivo tumor necrosis factor-alpha response. SUMMARY BACKGROUND DATA: Vibrio vulnificus is the most commonly isolated member of the noncholera Vibrio sp., responsible for fulminant and frequently fatal septicemia. A strong clinical association exists between hepatic dysfunction and increased morbidity and mortality from Vibrio sp. infection. However, the underlying mechanism behind this association has not been fully delineated. METHODS: Cirrhosis was induced in C57BL/6 (15 to 20 g) mice using thrice-weekly injections of carbon tetrachloride (CCl4) for 7 weeks. Either a 7.0 to 9.5 X 10(7) (low dose) or a 0.8 to 1.2 X 10(9) colony-forming unit (high dose) of V. vulnificus was administered through a mini-laparotomy incision via transgastric puncture into both cirrhotic and control animals. RESULTS: Mortality in cirrhotic mice to low- and high-dose Vibrio infection was 88% (7/8) and 100% (8/8), respectively, whereas mortality in control animals was 0% (0/8) and 12% (1/8), respectively (p<0.01). Tumor necrosis factor-alpha mRNA could be detected by reverse transcriptase polymerase chain reaction in livers and lungs from infected animals 2 and 4 hours after Vibrio administration in both control and cirrhotic animals. Lung and liver tumor necrosis factor-alpha bioactivity, however, was significantly lower in cirrhotic animals infected with Vibrio when compared with controls. Serum tumor necrosis factor-alpha was only sporadically detected in both groups of Vibrio-infected animals. When cirrhotic mice challenged with a low dose of Vibrio sp. were pretreated with 1.0 mg/kg body weight of a novel tumor necrosis factor-alpha receptor immunoadhesin, the increased mortality was completely prevented. CONCLUSIONS: Cirrhotic mice show increased mortality to Vibrio infection, and this increased mortality is dependent on an in vivo tumor necrosis factor-alpha response.