[BIOCHEMICAL STUDIES ON CONNECTIVE TISSUE FORMATION IN EXPERIMENTAL THIOACETAMIDE LIVER CIRRHOSIS IN RATS].
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The chronic course of viral and toxic hepatitis is associated with the involvement into the pathogenesis of the disease of the immune processes whose mechanisms remain obscure. An attempt was made to elucidate the localization of immune complexes in the liver of rats with CCl4-induced cirrhosis of the liver according to the method by Yu. F. Kubitsa. Immune complexes were found in macrophages and lymphocytes infiltrating perivascular spaces and walls of veins undergoing degeneration. This indicates a possible role of cell-mediated reactions in the damage of blood vessels and hepatic parenchyma in cirrhosis. Immune complexes wee also found in the hepatocyte nuclei which suggests a damaging effect of antibody on the hepatic tissue in cases of complement activation.
RATIONALE AND OBJECTIVES: The authors investigated the usefulness of dynamic phosphorus-31 magnetic resonance (MR) spectroscopy in the assessment of hepatic function by studying the effect of a fructose load on a rat model of liver cirrhosis. METHODS: In vivo P-31 MR liver spectra of eight rats with bile duct ligature and 10 control rats were obtained every 4.6 minutes before and after intraperitoneal fructose load (10 mmol per kilogram of body weight). RESULTS: In the basal spectra of the experimental group, the phosphomonoester peak was higher than in the control group (P = .026). After the fructose load, the phosphomonoester peak increase and the inorganic phosphate peak decrease were significantly less marked in the experimental group (P = .003). There was a linear correlation between the serum level of bilirubin and the phosphomonoester increase (r = .61, P < .001). CONCLUSION: Dynamic P-31 MR spectroscopy may be useful in the assessment of hepatic function in chronic liver disease.
AIMS/METHODS: In the present study, we examined whether a nonpeptidic mimetic of Arg-Gly-Asp (RGD), which specifically inhibits RGD-dependent adhesion of CD4+ T lymphocytes or fibroblasts to fibronectin, can prevent thioacetamide-induced liver cirrhosis in rats. The nonpeptidic RGD mimetic, rather than the RGD peptide was utilized, since the peptide is rapidly degraded, and therefore, relatively ineffective for in vivo use. RESULTS: We now report that rats treated with thioacetamide and the RGD analogue SF-6,5 for 12 weeks had lower histopathologic scores than those treated with thioacetamide alone. Further improvement in liver histology was observed after another 8 weeks of treatment with the analogue SF-6,5. Quantitative microscopic analysis by computerized imaging morphometry of liver biopsies from the three groups and controls confirmed the semi-quantitative histopathologic scores (p < 0.001). After 3 months of treatment, the spleen weights in the SF-6,5-treated rats were 30% less than those of rats that received only thioacetamide, which indicated that the analogue-treated rats were less portal hypertensive. CONCLUSIONS: The observed inhibition of the progression of cirrhosis in rats by the nonpeptidic RGD analogue suggests that RGD mimetics may be useful therapeutically in inhibiting pathological processes that involve RGD recognition.
BACKGROUND & AIMS: An extrahepatic human neutrophil collagenase complementary DNA (matrix metalloprotease-8) cloned in an adenovirus vector was used as a therapeutic agent in cirrhosis. METHODS: A high titer of clinical-grade AdMMP8 was obtained. RESULTS: HeLa cells transduced with AdMMP8 expressed recombinant matrix metalloprotease-8 messenger RNA and matrix metalloprotease-8 protein. Matrix metalloprotease-8 in culture sups showed enzymatic activity against native collagen type I, which was inhibited by ethylenediaminetetraacetic acid, 1,10-phenanthroline, and tissue inhibitor of metalloprotease-1. In vivo transduction showed matrix metalloprotease-8 activity, and studies to establish the efficacy of this characterized vector were performed in CCl(4) and bile duct-ligated cirrhotic rats. Transduction with 3 x 10(11) viral particles per kilogram resulted in hepatic detection of both messenger RNA and protein matrix metalloprotease-8. A consistent response in fibrosis reversal was observed in CCl(4) rats. Liver fibrosis in bile duct-ligated cirrhotic animals was decreased in 45%, along with diminished hydroxyproline content, after AdMMP8 treatment. The expression of matrix metalloprotease-2 and matrix metalloprotease-3 was up-regulated in AdMMP8 rats. Free tissue inhibitor of metalloprotease-1, as an indirect measurement of active uncomplexed matrix metalloproteases, was also increased in the AdMMP8 groups. Transforming growth factor-beta messenger RNA was diminished, and matrix metalloprotease-9 and hepatocyte growth factor increased. Treatment in both models correlated with improvements in ascites, functional hepatic tests, and gastric varices, indicating diminished intrahepatic blood pressure in animals injected with AdMMP8. CONCLUSIONS: Therefore, therapy with the matrix metalloprotease-8 gene is promising for use in a clinical setting.
OBJECTIVE: To study whether retinolpalmitate, beta-carotene or lycopene could prevent liver cirrhosis induced by thioacetamide in rats. METHODS: In the control group liver cirrhosis was induced in male Wistar rats by intraperitoneal injections of TAA 200 mg/kg for 12 weeks. The three study groups received in addition to TAA either beta-carotene, lycopene or retinopalmitate by gavage through an orogastric tube. Histopathological analysis and determination of the hydroxyproline contents of the livers were performed at the end of the protocol. RESULTS: Rats treated with beta-carotene and TAA had lower histopathologic scores and reduced levels of hepatic hydroxyproline (P = 0.02) than those treated by TAA alone. A trend of decreased fibrosis was observed in the rats treated with lycopene and TAA although this lacked statistical significance. CONCLUSIONS: Beta-carotene attenuated liver cirrhosis induced by TAA in rats. The mechanism may be related to effects on hepatic stellate cells or to scavenging of free radicals by beta-carotene. Retinolpalmitate and lycopen had no significant beneficial effect.
OBJECTIVE: To evaluate the effects of portaazygous disconnection (PAD), portacaval shunt (PCS) and distal splenocaval shunt (DSCS) on the portosytemic shunting (PSS), hepatic function (HF), hepatic mitochondrial respiratory function (HMRF), oral glucose tolerance test (OGTT) and arterial ketone body ratio (KBR) in order to provide a sound basis for selecting suitable operations for patients. METHODS: Using a cirrhotic portal hypertensive model induced by CCl4/ethanol in Wistar rats, the PSS, HF, HMRF, OGTT and KBR were determined three weeks after PCS, DSCS and PAD. RESULTS: It was revealed that: (1) In the cirrhotic portal hypertension rats, the PSS increased significantly, HMRF and hepatic reserve function (HRF) decreased significantly when compared with the control rats. (2) At the time of first postoperative week, the mean blood glucose value in the 120-minute OGTT in each PAD, PCS and DSCS groups had significant differences compared with the cirrhotic control group. But during the second and third postoperative weeks, the mean blood glucose values in the 120-minute OGTT in both PAD and DSCS groups had no significant differences compared with the cirrhotic control group except for the PCS group. The values of KBR in the three operative groups decreased significantly compared with the cirrhotic control group during the two postoperative weeks. In the third postoperative week, only the values of KBR in the PCS group had a significant difference compared with the cirrhotic control group. (3) After PCS, the PSS was further increased; HF and HMRF were significantly decreased. Little improvement was found in the third postoperative week. (4) After DSCS and PAD, the above mentioned indices were less influenced, and they were restored more quickly than those in the PCS group. CONCLUSION: We found that PAD and DSCS are more desirable than PCS.
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Experimental liver cirrhosis was produced by administration of thioacetamide. Cirrhotic animals were divided into two groups: one group was given zinc sulphate and the second kept as cirrhotic control. Zinc-treated animals showed a restoration of normal hepatic and plasma zinc and copper levels. Similarly, plasma levels of aspartate aminotransferase, alanine aminotransferase, gamma-glutamyl aminotransferase, and total bilirubin decreased significantly. Light microscopic studies showed that most of the hepatocytes appeared normal in zinc-treated as compared with untreated cirrhotic animals. The amount of fibrin, reticulin, and collagen, which was high in the cirrhotic livers, decreased following zinc treatment. Staining with periodic acid Schiff's reagent showed the ability of hepatocytes to store glycogen after zinc treatment. These results revealed that zinc may have some beneficial effect in the treatment of liver cirrhosis.
The influence of cholestyramine and chenodeoxycholic acid on the induction of cirrhosis of the liver of the male Wistar strain rats was studied. The simultaneous dietary exposure of 1 g cholestyramine in 100 g diet prevented the development of cirrhosis induced by carbon tetrachloride. Whereas all the animals in the control group (CCl4-Exposure plus normal diet) developed cirrhosis, histologic examination showed cirrhosis in only 2 of 9 rats fed with diet containing cholestyramine. On the contrary, the exposure to chenodeoxycholic acid at a concentration of 1 g in 300 g diet potentiated the induction of cirrhosis. The experimental results support the clinical findings in which the administration of cholestyramine caused an improvement of liver function tests by cirrhosis.
RATIONALE AND OBJECTIVES: Three models of experimentally induced liver cirrhosis were evaluated for MRI research on chronic liver disease. The influence of different histopathologic changes in liver fibrosis and cirrhosis on relaxation times and signal intensities was studied in vitro and in vivo. METHODS: Liver fibrosis and cirrhosis in rats was induced by oral or subcutaneous administration of carbon tetrachloride (CCl4) or by thioacetamide (TAA) in drinking water. On histology, the degree of liver fibrosis and cirrhosis, fatty infiltration, iron accumulation, and inflammatory changes were measured semiquantitatively. The amount of connective tissue was quantitatively determined by morphometry. The results were correlated with T1 and T2 relaxation times and signal intensities of the liver studied in vitro by relaxometry and in vivo by MRI. RESULTS: In both groups with CCl4 administration, histology revealed different degrees of liver fibrosis and cirrhosis. Subcutaneous injection of CCl4 also resulted in increased fatty infiltration. On the contrary, TAA produced complete liver cirrhosis in all animals. Overall, there was a good correlation between the liver T2 relaxation time and the amount of connective tissue in liver fibrosis and cirrhosis. However, the degree of liver fibrosis and cirrhosis was also strongly correlated with the degree of inflammatory changes. In the group with CCl4 administration, there was a good correlation between the fatty infiltration and the T1 relaxation time, as well as with the liver signal intensity on the T1-weighted gradient echo sequence. An increased iron accumulation was also correlated with the degree of liver fibrosis/cirrhosis; however, there was no significant influence of the iron on relaxation times or signal intensities. CONCLUSIONS: The TAA model is easier to perform and more reliable in liver cirrhosis induction than the CCl4 models. Although there is a positive correlation between the T2 relaxation times and the degree of liver fibrosis/cirrhosis, this probably results from the associated inflammatory changes and is not caused by the increased amount of connective tissue.