Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0239946 (liver fibrosis)
 8,268 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Activation of mesenchymal cells is a central event in the wound healing response of most tissues. In liver, the mesenchymal element responsible for organ fibrosis is the hepatic stellate cell (HSC) (formerly known as lipocyte or Ito cell). The phenotypic cascade of stellate cell activation in liver fibrosis has been well documented and involves both marked morphologic changes and upregulation of several functional components including extracellular matrix, cytokine receptors, contractile filaments and metalloproteinases. However, the genetic regulation of stellate cell activation is poorly understood. In an attempt to clone genes that are involved in the regulation of HSC activation we have combined cDNA library amplification by PCR with subtraction hybridization/differential screening, and have successfully identified genes induced in vivo during early stellate cell activation in a rat model of liver fibrosis. The subtracted cDNA library comprised less than 100 unique sequences. Of these, 13 clones with sizes ranging from 322 to 745 were sequenced and characterized. Gene induction in HSCs was monitored by RNAse protection assay during early liver injury induced by the hepatotoxin CCl4. The sequenced cDNAs corresponding to the known genes included type II transforming growth factor beta receptor, glutathione peroxidase I, transferrin and several clones encoding cellular retrotransposons, whose expression was not previously identified in non-parenchymal liver cells. In addition, one partial cDNA predicted a zinc-finger motif, suggesting a possible role of a novel transcriptional regulator. Our approach represents a valuable strategy for clarifying in vivo regulatory mechanisms of mesenchymal cell activation in wound healing.
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PMID:Early genes induced in hepatic stellate cells during wound healing. 930 69

This experiment was carried out to investigate the role of antioxidants such as vitamin C and E, selenium and Nigella sativa (NS) on the prevention of carbon tetrachloride (CCl4)-induced liver fibrosis in rabbits. It was found that superoxide dismutase (SOD) values in all of the treated groups were significantly lower than those of the control at 12th week of experiment (p < 0.05), while at 6th week and 12th week of experiment glutathione peroxidase (GSH-Px) values in the vitamin C treated group were significantly different from the control (p < 0.05). Histopathologically, hepatocellular necrosis, degeneration and advanced fibrosis were found in the control group. Lesions were minor and only confined to midzonal regions without centrilobular necrosis and fibrosis in the NS treated animals (group B). The lesions observed in the vitamin C treated animals (group C) were similar to that of the control group. Parenchymal changes with fibrosis were less in selenium and vitamin E treated animals (group D) than in those of the control group, but more obvious than in NS group. Histopathological findings demonstrate that NS might, at least partly, be successful in the prevention of liver fibrosis in rabbits. Vitamin E plus selenium had little therapeutic effect and vitamin C seemed to be ineffective, as far as the results of this study are concerned.
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PMID:The role of antioxidant vitamins (C and E), selenium and Nigella sativa in the prevention of liver fibrosis and cirrhosis in rabbits: new hopes. 1136 85

In liver cirrhosis, liver tissue becomes progressively substituted by fibrosis, ultimately leading to architectural distortion, liver circulatory changes, and liver failure. Some data support the hypothesis that protein undernutrition may play a role in the development and progression of nonalcoholic liver cirrhosis and that this progression is at least partially mediated by changes in glutathione peroxidase (GPX), superoxide dismutase (SOD), and other antioxidative systems, leading to an increase in lipid peroxidation. We analyzed the effects of protein deficiency on liver Cu, Fe, Zn, Mn, and Se in carbon tetrachloride (CCl4)-induced liver cirrhosis, the relation of protein undernutrition and these trace elements with the activity of some hepatic antioxidative enzymatic mechanisms, and the relation of all of them with morphological and biochemical changes in 40 male adult Sprague-Dawley rats divided in four groups. Liver cirrhosis was induced by intraperitoneal injection of CCl4 to 10 rats fed a 2% protein diet and another 10 fed a 18% protein control diet; two further groups included rats without cirrhosis fed the 2% protein and the 18% protein diets. The study period lasted 6 wk. GPX, SOD, and lipid peroxidation products as well as Zn, Cu, Mn, Se, and Fe were determined in liver samples. We found that liver GPX and Se were reduced in the cirrhotic animals, especially in the low-protein-fed ones, protein deficiency, but not cirrhosis, exerting the main effects. A close correlation was found between liver GPX and serum albumin and weight loss and an inverse one among GPX and hepatocyte ballooning, liver fibrosis, and fat, histomorphometrically determined. These results suggest a pathogenetic role of decreased GPX in the progression of liver disease, which may become enhanced by concomitant protein undernutrition. In addition to iron, the levels of which were increased in the malnourished rats, no differences were found regarding the other trace elements, SOD activity, and lipid peroxidation products.
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PMID:Effects of protein deficiency on liver trace elements and antioxidant activity in carbon tetrachloride-induced liver cirrhosis. 1283 97

Protein undernutrition, alterations of hormones such as IGF-1, testosterone and cortisol, and increased lipid peroxidation-which may be related with deranged metabolism of some elements such as iron (Fe), zinc (Zn), manganese (Mn), selenium (Se) or copper (Cu)-may contribute to muscle damage in non alcoholic cirrhosis. Here, we analyse the effect of protein deficiency on muscle Cu, Fe, Zn, Mn and Se in carbon-tetrachloride (CCl(4)) induced liver cirrhosis. We also study the association between protein undernutrition and these trace elements with the activity of glutathione peroxidase (GPX), superoxide dismutase (SOD) and lipid peroxidation products, and how all these are related with muscle morphological changes in 40 male adult Sprague-Dawley rats. Liver cirrhosis was induced by intraperitoneal injection of CCl(4) to 10 rats fed a 2% protein diet, and to another 10 fed a 18% protein control diet. Two further groups included rats without cirrhosis fed the 2% protein and the 18% protein diets. After sacrifice (6 weeks later), we found type IIa fibre atrophy in the cirrhotic animals, especially in the low-protein fed ones and this was due to protein deficiency. Muscle Fe increased in low protein fed cirrhotic rats. No relationship was found between muscle changes and any of the hormones, enzymes and trace elements analysed, or with liver fibrosis. These results suggest that muscle atrophy observed in CCl(4)-induced cirrhosis is related with protein deficiency, but not with cirrhosis itself.
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PMID:Protein deficiency and muscle damage in carbon tetrachloride induced liver cirrhosis. 1456 4

In this study, we developed a double-transgenic mouse model allowing hepatocyte-specific and regulated expression of the redox-modifying enzymes copper/zinc superoxide dismutase (SOD) and glutathione peroxidase (GPX) by using a tetracycline-regulatable gene expression system. Within this system, the SOD and GPX level can be regulated deliberately by addition or removal of doxycycline hydrochloride to the drinking water. As reactive oxygen species (ROS) have been implicated in a number of pathological conditions, such as atherosclerosis, thrombosis, or liver fibrosis, processes that are also frequently associated with enhanced levels of plasminogen activator inhibitor-1 (PAI-1), it was the aim of the present study to investigate the influence of SOD and GPX overexpression on the regulation of PAI-1. PAI-1 mRNA and protein levels in tetracycline transactivator-dependent SOD-overexpressing double-transgenic mice reached values 2.5- to threefold above the normal mRNA level. By applying doxycycline, a deinduction of the PAI-1 levels was observed. By using the same protocol, PAI-1 mRNA and protein levels were enhanced in GPX double-transgenic mice, and again this response was blunted by the addition of doxycycline. These studies provide some new information regarding the role of ROS within the proteolytic processes in hepatocytes that require PAI-1.
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PMID:Enhanced plasminogen activator inhibitor-1 expression in transgenic mice with hepatocyte-specific overexpression of superoxide dismutase or glutathione peroxidase. 1524 48

Hepatic fibrosis involves the interplay of many factors including reactive oxygen species. Recent reports described antioxidant properties of glycosaminoglycans (GAGs). Since several findings have shown that hyaluronic acid (HYA) and chondroitin-4-sulphate (C4S) may act as antioxidant molecules, the aim of this research was to evaluate the antioxidant effects of HYA and C4S treatment in a rat model of liver fibrosis. The effect on tissue inhibitors of metalloproteinases (TIMPs) was also studied. Liver fibrosis was induced in rats by eight intraperitoneal injections of CCl4, twice a week for 6 weeks. HYA or C4S alone (25 mg/kg) or HYA and C4S in combination (12.5 + 12.5 mg/kg) were administered daily by the same route during the 6 weeks. At the end of the 6-week treatment period (24 h after the last dose of GAGs), the following parameters were evaluated: (1) serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, as index of hepatic cell disruption; (2) hepatic conjugated dienes (CD), as index of lipid peroxidation; (3) hepatic TIMPs activity and expression; (4) hepatic superoxide dismutase (SOD) and glutathione peroxidase (GPx) activity, as index of endogenous defences; (5) hepatic hydroxyproline, as index of collagen deposition. CCl4-induced liver fibrosis enhanced lipid peroxidation and TIMPs activation, increased ALT and AST, depleted antioxidants SOD and GPx, and caused collagen deposition in liver tissue. Treatment with GAGs, especially when in combination, successfully reduced ALT and AST rise, lipid peroxidation by evaluating conjugated dienes, TIMPs activation and mRNA expression, partially restored SOD and GPx activities, and limited collagen deposition in the hepatic tissue. The data obtained showed that these molecules were able to limit hepatic injury induced by chronic CCl4 intoxication and especially limited liver fibrosis. They also confirm that HYA and C4S may exert antioxidant mechanism, while reduction of TIMPs expression suggests that GAGs may influence MMPs and TIMPs imbalance in liver fibrosis.
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PMID:The antioxidant and antifibrogenic effects of the glycosaminoglycans hyaluronic acid and chondroitin-4-sulphate in a subchronic rat model of carbon tetrachloride-induced liver fibrogenesis. 1527 69

Astragalosides is the major active constituent of Radix Astragali. The present study was carried out to investigate the effect of crude astragalosides fraction (CAF) on rats liver fibrosis and its possible mechanisms. Hepatic fibrosis was induced by subcutaneous injection with 50% CCl(4) in Sprague-Dawley rats. The amount of CCl(4) administered was 1 mg kg(-1). The alanine aminotransferase (ALT), aspartate aminotransferase (AST) levels in plasma and hydroxyproline (Hyp), malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH-px) contents in liver tissue were assayed by spectrophotometry. The hyaluronic acid (HA) and procollagen III (PC III) were assessed by radioimmunoassay. Tumor necrosis factor-alpha (TNF-alpha) and transforming growth factor-beta1 (TGF-beta1) levels in culture supernatants of Kupffer cells (KCs) were determined with ELISA. Liver samples collected after 8 weeks of CCl(4) treatment were stained with hematoxylin-eosin (HE) and massion, and scored. Intragastric administration of CAF (10, 20 and 40 mg kg(-1)) significantly decreased indices of liver and spleen, the serum transaminase activities, HA and PC III levels, and Hyp and MDA contents in liver tissue in rats of hepatic fibrosis. Decreased SOD and GSH-px levels were reversed after administration of CAF. Histopathological scores showed CAF had inhibitory effect on the progression of hepatic fibrosis. In the in vitro experiments, CAF significantly reduced TNF-alpha and TGF-beta1 levels in culture supernatants of KCs. The results showed CAF significantly inhibited the progression of hepatic fibrosis induced by CCl(4), and the inhibitory effect of CAF on hepatic fibrosis might be associated with its ability to scavenge free radical and inhibit the production of TNF-alpha and TGF-beta1 from activated KCs.
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PMID:Effects and mechanisms of crude astragalosides fraction on liver fibrosis in rats. 1619 23

Oxidative stress can be implicated as a cause of liver fibrosis. In this sense, Ginkgo Biloba Extract (EGB), an antioxidant, may be beneficial in restraining liver fibrosis. The aim of this study was to evaluate the effects of EGB on experimental liver fibrosis. Rat liver fibrosis was induced by intraperitoneal injection of carbon tetrachloride (CCl4) twice a week for 8 weeks. Three groups of rats received EGB (0.25, 0.5 and 1.0 g/kg, respectively) by stomach everyday. CCl4 administration induced liver fibrosis, which was inhibited by EGB in a dose-dependent manner. The histopathologic score of fibrosis, liver function and the levels of plasma hyaluronic acid (HA) and laminin (LN) were significantly improved in rats treated with CCl4 + EGB, compared with those treated with CCl4 only (p < 0.01 or p < 0.05). The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were notably elevated, while malondialdehyde (MDA) content was significantly decreased in the rats treated with CCl4 + EGB (p < 0.01 or p < 0.05). Inhibition of hepatic stellate cell (HSC) activation and nuclear factor kappaBP65 (NF-kappaBP65) expression was demonstrated in the livers of EGB-treated rats. The activation of NF-kappaB was significantly suppressed in EGB-treated rats determined by electrophoretic mobility shift assay (EMSA). Furthermore, EGB reduced expressions of transforming growth factor-beta1 (TGF-beta1) and collagen I mRNA. In conclusion, EGB is able to ameliorate liver injury and prevent rats from CCl4-induced liver fibrosis by suppressing oxidative stress. This process may be related to inhibiting the induction of NF-kappaB on HSC activation and the expression of TGF-beta1.
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PMID:Therapeutic effects and molecular mechanisms of Ginkgo biloba extract on liver fibrosis in rats. 1643 43

Our aim was to study the protective effect of quercitin on liver cirrhosis induced by carbon tetrachloride (CCl(4)) in rats and its relationship with liver morphology. Thirty male Wistar rats weighing 200-250 g were randomly divided into three groups: control, CCl(4), and CCl(4)+ quercetin. Rats in the experimental groups were given CCl(4) (0.5 ml/kg i.p.), diluted 1:6 in vegetable oil (5 mmol/kg body wt), at 10:00 p.m. every 4 days for 17 weeks. Quercetin (500 microl/kg i.p.; 150 micromol/kg body wt) or vehicle was administered at 6:00 p.m. for the last 3 weeks of the study. Control group rats were given only olive oil for the same period. At the end of the 17 weeks, all rats were sacrificed. Blood samples were taken for determination of serum indicators (ALT, AST, total bilirubin, conjugated bilirubin, factor V) and the livers were dissected out and divided into two parts: one was homogenized and the supernatant was used for measurement of superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPx) activities, as well as lipid peroxidation. The other part was used for the histopathological study. CCl(4) caused a marked rise in serum levels of ALT, AST, total bilirubin, and conjugated bilirubin, as well as a decrease in factor V (P<0.05). Lipid peroxidation levels were significantly increased, whereas GSH, SOD, catalase, GPx, and GST levels were decreased in the liver of CCl(4)-treated rats. Quercetin (50 mg/kg/day) successfully attenuated these effects of CCl(4). We conclude that quercetin has beneficial effects on liver fibrosis in rats by enhancing antioxidant enzyme activity and decreasing the pro-oxidant effect.
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PMID:Quercetin prevents oxidative stress in cirrhotic rats. 1743 69

The aim of this study was to investigate the protective effect of breviscapine extracted from the Chinese herb Erigeron breviscapus on liver injury in diabetic rats induced by streptozotocin. Treatment with breviscapine significantly reduced liver weight, liver lipid level, fatty liver and liver fibrosis score in diabetic rats. Treatment with breviscapine also significantly decreased lipid peroxidation malondiadehyde levels and increased the activities of antioxidative enzymes such as superoxide dismutase, catalase and glutathione peroxidase in diabetic liver. Immunohistochemical observations revealed that macrophage (ED-1-positive cells) infiltration in diabetic liver was inhibited by treatment with breviscapine. Western blot analysis showed that the expression of transforming growth factor-beta1 in diabetic liver was lowered by breviscapine treatment. In conclusion, our results indicate that breviscapine has potential as a treatment for diabetic liver injury through attenuating liver lipid accumulation and oxidative stress.
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PMID:Prevention of early liver injury by breviscapine in streptozotocin-induced diabetic rats. 1756 45


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