Thioacetamide-induced Cirrhosis Research Articles

Hepatoprotective effects of Gynura procumbens against thioacetamide-induced cirrhosis in rats: Targeting inflammatory and oxidative stress signalling pathways

Gynura procumbens is an edible flowering plant that has been utilized as traditional therapy for numerous diseases. The current experiment investigates the hepatoprotective potentials of the ethanol extract of Gynura procumbens leaf (EEGPL) against thioacetamide (TAA)-induced liver cirrhosis in rats. Thirty Sprague Dawley rats were randomly divided into 5 clusters: A, rats received orally 10% Tween 80 and intraperitoneal (i.p) inoculation of sterile distal water; B, rats received orally10% Tween 80; C, rats received orally daily 50 mg/kg of silymarin, while groups; D and E, rats received orally daily doses of 200 and 400 mg/kg of EEGPL, respectively. Furthermore, B-E clusters received 200 mg/kg thioacetamide (i.p) three times a week for 60 days.The liver gross morphology of rats that received only TAA (B) revealed irregular rough surface layers compared to smoother livers of rats that received EEGPL. Histopathology of group B revealed clear hepatic necrosis and fibrous connective tissue, which were significantly reduced in C-E groups. EEGPL treatment caused a significant down-regulation of PCNA and α-SMA protein expressions. Antioxidant (SOD and CAT) enzymes in hepatic homogeneity were meaningfully lower, and MDA levels were significantly higher in TAA controls compared to those of C-E groups. Moreover, EEGPL treatment caused a reduction of TNF-α and IL-6 and increased expression of IL-10 cytokines. Therefore, the hepatoprotective potentials of EEGPL might be contributed to its modulation of detoxification enzymes, anti-inflammatory, and antioxidant activities.

Soluble Guanylyl Cyclase Activator BI 685509 Reduces Portal Hypertension and Portosystemic Shunting in a Rat Thioacetamide-Induced Cirrhosis Model.

Portal hypertension (PT) commonly occurs in cirrhosis. Nitric oxide (NO) imbalance contributes to PT via reduced soluble guanylyl cyclase (sGC) activation and cGMP production, resulting in vasoconstriction, endothelial cell dysfunction, and fibrosis. We assessed the effects of BI 685509, an NO-independent sGC activator, on fibrosis and extrahepatic complications in a thioacetamide (TAA)-induced cirrhosis and PT model. Male Sprague-Dawley rats received TAA twice-weekly for 15 weeks (300-150 mg/kg i.p.). BI 685509 was administered daily for the last 12 weeks (0.3, 1, and 3 mg/kg p.o.; n = 8-11 per group) or the final week only (Acute, 3 mg/kg p.o.; n = 6). Rats were anesthetized to measure portal venous pressure. Pharmacokinetics and hepatic cGMP (target engagement) were measured by mass spectrometry. Hepatic Sirius Red morphometry (SRM) and alpha-smooth muscle actin (αSMA) were measured by immunohistochemistry; portosystemic shunting was measured using colored microspheres. BI 685509 dose-dependently increased hepatic cGMP at 1 and 3 mg/kg (3.92 ± 0.34 and 5.14 ± 0.44 versus 2.50 ± 0.19 nM in TAA alone; P < 0.05). TAA increased hepatic SRM, αSMA, PT, and portosystemic shunting. Compared with TAA, 3 mg/kg BI 685509 reduced SRM by 38%, αSMA area by 55%, portal venous pressure by 26%, and portosystemic shunting by 10% (P < 0.05). Acute BI 685509 reduced SRM and PT by 45% and 21%, respectively (P < 0.05). BI 685509 improved hepatic and extrahepatic cirrhosis pathophysiology in TAA-induced cirrhosis. These data support the clinical investigation of BI 685509 for PT in patients with cirrhosis. SIGNIFICANCE STATEMENT: BI 685509 is an NO-independent sGC activator that was tested in a preclinical rat model of TAA-induced nodular, liver fibrosis, portal hypertension, and portal systemic shunting. BI 685509 reduced liver fibrosis, portal hypertension, and portal-systemic shunting in a dose-dependent manner, supporting its clinical assessment to treat portal hypertension in patients with cirrhosis.

Hepatoprotective effect of Baicalin against thioacetamide-induced cirrhosis in rats: Targeting NOX4/NF-κB/NLRP3 inflammasome signaling pathways

AimLiver cirrhosis is the result of a vicious cycle of both chronic oxidative stress and inflammation. NADPH oxidase-4 (NOX4) and its companion, NOD-like receptor protein 3 (NLRP3) inflammasome, are emerging as therapeutic targets of liver fibrosis. Main methodsBaicalin (BA), a natural flavone, has been investigated for its therapeutic potential against cirrhosis induced by thioacetamide (TAA) (200 mg/kg, twice/week) for 12 weeks in Sprague-Dawley rats. Two doses of BA were administered (25 and 75 mg/kg/day, orally, a week after TAA was stopped and continued for 4 weeks). Key findingsBA was able to reduce fibrosis visualized by Masson trichrome and immunohistochemical staining of the hepatic α-smooth muscle actin (α-SMA) and transforming growth factor-β1. Moreover, BA was able to ameliorate inflammation by reducing hepatic NLRP3 inflammasome subunits, NLRP3 and caspase-1, both parts of the complex responsible for the activation of different interleukins (IL), measured as IL-1β. In addition, BA was able to reduce hepatic nuclear factor kappa B (NF-κB)-driven inflammation through IL-6. BA targeted inflammation through its anti-oxidant ability evidenced by the enhancement of the hepatic superoxide dismutase (SOD) and reduced glutathione (GSH) activity and level, respectively, and the reduction of both hepatic malondialdehyde (MDA) and nitric oxide (NOx) contents. Treatment with BA significantly decreased TAA-induced elevation in hepatic NOX4, a key enzyme for reactive oxygen species (ROS) generation, as well as, inducible nitric oxide synthase (iNOS). Significancetherefore, the study could conclude, the anti-fibrotic effect of BA through TGF- β1/NOX4/NF-κB/NLRP3 pathway, exerting both anti-inflammatory and anti-oxidant effects.

High sucrose diet attenuates oxidative stress, inflammation and liver injury in thioacetamide-induced liver cirrhosis

AimsLiver cirrhosis is the main chronic liver disease and is considered a catabolic disease. Cirrhotic patients have a low energy intake and high energy expenditure at rest, leading to metabolic disorders. Malnutrition is associated with complications of cirrhosis and has been shown that a nutritional intervention with increase of energy intake improves the survival of cirrhotic patients. Therefore, our aim was to evaluate the effect of a high sucrose diet in the liver of animals with cirrhosis induced by thioacetamide and investigate the mechanism involved. Main methodsMale Wistar rats were divided into three groups: Control; Thioacetamide; and Thioacetamide + high sucrose diet. The thioacetamide was administrated (100 mg kg−1) intraperitoneally and the sucrose was offered in drinking water (300 g L−1). Key findingsThe administration of thioacetamide was associated with fibrosis and inflammatory infiltrate in the liver and increased levels of transaminases enzymes. The high sucrose diet promoted a reduction of theses parameters in cirrhotic rats. The malnutrition observed in cirrhotic rats was attenuated by the high sucrose diet shown by the improvements in weight loss, subcutaneous fat, and caloric intake. The high sucrose diet also attenuated the oxidative stress present in the liver of animals with thioacetamide-induced cirrhosis. SignificanceThe high sucrose diet had anti-inflammatory and anti-oxidant effects in the liver of animals with thioacetamide-induced cirrhosis. In addition, the high sucrose diet also improved malnutrition and catabolism present in cirrhosis. Thus, a high sucrose diet may be a therapeutic option for cirrhotic patients in a catabolic state.

Hepatoprotective Effect of Pomegranate Peel (Punica granatum L.) against Thioacetamide-Induced Cirrhosis

Pomegranate peel is widely used in the Middle east as a herbal medicine. However, their action as hepatoprotcetional agents still remains to be clarified, To understand its influence on liver vital functions, Fifty-seven male rats aged 13–15 weeks were divided into 15 categories at random including 5 rats per category, and were injected with either TAA, or administered PP plus injected TAA or administered Selenium plus injected TAA or administered with 0.9 percent normal saline solution as a control. The hepatoprotective effect of herbs was evaluated by measuring levels of serum marker enzymes such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and measurement Hepatocyte growth factor(HGF). The histological studies were also carried out to support the above parameters by using special stain Masson tricome and using immunofluorescent staining to examination the distribution of agrin in liver. The study found that the supplementation of pomegranate peel significantly (p < 0.05) reduced the damaging effects on the liver by TAA. ALT, AST, and HGF levels declined in treatment group due to the hepatic injury induced. A comparative histopathological research of the liver show between different groups demonstrated that pomegranate peel drive to normal liver architecture suggesting they may use as hepatoprotective alternative medication.

Protective Role of Pomegranate Peel (Punica granatum L) against Thioacetamide-Induced cirrhosis in a Rat Model

This study was designed to determine the effects of pomegranate peel on various antioxidiants measurements in liver cirrhosis of rats induced by thioacetamide.Fifty-seven male rats aged 13–15 weeks were randomly divided into 15 categories containing 5 rats per category, and were treated with either TAA, PP, or PP plus TAA or Selenium plus TAA or administered with 0.9% physiological saline solution as a control. The hepatoprotective effect of herbs was evaluated by measuring levels of antioxidiant marker enzymes such as Glutathione Peroxidase (GSH-Px) and Superoxide Dismutase (SOD) and measurement Malondialdehyde (MDA). The histological studies were also carried out to support the above parameters by using special stain Haemotoxlin &amp; eosin and using immunofluorescent staining to examine the distribution of DDR2 in the liver. The study found that the supplementation of pomegranate peel significantly (p&lt; 0.05) reduced the damaging effects on the liver by TAA. GSH, SOD increased in the treatment group, but serum MDA level was declined due to the hepatic injury induced. A comparative histopathological research of the liver between different groups demonstrated that pomegranate peel, drive to normal liver architecture suggesting they may use as a hepatoprotective alternative medication

Modulatory effects of curcumin, silybin-phytosome and alpha-R-lipoic acid against thioacetamide-induced liver cirrhosis in rats

Liver cirrhosis is the final consequence of a progressive fibrotic process characterized by excessive collagen deposition and destruction of the normal liver architecture. This study aimed to investigate the protective effects of curcumin, silybin-phytosome and alpha-R-lipoic acid against thioacetamide-induced cirrhosis. Male rats were allocated into five groups of which one group received saline and served as normal control. Animals from groups 2–5 were treated with thioacetamide administered intraperitoneally at a dose of 200mg/kg 3 times per week for 7weeks. Group 2 was left untreated while groups from 3 to 5 were given a daily oral dose of curcumin, silybin-phytosome or alpha-R-lipoic acid simultaneously with thioacetamide. Increases in hepatic levels of malondialdehyde (MDA) and protein carbonyls (Pr Co) associated with thioacetamide administration were partially blocked in those groups receiving supplements. Glutathione (GSH) depletion, collagen deposition, matrix metalloproteinase-2 (MMP-2) activity, transforming growth factor-β1 (TGF-β1) level as well as α-smooth muscle actin (α-SMA) and heat shock protein-47 (HSP-47) gene expressions were also decreased in response to supplements administration. Serological analysis of liver function and histopathological examination reinforced the results. In conclusion, the present study highlights the antioxidant and the antifibrotic potentials of these supplements against chronic liver diseases caused by ongoing hepatic damage.

Parenteral Solution of Nutritional Hepatotrophic Factors Improves Regeneration in Thioacetamide-induced Cirrhotic Livers after Partial Hepatectomy

Liver resection is a suitable option for the treatment of certain hepatic conditions, particularly hepatocarcinomas, in patients with cirrhosis. However, this disease impairs liver regeneration, which increases the risk of liver failure and postoperative death. Supportive treatments for regeneration of the remaining liver may be useful for the recovery of these patients. We demonstrated that nutritional hepatotrophic factors (NHF) is an effective regenerative stimulus for cirrhotic livers in rats subjected to partial hepatectomy (PH). The rats with thioacetamide-induced cirrhosis were subjected to PH, and they were divided into 2 groups. One group received intraperitoneal administration of NHF, and the other group received saline solution. After 12 days, biometric data, collagen content, hepatocyte regeneration (proliferation cell nuclear antigen immunochemistry), and profibrotic gene expression (Collagen-α1, matrix metalloproteinase 2, tissue inhibitor of metalloproteinase 1, and transforming growth factor beta 1) were assessed. The results indicated that the rats treated with NHF after PH had an increased liver size, a reduced amount of collagen, and a higher hepatocyte proliferation index compared with the rats that underwent PH alone. In addition, collagen-α1 gene expression was decreased in the NHF-treated rats. Thus, postoperative improvement in the liver morphology following NHF treatment may cause a significant decrease in the risk of liver failure and mortality after hepatic resection.

Role of Differentiation of Liver Sinusoidal Endothelial Cells in Progression and Regression of Hepatic Fibrosis in Rats

Capillarization, characterized by loss of differentiation of liver sinusoidal endothelial cells (LSECs), precedes the onset of hepatic fibrosis. We investigated whether restoration of LSEC differentiation would normalize crosstalk with activated hepatic stellate cells (HSC) and thereby promote quiescence of HSC and regression of fibrosis. Rat LSECs were cultured with inhibitors and/or agonists and examined by scanning electron microscopy for fenestrae in sieve plates. Cirrhosis was induced in rats using thioacetamide, followed by administration of BAY 60-2770, an activator of soluble guanylate cyclase (sGC). Fibrosis was assessed by Sirius red staining; expression of α-smooth muscle actin was measured by immunoblot analysis. Maintenance of LSEC differentiation requires vascular endothelial growth factor-A stimulation of nitric oxide-dependent signaling (via sGC and cyclic guanosine monophosphate) and nitric oxide-independent signaling. In rats with thioacetamide-induced cirrhosis, BAY 60-2770 accelerated the complete reversal of capillarization (restored differentiation of LSECs) without directly affecting activation of HSCs or fibrosis. Restoration of differentiation to LSECs led to quiescence of HSCs and regression of fibrosis in the absence of further exposure to BAY 60-2770. Activation of sGC with BAY 60-2770 prevented progression of cirrhosis, despite continued administration of thioacetamide. The state of LSEC differentiation plays a pivotal role in HSC activation and the fibrotic process.

1 CGMP Signaling Regulates Liver Sinusoidal Endothelial Cell (SEC) Phenotype and Accelerates Reversal of Cirrhosis

Differentiated, but not capillarized, SEC promote reversion of stellate cells (HSC) to quiescence. Capillarization precedes fibrosis In Vivo. Thus restoring SEC differentiation may promote resolution of fibrosis. This study examines whether NO maintains SEC phenotype In Vitro through the soluble guanylate cyclase (sGC)/cGMP/protein kinase G (PKG) pathway and whether In Vivo activation of sGC accelerates reversal of capillarization and cirrhosis. Methods Rat SEC were cultured for 2 days with inhibitors or agonists and examined by scanning EM for fenestrae in sieve plates, defining features of SEC differentiation. Controls: SEC cultured alone (complete defenestration) or with 40 ng/ml VEGF (fully fenestrated). Thioacetamide-induced (200mg/kg i.p. biw for 3 weeks) cirrhosis was followed by 0.3 mg/ kg p.o. BAY 60-2770 (kind gift from Bayer Schering Pharma), an NO-independent activator of sGC. Sirius red staining for fibrosis was assessed blindly (semi-quantitative score 0-6). In Vitro studies 1.SEC cultured with VEGF plus L-NAME (nitric oxide synthase inhibitor), with VEGF/ODQ (sGC inhibitor) or with VEGF/Rp-8-pCPT-PET-cGMPS (PKG inhibitor) defenestrated completely. Thus the NO/cGMP pathway is necessary to maintain fenestrated SEC. 2.SEC grown with DETA-NONOate (6μM) produced similar levels of NO and cGMP to SEC cultured with VEGF, but SEC defenestrated. SEC grown with YC-1 (sGC activator) or 8-pCPT-cGMP (cGMP analog) defenestrated. Thus the NO/cGMP pathway alone is insufficient to maintain SEC phenotype. 3.SEC grown with VEGF, L-NAME and DETA-NONOate, with VEGF, L-NAME and YC-1, or with VEGF, ODQ and 8-pCPT-cGMP remained fully fenestrated. Thus maintenance of SEC phenotype requires both VEGF and the NO/cGMP pathway. 4.BAY60-2770 alone was not sufficient to reverse HSC activation, but reversal required co-cultured SEC and was NO-independent. In Vivo studies with BAY 60-2770 1-week treatment normalized cGMP level in SEC [0.82± 0.02 fmol/μg protein in normal vs 0.83± 0.05 fmol/μg protein in treated vs 0.47±0.06 fmol/μg protein in solvent controls (p= 0.011)] and completely reversed capillarization [normal porosity 6.80 ± 0.31%; 6.24±0.37% in treated vs 3.14 ± 0.22% in solvent controls (p<0.01)], but cirrhosis persisted. 2-week treatment caused reversal to bridging fibrosis vs persistent cirrhosis in solvent controls. Conclusions Both VEGF independent of NO plus VEGF-stimulated NO acting through the sGC/cGMP/PKG pathway are necessary and sufficient to maintain SEC differentiation. Reversal of HSC activation by sGC activation requires the presence of SEC. Stimulation of sGC reversed capillarization, which promoted reversal of cirrhosis.

2 IL-1β and Inflammasome Activation in Non-Alcoholic Steatohepatitis is MyD88-Dependent and Amplified by TLR9 Ligands in Mice

Differentiated, but not capillarized, SEC promote reversion of stellate cells (HSC) to quiescence. Capillarization precedes fibrosis In Vivo. Thus restoring SEC differentiation may promote resolution of fibrosis. This study examines whether NO maintains SEC phenotype In Vitro through the soluble guanylate cyclase (sGC)/cGMP/protein kinase G (PKG) pathway and whether In Vivo activation of sGC accelerates reversal of capillarization and cirrhosis. Methods Rat SEC were cultured for 2 days with inhibitors or agonists and examined by scanning EM for fenestrae in sieve plates, defining features of SEC differentiation. Controls: SEC cultured alone (complete defenestration) or with 40 ng/ml VEGF (fully fenestrated). Thioacetamide-induced (200mg/kg i.p. biw for 3 weeks) cirrhosis was followed by 0.3 mg/ kg p.o. BAY 60-2770 (kind gift from Bayer Schering Pharma), an NO-independent activator of sGC. Sirius red staining for fibrosis was assessed blindly (semi-quantitative score 0-6). In Vitro studies 1.SEC cultured with VEGF plus L-NAME (nitric oxide synthase inhibitor), with VEGF/ODQ (sGC inhibitor) or with VEGF/Rp-8-pCPT-PET-cGMPS (PKG inhibitor) defenestrated completely. Thus the NO/cGMP pathway is necessary to maintain fenestrated SEC. 2.SEC grown with DETA-NONOate (6μM) produced similar levels of NO and cGMP to SEC cultured with VEGF, but SEC defenestrated. SEC grown with YC-1 (sGC activator) or 8-pCPT-cGMP (cGMP analog) defenestrated. Thus the NO/cGMP pathway alone is insufficient to maintain SEC phenotype. 3.SEC grown with VEGF, L-NAME and DETA-NONOate, with VEGF, L-NAME and YC-1, or with VEGF, ODQ and 8-pCPT-cGMP remained fully fenestrated. Thus maintenance of SEC phenotype requires both VEGF and the NO/cGMP pathway. 4.BAY60-2770 alone was not sufficient to reverse HSC activation, but reversal required co-cultured SEC and was NO-independent. In Vivo studies with BAY 60-2770 1-week treatment normalized cGMP level in SEC [0.82± 0.02 fmol/μg protein in normal vs 0.83± 0.05 fmol/μg protein in treated vs 0.47±0.06 fmol/μg protein in solvent controls (p= 0.011)] and completely reversed capillarization [normal porosity 6.80 ± 0.31%; 6.24±0.37% in treated vs 3.14 ± 0.22% in solvent controls (p<0.01)], but cirrhosis persisted. 2-week treatment caused reversal to bridging fibrosis vs persistent cirrhosis in solvent controls. Conclusions Both VEGF independent of NO plus VEGF-stimulated NO acting through the sGC/cGMP/PKG pathway are necessary and sufficient to maintain SEC differentiation. Reversal of HSC activation by sGC activation requires the presence of SEC. Stimulation of sGC reversed capillarization, which promoted reversal of cirrhosis.

Acetylcholinesterase activity in an experimental rat model of Type C hepatic encephalopathy

Patients with liver malfunction often suffer from hepatic encephalopathy, a neurological complication which can affect attention and cognition. Diverse experimental models have been used to study brain alterations that may be responsible for hepatic encephalopathy symptoms. The aim of the study was to determine whether cognitive impairment found in cirrhosis could be due to disturbance of acetylcholinesterase activity. Acetylcholinesterase activity was assessed in the brains of Wistar rats with thioacetamide-induced cirrhosis. The cirrhotic group displayed up-regulation of acetylcholinesterase levels in the entorrhinal cortex, anterodorsal and anteroventral thalamus and accumbens, whereas down-regulation was found in the CA1, CA3 and dentate gyrus of the hippocampus. Our results indicate that the experimental model of hepatic encephalopathy by chronic administration of thioacetamide presents alterations of acetylcholinesterase activity in brain limbic system regions, which play a role in attention and memory.

Mammillary body alterations and spatial memory impairment in Wistar rats with thioacetamide-induced cirrhosis

Brain tissue of patients diagnosed with hepatic encephalopathy exhibits cellular morphological changes that could be associated with memory impairment. The mammillary nuclei, located in the posterior part of the hypothalamus, are important for spatial memory formation. This work aimed to assess spatial reference memory and cellular changes in the mammillary nuclei of cirrhotic rats. Spatial reference memory of Wistar rats with thioacetamide-induced cirrhosis was assessed in the Morris water maze. Total cell number of neurons and glial cells and volume of the mammillary nuclei were quantified by stereology. Neuronal and astrocytic nuclear volume in mammillary nuclei and CA1 dorsal hippocampal subfield were assessed by nucleator probe. Cirrhotic rats showed an impaired spatial reference memory in comparison with control animals. Total number of neurons and glial cells were unaltered. In the medial mammillary nucleus (MMn), glial fibrillary acidic protein-immunoreactive astrocytes decreased in the cirrhotic group while the lateral part was unaffected. The medial part of the MMn was larger in the cirrhotic group. The cirrhotic rats showed morphometric cellular changes characterised by an increased neuronal and astrocytic nuclear volume in all the mammillary nuclei and CA1 hippocampal region. These findings suggest that cirrhotic rats show spatial memory impairment that could be linked to astrocytes and neuronal impairment in mammillary nuclei and hippocampus.

Effect of cold ischemia–warm reperfusion on the cirrhotic rat liver

Cirrhosis is known to induce capillarization of the sinusoidal endothelial cells (SECs) and collagenization of the space of Disse, resulting in a reduced access of plasma and plasma-dissolved substances to hepatocytes due to their limited diffusion in the extravascular space. The aim of the present study was to use a well known effect of cold ischemia-warm reperfusion (CI-WR) on liver SECs, that is, their retraction and detachment, progressing to a denudation of the SEC lining. The disappearance of the capillarized SEC lining would improve the access of plasma and plasma-dissolved substances to the hepatocytes and consequently might improve the metabolic function of cirrhotic livers. This study was performed using the isolated perfused rat liver model subjected to 24-hour CI followed by a 60-minute WR in thioacetamide-induced cirrhosis. Liver microcirculation was evaluated using the multiple indicator dilution curve (MIDC) technique. Hepatocyte, SEC, and Kupffer cell functions were evaluated using specific elimination processes. As occurs in normal livers, CI-WR induced extensive SEC necrosis with a marked reduction of the hyaluronic acid elimination. By contrast, the hepatic microcirculation was not modified: vascular, extravascular, and the cellular spaces were similar before and following CI-WR. In addition, the hepatic metabolic functions, as evaluated by propranolol and taurocholate hepatic uptake, were neither improved nor decreased, as were Kupffer cell functions. The present data strongly suggest that capillarization of SECs plays a lesser role than collagenization of the space of Disse in the reduced exchange between sinusoids and hepatocytes in thioacetamide-induced cirrhotic rat livers, which appear to be quite resistant to CI-WR.

Thioacetamide-induced cirrhosis in selenium-adequate mice displays rapid and persistent abnormity of hepatic selenoenzymes which are mute to selenium supplementation

Selenium reduction in cirrhosis is frequently reported. The known beneficial effect of selenium supplementation on cirrhosis is probably obtained from nutritionally selenium-deficient subjects. Whether selenium supplementation truly improves cirrhosis in general needs additional experimental investigation. Thioacetamide was used to induce cirrhosis in selenium-adequate and -deficient mice. Selenoenzyme activity and selenium content were measured and the influence of selenium supplementation was evaluated. In Se-adequate mice, thioacetamide-mediated rapid onset of hepatic oxidative stress resulted in an increase in thioredoxin reductase activity and a decrease in both glutathione peroxidase activity and selenium content. The inverse activity of selenoenzymes (i.e. TrxR activity goes up and GPx activity goes down) was persistent and mute to selenium supplementation during the progress of cirrhosis; accordingly, cirrhosis was not improved by selenium supplementation in any period. On the other hand, selenium supplementation to selenium-deficient mice always more efficiently increased hepatic glutathione peroxidase activity and selenium content compared with those treated with thioacetamide, indicating that thioacetamide impairs the liver bioavailability of selenium. Although thioacetamide profoundly affects hepatic selenium status in selenium-adequate mice, selenium supplementation does not modify the changes. Selenium supplementation to cirrhotic subjects with a background of nutritional selenium deficiency can improve selenium status but cannot restore hepatic glutathione peroxidase and selenium to normal levels.

Prevention of liver cirrhosis in rats by curcumin

Curcumin, the major polyphenolic compound in turmeric, has been shown to attenuate hepatic damage in several animal models of liver injury. The aim of the present study was to examine the efficacy of curcumin in preventing thioacetamide-induced cirrhosis and to unravel the mechanism of curcumin's effect on hepatic fibrosis in rats. Liver cirrhosis was induced by thioacetamide (TAA; 200 mg/kg, i.p.) twice weekly for 12 weeks. One group of rats concomitantly received curcumin (300 mg/kg/day, by gavage for 12 weeks); the control group received the solvent at identical amounts and duration. TAA administration induced liver cirrhosis, which was inhibited by curcumin. Liver histopathology, hydroxyproline levels and spleen weights were significantly lower in the rats treated with TAA+curcumin compared with TAA only (P<0.001). Immunohistochemical studies and in situ hybridization demonstrated inhibition of hepatic stellate cell (alpha smooth muscle actin-positive) activation and collagen alpha1 (I) gene expression in the livers of the TAA+curcumin-treated rats. Curcumin reduced oxidative stress as shown by the decreased hepatic nitrotyrosine staining in the curcumin+TAA-treated rats. Curcumin treatment had no effect on pre existing liver cirrhosis. As determined by in vitro studies using the rat HSC-T6 cell line, curcumin had no direct inhibitory effect on collagen alpha1 (I) messenger RNA expression. Further studies in these cells using reverse transcriptase-polymerase chain reaction demonstrated that curcumin had no effect on the expression of PDGF-induced TIMP-1 and TIMP-2, TGFbeta1, TGFbeta2 and MCP-1 but significantly inhibited tumor necrosis factor alpha expression. Curcumin had no effect on hepatic stellate cells proliferation. Zymography showed that curcumin had no effect on matrix metalloproteinase-2 activity. Curcumin inhibited the development of TAA-induced liver cirrhosis mainly due to its anti-inflammatory activities and not by a direct anti-fibrotic effect. As curcumin ingestion is safe in humans, it may be reasonable to assess in clinical studies the beneficial effect of curcumin in slowing the development of liver cirrhosis.

Nitroflurbiprofen, a Nitric Oxide-Releasing Cyclooxygenase Inhibitor, Improves Cirrhotic Portal Hypertension in Rats

We studied whether administration of nitroflurbiprofen (HCT-1026), a cyclooxygenase inhibitor with nitric oxide (NO)-donating properties, modulates the increased intrahepatic vascular tone in portal hypertensive cirrhotic rats. In vivo hemodynamic measurements (n = 8/condition) and evaluation of the increased intrahepatic resistance by in situ perfusion (n = 5/condition) were performed in rats with thioacetamide-induced cirrhosis that received either nitroflurbiprofen (45 mg/kg), flurbiprofen (30 mg/kg, equimolar concentration to nitroflurbiprofen), or vehicle by intraperitoneal injection 24 hours and 1 hour prior to the measurements. Additionally, we evaluated the effect of acute administration of both drugs (250 micromol/L) on the intrahepatic vascular tone in the in situ perfused cirrhotic rat liver (endothelial dysfunction and hyperresponsiveness to methoxamine) and on hepatic stellate cell contraction in vitro. Typical systemic adverse effects of nonsteroidal anti-inflammatory drugs, such as gastrointestinal ulceration, renal insufficiency, and hepatotoxicity, were actively explored. In vivo, nitroflurbiprofen and flurbiprofen equally decreased portal pressure (8 +/- 0.8 and 8.4 +/- 0.1 mm Hg, respectively, vs 11.8 +/- 0.6 mm Hg) and reduced the total intrahepatic vascular resistance. Systemic hypotension was not aggravated in the different treatment groups (P = .291). In the perfused cirrhotic liver, both drugs improved endothelial dysfunction and hyperresponsiveness. This was associated with a decreased hepatic thromboxane A(2)-production and an increased intrahepatic nitrate/nitrite level. In vitro, nitroflurbiprofen, more than flurbiprofen, decreased hepatic stellate cells contraction. Flurbiprofen-treated rats showed severe gastrointestinal ulcerations (bleeding in 3/8 rats) and nefrotoxicity, which was not observed in nitroflurbiprofen-treated cirrhotic rats. Treatment with nitroflurbiprofen, an NO-releasing cyclooxygenase inhibitor, improves portal hypertension without major adverse effects in thioacetamide-induced cirrhotic rats by attenuating intrahepatic vascular resistance, endothelial dysfunction, and hepatic hyperreactivity to vasoconstrictors.

The Effects of Light and Moderate-Heavy Ethanol Exposure on the Development of Cirrhosis in Rats

Daily, light ethanol consumption has beneficial effects on liver recovery following partial hepatectomy and acute liver failure in rats. The aim of the present study was to determine whether such consumption has a beneficial, deleterious, or no effect on the progression of chronic hepatitis to cirrhosis in rats. Adult, male, Sprague-Dawley rats (n = 66) were gavaged with light (1.0 g/kg/day) or moderate-heavy (3.0 g/kg) ethanol in water daily for the final 8 weeks of a 10-week period of thioacetamide-induced cirrhosis. Control rats were gavaged with water alone. Compared to results in water-fed controls, light-ethanol exposure had beneficial or no effects, while moderate-heavy ethanol exposure had deleterious effects on hepatic inflammation, function, regenerative activity, and fibrosis. The results of this study indicate that daily, light ethanol exposure does not have a deleterious effect on the progression of chronic liver disease to cirrhosis in this animal model.

Expression patterns of cytokine, growth factor and cell cycle-related genes after partial hepatectomy in rats with thioacetamide-induced cirrhosis

To examine the differences in the responses of normal and cirrhotic livers to partial hepatectomy in relation to the factors influencing liver regeneration. Cirrhosis was induced in rats by administration of thioacetamide. Untreated rats were used as controls. The control rats as well as the cirrhotic rats were subjected to 70% partial hepatectomy. At different time points after hepatectomy, the livers were collected and the levels of cytokines, growth factors and cell cycle proteins were analyzed. After hepatectomy, the cirrhotic remnant expressed significantly lower levels of cyclin D1, its kinase partner, cdk4, and cyclin E as compared to the controls up to 72 h post hepatectomy. Significantly lower levels of cyclin A and cdk2 were also observed while the cdk inhibitor, p27 was significantly higher. In addition, the cirrhotic group had lower IL-6 levels than the control group at all time points up to 72 h following resection. The data from our study shows that impaired liver regeneration in cirrhotic remnants is associated with low expression of cyclins and cdks. This might be the consequence of the low IL-6 levels in cirrhotic liver remnant which would in turn influence the actions of transcription factors that regulate genes involved in cell proliferation and metabolic homeostasis during the regeneration process.

Expression patterns of cytokine, growth factor and cell cycle-related genes after partial hepatectomy in rats with thioacetamide-induced cirrhosis

Expression patterns of cytokine, growth factor and cell cycle-related genes after partial hepatectomy in rats with thioacetamide-induced cirrhosis