Co-administration of cyclosporine A alleviates thioacetamide-induced liver injury

AIM: To investigate the effects of cyclosporine A (CsA) on thioacetamide (TAA)-induced liver injury. METHODS: CsA was co-administrated (7.5 μg/kg body weight per day, i.p.) into rat to investigate the role of CsA on TAA-(200 mg/kg body weight per 3 d for 30 d, i.p.) induced liver injury. RESULTS: The data show that TAA caused liver fibrosis in rat after 30 d of treatment. CsA alleviates the morphological changes of TAA-induced fibrosis in rat liver. The blood glutamyl oxaloacetic transaminase (GOT)/glutamyl pyruvic transaminase (GPT) in the TAA-injury group is elevated compared to that of the normal rat. Compared with the TAA-injury group, the blood GOT/GPT and TGFβ1(by RT-PCR analysis) are reduced in the CsA plus TAA-treated rat. The level of the transforming growth factor receptor I (TGFβ-R1) in the CsA plus TAA-treated group shows higher than that in the TAA only group, but shows a lower level of the fibroblast growth factor receptor 4 (FGFR4) in the CsA plus TAA-treated group, when using the Western blot analysis. After immunostaining of the frozen section, TGFβ-R1 and FGFR4 are more concentrated in rat liver after CsA plus TAA injury. CONCLUSION: This result suggests that CsA has an alleviated effect on TAA-induced liver injury by increasing the multidrug resistance P-glycoprotein and could be through the regulation of TGFβ-R1 and FGFR4.     

Melatonin inhibits nuclear factor kappa B activation and oxidative stress and protects against thioacetamide induced liver damage in rats

BACKGROUND/AIMS: Free radical-mediated oxidative stress has been implicated in the pathogenesis of acute liver injury. The aim of our study was to investigate whether melatonin, a potent free radical scavenger could prevent fulminant hepatic failure in rats. METHODS: Liver damage was induced by two consecutive injections of thioacetamide (TAA, 300 mg/kg/i.p.) at 24 h intervals. Treatment with melatonin (3 mg/kg/daily, i.p) was initiated 24 h prior to TAA. RESULTS: Twenty-four h after the second TAA injection, serum liver enzymes and blood ammonia were lower in rats treated with TAA+melatonin compared to TAA (P<0.001). Liver histology was significantly improved and the mortality in the melatonin-treated rats was decreased (P<0.001). The increased nuclear binding of nuclear factor kappa B in the livers of the TAA-treated rats, was inhibited by melatonin. The hepatic levels of thiobarbituric acid reactive substances, protein carbonyls and inducible nitric oxide synthase were lower in the TAA+melatonin-treated group (P<0.01), indicating decreased oxidative stress and inflammation. CONCLUSIONS: In a rat model of TAA-induced fulminant hepatic failure, melatonin improves survival and reduces liver damage and oxidative stress. The results suggest a causative role of oxidative stress in TAA-induced hepatic damage and suggest that melatonin may be utilized to reduce liver injury associated with oxidative stress.     

Down-regulation of TGFbeta1 and leptin ameliorates thioacetamide-induced liver injury in lipopolysaccharide-primed rats

Pretreatment with a low dose of bacterial endotoxin (lipopolysaccharide, LPS) caused the reduction of cytochrome P450 (CYP) enzymes and inflammatory factors which are capable of protecting the liver from a lethal LPS challenge. However, the effects of LPS pretreatment on the expression of transforming growth factor beta1 (TGFbeta1) and leptin in thioacetamide (TAA)-induced liver fibrosis remain unknown. In this study, Sprague-Dawley rats were pretreated intraperitoneally with LPS (5 mg/kg body weight) for 24 h, and subsequently treated with TAA (200 mg/kg body weight/ 3 days) for 1 month to examine the effects of LPS on TAA-injured rats. LPS pretreatment was associated with lower granulation and lower (P < 0.05) GOT/GPT than in TAA-injured rats. The LPS-pretreated group had less collagen (Sirius red histochemical staining). Semiquantitative RT-PCR showed that the levels of collagen 3 and TGFbeta1 mRNAs were lower (P < 0.05) in the liver of LPS-pretreated rats than in TAA-injured rats. TGFbetaRI mRNA in the liver of LPS-pretreated rats exceeded (P < 0.05) that in TAA-injured rats. LPS pretreatment reduced the leptin content (Western blot) below that of TAA-injured rats. These results imply that LPS pretreatment (endotoxin tolerance) alleviates the TAA-induced liver fibrosis of rats by reducing TGFbeta1 and leptin content.     

Antifibrotic effect of N-acetyl-seryl-aspartyl-lysyl-proline on bile duct ligation induced liver fibrosis in rats

AIM:To investigate the preventive effect of N-acetyl-seryl-aspartyl-lysyl-proline (AcSDKP) on bile duct ligation (BDL)induced liver fibrosis in rats. METHODS:Liver fibrosis in rats was induced by BDL and AcSDKP was infused subcutaneously for 2 wkvia a osmotic minipump (Alzet 2ML4) immediately after BDL operation. After scarifying, serum and liver specimens were collected. Hematoxylin and eosin staining, Sirius red staining, enzyme linked immunosorbent assay, Western blot or real-time polymerase chain reaction were used to determinate liver functions, histological alterations, collagen deposition, mRNA expression of markers for fibroblasts, transforming growth factor-β1 (TGF-β1) and bone morphogenetic protein-7 (BMP-7). RESULTS:When compared to model rats, chronic exogenous AcSDKP infusion suppressed profibrogenicTGF-β1 signaling, α-smooth muscle actin positivity (α-SMA), fibroblast specific protein-1 (FSP-1) staining and collagen gene expression. Col Ⅰ, Col Ⅲ, matrix metalloproteinase-2, tissue inhibitors of metallopro-teinase-1 and tissue inhibitors of metalloproteinase-2 mRNA expressions were all significantly downregulated by AcSDKP infusion (2.02 ± 1.10vs 14.16 ± 6.50, 2.02 ± 0.45vs 10.00 ± 3.35, 2.91 ± 0.30vs 7.83 ± 1.10, 4.64 ± 1.25 vs 18.52 ± 7.61, 0.46 ± 0.16 vs 0.34 ± 0.12, respectively, P 0.05). Chronic exogenous AcSDKP infusion attenuated BDL-induced liver injury, inflammation and fibrosis. BDL caused a remarkable increase in alanine transaminase, aspartate transaminase, total bilirubin, and prothrombin time, all of which were reduced by AcSDKP infusion. Mast cells, collagen accumulation, α-SMA, TGF-β1, FSP-1 and BMP-7 increased. The histological appearance of liver specimens was also improved. CONCLUSION:Infusion of exogenous AcSDKP attenu-ated BDL-induced fibrosis in the rat liver. Preservation of AcSDKP may be a useful therapeutic approach in the management of liver fibrosis.     

Murine model to study brain,behavior and immunity during hepatic encephalopathy

AIM:To propose an alternative model of hepatic encephalopathy(HE) in mice,resembling the human features of the disease.METHODS:Mice received two consecutive intraperitoneal injections of thioacetamide(TAA) at low dosage(300 mg/kg).Liver injury was assessed by serum transaminase levels(ALT) and liver histology(hematoxylin and eosin).Neutrophil infiltration was estimated by confocal liver intravital microscopy.Coagulopathy was evaluated using prolonged prothrombin and partial thromboplastin time.Hemodynamic parameters were measured through tail cuff.Ammonia levels were quantified in serum and brain samples.Electroencephalography(EEG) and psychomotor activity score were performed to show brain function.Brain edema was evaluated using magnetic resonance imaging.RESULTS:Mice submitted to the TAA regime developed massive liver injury,as shown by elevation of serum ALT levels and a high degree of liver necrosis.An intense hepatic neutrophil accumulation occurred in response to TAA-induced liver injury.This led to mice mortality and weight loss,which was associated with severe coagulopathy.Furthermore,TAA-treated mice presented with increased serum and cerebral levels of ammonia,in parallel with alterations in EEG spectrum and discrete brain edema,as shown by magnetic resonance imaging.In agreement with this,neuropsychomotor abnormalities ensued 36 h after TAA,fulfilling several HE features observed in humans.In this context of liver injury and neurological dysfunction,we observed lung inflammation and alterations in blood pressure and heart rate that were indicative of multiple organ dysfunction syndrome.CONCLUSION:In summary,we describe a new murine model of hepatic encephalopathy comprising multiple features of the disease in humans,which may provide new insights for treatment.     

Effects of aspirin and enoxaparin in a rat model of liver fibrosis

AIM To examine the effects of aspirin and enoxaparin on liver function, coagulation index and histopathology in a rat model of liver fibrosis.METHODS Forty-five male Sprague-Dawley rats were randomly divided into the control group(n = 5) and model group(n = 40). Thioacetamide(TAA) was used to induce liver fibrosis in the model group. TAA-induced fibrotic rats received TAA continuously(n = 9), TAA + low-dose aspirin(n = 9), TAA + high-dose aspirin(n = 9) or TAA + enoxaparin(n = 9) for 4 wk. All rats were euthanized after 4 wk, and both hematoxylin-eosin and Masson staining were performed to observe pathological changes in liver tissue. RESULTS Liver fibrosis was assessed according to the METAVIR score. Compared with untreated cirrhotic controls, a significant improvement in fibrosis grade was observed in the low-dose aspirin, high-dose aspirin and enoxaparin treated groups, especially in the high-dose aspirin treated group. Alanine aminotransferase and total bilirubin were higher, albumin was lower and both prothrombin time and international normalized ratio were prolonged in the four treatment groups compared to controls. No significant differences among the four groups were observed.CONCLUSION Aspirin and enoxaparin can alleviate liver fibrosis in this rat model.     

Leptin administration exacerbates thioacetamide-induced liver fibrosis in mice

AIM: To investigate the effects of leptin administration on liver fibrosis induced by thioacetamide (TAA). METHODS: Twenty-four male C57Bl/6 mice were randomly allocated into four groups, which were intra-peritoneally given saline (2 mL/kg), leptin (1 mg/kg), TAA (200 mg/kg), TAA (200 mg/kg) plus leptin (1 mg/kg) respectively, thrice a week. All mice were killed after 4 wk. The changes in biochemical markers, such as the levels of alanine aminot-ransferase (ALT) and aspartate aminotransferase (AST) in serum and superoxide dismutase (SOD), malondialdehyde (MDA) in liver were determined. For histological analysis, liver tissues were fixed with 10% buffered formalin, embedded with paraffin. Hematoxylin-eosin (HE) staining and picric acid-Sirius red dyeing were performed. The level of α1(I) procollagen mRNA in liver tissues was analyzed by RT-PCR. RESULTS: Apparent liver fibrosis was found in TAA group and TAA plus leptin group. Compared to saline group, the levels of ALT and AST in serum and MDA in liver increased in TAA group (205.67±27.69 U/L vs50.67±10.46 U/L, 177.50±23.65 U/L vs 76.33±12.27 U/L, 2.60±0.18 nmol/mg pro vs 1.91±0.14 nmol/mg pro, P<0.01) and in TAA plus leptin group (256.17±22.50 U/L vs 50.67±10.46 U/L, 234.17±27.37 U/L vs 76.33±12.27 U/L, 2.97±0.19 nmol/mg pro vs 1.91±0.14 nmol/mg pro,P<0.01). The level of SOD in livers decreased (51.80±8.36 U/mg pro vs 81.52±11.40 U/mg pro, 35.78±6.11 U/mg pro vs 81.52± 11.40 U/mg pro, P<0.01) and the level of α1(I) procollagen mRNA in liver tissues also increased (0.28±0.04 vs 0.11± 0.02, 0.54±0.07 vs 0.11±0.02, P<0.01). But no significant changes were found in leptin group and saline group. Compared to TAA group, ALT, AST, MDA, and α1(I) procollagen mRNA and grade of liver fibrosis in TAA plus leptin group increased (256.17±22.50 U/L vs 205.67± 27.69 U/L, P<0.05; 234.17±27.37 U/L vs 177.50±23.65 U/L, P<0.05; 2.97±0.19 nmol/mg pro vs 2.60±0.18 nmol/mg pro,P<0.05; 0.54±0.07 vs 0.28±0.04, P<0.01; 3.17 vs 2.00, P<0.05), and the level of SOD in liver decreased (35.78±6.11 U/mg pro vs 51.80±8.36 U/mg pro, P<0.05). There were similar changes in the degree of type I collagen deposition confirmed by picric acid-Sirius red dyeing. CONCLUSION: Leptin can exacerbate the degree of TAA-induced liver fibrosis in mice. Leptin may be an important factor in the development of liver fibrosis.     

Atorvastatin and rosuvastatin do not prevent thioacetamide induced liver cirrhosis in rats

AIM:To examine whether the administration of atorvastatin and rosuvastatin would prevent experimentallyinduced hepatic cirrhosis in rats.METHODS:Liver cirrhosis was induced by injections of thioacetamide(TAA).Rats were treated concurrently with TAA alone or TAA and either atorvastatin(1,10 and 20 mg/kg) or rosuvastatin(1,2.5,5,10 and 20 mg/kg) given daily by nasogastric gavage.RESULTS:Liver fibrosis and hepatic hydroxyproline content,in the TAA-treated group was significantly higher than those of the controls [11.5 ± 3.2 vs 2.6 ± 0.6 mg/g protein(P = 0.02)].There were no differences in serum aminotransferase levels in the TAA controls compared to all the groups treated concomitantly by statins.Both statins used in our study did not prevent liver fibrosis or reduce portal hypertension,and had no effect on hepatic oxidative stress.Accordingly,the hepatic level of malondialdehyde was not lower in those groups treated by TAA + statins compared to TAA only.In vitro studies,using the BrdU method have shown that atorvastatin had no effect of hepatic stellate cells proliferation.Nevertheless,statin treatment was not associated with worsening of liver damage,portal hypertension or survival rate.CONCLUSION:Atorvastatin or rosuvastatin did not inhibit TAA-induced liver cirrhosis or oxidative stress in rats.Whether statins may have therapeutic applications in hepatic fibrosis due to other etiologies deserve further investigation.     

Expression patterns of cell cycle-related proteins in a rat cirrhotic model induced by CCl4 or thioacetamide

To analyze the aberrant expression of cell cycle-related proteins and their biological significance in relation to cirrhosis, we compared the cirrhotic patterns induced by two different types of cirrhotic agents, CCl₄ and thioacetamide (TAA) in rats. CCl₄ or TAA treatment was given to rats for 8 or 30 weeks, respectively, and the livers were removed at 9, 20, and 30 weeks after the experiment began. The TAA-induced fibrotic pattern was different from the CCl₄-induced one, in terms of the formation of fibrous connective tissue and the proliferation of bile ductule cells. Cholangiofibrosis and clear cell foci were also observed in TAA-treated rats at 30 weeks. Histological examination revealed severe cirrhotic changes at 9 weeks in CCl₄-treated rats and at 30 weeks in TAA-treated rats. Immunoblotting for cyclin D1, E, A, B, and proliferating cell nuclear antigen (PCNA) and their counterpart protein kinases (CDK2, 4, and CDC2) showed significant overexpression in rats with severely cirrhotic livers. The p53 tumor suppressor protein increased dramatically in the CCl₄-treated group, while it was not detected in the livers of TAA-treated rats. Upregulation of p21^WAF1, a CDK inhibitory protein, was detected in TAA-treated rats, but not in CCl₄-treated rats. Immunohistochemical data for cyclin D1, E, and PCNA were well correlated with immunoblotting data; these proteins were increased in hepatocytes surrounding the cirrhotic lesions, suggesting that hepatocyte regeneration is correlated with cell cycle-related protein expression in cirrhotic liver. In the TAA-treated rats, the expression of these proteins was increased both in hepatocytes and in ductule cells. Our data suggest that liver cirrhosis induced by CCl₄ or TAA is associated with alterations in cell cycle-related proteins, and that the expression of these proteins is responsible for hepatocyte regeneration in the damaged liver and may be involved in liver carcinogenesis. Received: May 1, 2000 / Accepted: August 25, 2000     

Effects of interferon-alpha on expression of hepatic stellate cell and transforming growth factor-β1 and α-smooth muscle actin in rats with hepatic fibrosis

AIM: To investigate the effect of interferon-α(IFN-α) on preventing or reversing hepatic fibrosis in rat experimental model induced by CCl4.METHODS: One hundred and ten Sprague-Dawley rats were divided into five groups: group A (normal controls,n=18), group B (fibrotic model controls, n=22), group C (IFN-α prevention, n=22) initially treated with intra-muscular injection of IFN-α in saline daily at the doses of 1&#215;105U for 6wk, group D (IFN-α treatment, n=24) treated with intra-muscular injection of IFN-α in saline daily at the doses of 1&#215;105U for 6wk after the first 6wk, group E (0.9% sodium chloride treatment control, n=24) treated with intra-muscular injection of 0.01mL/kg daily for 6wk after the first 6wk. At the end of the experiment, all rats of each group were killed. Samples of the liver obtained by biopsy were subjected to histological, immunohistochemical and electron microscopic studies for the expressions of transforming growth factor-β1(TGF-β1) and α-smooth muscle actin (α-SMA).RESULTS: The expressions of TGF-β1, the number of activated hepatic stellate cells and α-SMA in hepatic tissue of group C were significantly less than those of group B(P&lt;0.01). The degree of fibrosis score in group B was also significantly less than that of group C under light microscope (P&lt;0.01).CONCLUSION: IFN-α can inhibit the production of TGF-β1, decrease HSC activation and stimulate its apoptosis.     

Involvement of P53 and Bax/Bad triggering apoptosis in thioacetamide-induced hepatic epithelial cells

AIM: Thioacetamide (TAA) has been used in studying liver fibrosis and cirrhosis, however, the mechanisms of TAA-induced apoptosis in liver are still unclear. The hepatic epithelial cell line clone 9 was cultured and treated with TAA to investigate the causes of cell death. METHODS: The cell viability of TAA-induced clone 9 cells was determined using MTT assay. Total cellular GSH in TAA-induced clone 9 cells was measured using a slight modification of the Tietze assay. The activity of caspase 3 in TAA-induced clone 9 cells was monitored by the cleavage of DEVD-p-nitroanaline. TUNEL assay and flow cytometry were applied for the determination of DNA fragmentation and the proportion of apoptosis in TAA-induced clone 9 cells, respectively. The alterations of caspase 3, Bad, Bax and Phospho-P53 contents in TAA-induced clone 9 cells were measured by Western blot. RESULTS: The experimental data indicated that TAA caused rat hepatic epithelial cell line clone 9 cell death in a dose-and time-dependent manner; 60% of the cells died (MTT assay) within 24 h after 100 mg/L TAA was applied. Apoptotic cell percentage (TUNEL assay) and caspase 3 activities were highest after 100 mg/L TAA was added for 8 h. The release of GSH and the elevation in caspase content after TAA treatment resulted in clone 9 cell apoptosis via oxidative stress and a caspase-dependent mechanism. The phospho-p53, Bax and Bad protein expressions in clone 9 cells were increased after TAA treatment. CONCLUSION: These results reveal that TAA activates p53, increases caspase 3, Bax and Bad protein contents, perhaps causing the release of cytochrome c from mitochondria and the disintegration of membranes, leading to apoptosis of cells.     

Protective effects of 5,4′-dihydroxy-3.5′- dimethoxy-7-O-β-D-glucopyranosyloxy-flavone on experimental hepatic injury

AIM: To investigate the pharmacological effects of rice flavone (5,4‘-dihydroxy-3‘,5‘-dimethoxy-7-O-β-D-glucopyranosyloxy-flavone, RF) separated from panicle-differentiating to flowing rice on rat experimental hepatic injury. METHODS: Models of rat acute hepatic injury induced by carbon tetrachloride (CCI4) administration, rat hepatic fibrosis induced by thioacetamide, injury of primary cultured rat hepatocytes induced by CCI4, respectively, were established. After treated with RF, content of serum alanine transaminase (ALT), aspartate aminotransferase (AST) and albumin (AIb), hyaluronic acid (HA), the activity of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and hydroxyproline (Hyp) were measured and liver tissue was observed pathologically by hematoxylin-eosin (HE) staining. Effects of RF on pathological changes, function index, enzyme of scavenging free radicals and blood rheology were evaluated. RESULTS: In model of rat acute hepatic injury inducedby CCI4, RF can significantly decrease the contents of serum ALT, AST, increase the content of AIb, improve the dropsy and fat denaturalization of hepatocytes. In model of rat hepatic fibrosis induced by thioacetamide, RF can inhibit the increase of HA, Hyp and whole blood viscosity, and improve the activities of GSH-Px and SOD, and inauricular microcirculation. CONCLUSION: RF has apparent protective effects onhepatic injury by increasing activity of GSH-Px and SOD, scavenging free radicals produced by CCI4, reducing blood viscosity, and improving microcirculation and blood supply.     

A protective effect of pyrrolidine dithiocarbamate in a rat model of liver cirrhosis.

BACKGROUND: Nuclear factor kappa B (NF-kappaB) activation, proinflammatory cytokines, and reactive oxygen species have been implicated as mediators of liver injury and fibrogenesis. We have shown recently that pyrrolidine dithiocarbamate (PDTC), an antioxidant and inhibitor of NF-kappaB activation, was protective in a rat model of acute liver failure. The aim of the present study was to examine the efficacy of PDTC in a chronic rat model of thioacetamide (TAA)-induced hepatic fibrosis. METHODS: Liver cirrhosis was induced by intraperitoneal injections of TAA (200 mg/kg) twice weekly for 12 weeks. Two groups of rats also received PDTC (either 20 or 60 mg/kg, i.p. for 12 weeks). RESULTS: TAA administration induced liver cirrhosis, which was inhibited by PDTC in a dose-dependent manner. The histopathologic score of fibrosis, the spleen weight, and hepatic hydroxyproline were significantly lower in the rats treated with TAA+PDTC compared with TAA only (P<0.001). The hepatic levels of thiobarbituric acid reactive substances and protein carbonyls after 12 weeks of treatment were also lower in the rats treated with TAA+PDTC (P=0.02 and 0.01, respectively), indicating reduced oxidative stress. Immunohistochemical studies and in situ hybridization demonstrated inhibition of stellate cell (alpha smooth muscle actin positive) activation, tissue inhibitor of metalloproteinase-2, and collagen alpha1(I) gene expression in the livers of the PDTC-treated rats. As determined by Northern blot analysis, PDTC had no inhibitory effect on collagen alpha1(I) gene expression in the rat hepatic stellate cells-T6 cells in vitro. CONCLUSIONS: PDTC inhibits the development of liver cirrhosis in TAA-treated rats. The mechanism of action is associated with decreased oxidative stress and hepatic necroinflammation.     

Chronic permanent hypoxemia predisposes to mild elevation of liver stiffness

AIM:To evaluate the impact of long term permanent hypoxemia noticed in patients with non operated congenital cyanogenic cyanotic cardiopathy on liver stiffness.METHODS:We included ten adult patients with non operated inoperate cyanotic cardiopathy and ten matched patients for age and gender admitted to the gastroenterology department for proctologic diseases;Clinical and laboratory data were collected[age,gender,body mass index,oxygen saturation,glutamate oxaloacetate transaminase(GOT),glutamate pyruvate transaminase(GPT),glycemia and cholesterol].Measurement of hepatic stiffness by transient elastography was carried out in all patients using the Fibroscan device.All patients underwent an echocardiography to eliminate congestive heart failure.RESULTS:Among the patients with cyanotic cardiopathy,median liver stiffness 5.9±1.3 kPa was greater than control group(4.7±0.4 kPa)(P=0.008).Median levels of GOT,GPT,gamma-glutamyltransferase,glycemia and cholesterol were comparable in cardiopathy and control group.In regression analysis including age,gender,body mass index,oxygen saturation,GOT,GPT,glycemia,cholesterol showed that only oxygen saturation was related to liver stiffness(r=-0.63 P=0.002).CONCLUSION:Chronic permanent hypoxemia can induce mild increase of liver stiffness,but further studies are needed to explore the histological aspects of liver injury induced by chronic permanent hypoxemia.     

Specific type IV phosphodiesterase inhibitor ameliorates thioacetamide-induced liver injury in rats

BACKGROUND AND AIMS: Rolipram is a specific type IV phosphodiesterase inhibitor that suppresses the activity of immune cells and the production of pro-inflammatory cytokines. In this study, we assessed the effect of rolipram on acute liver injury using thioacetamide (TAA)-induced liver injury in rats as a model. METHODS: Rats were treated with rolipram (0.5-5 mg/kg, intraperitoneally) or vehicle and injected 30 min later with TAA (100 mg/kg, subcutaneously). Serum transaminase concentrations and tumor necrosis factor-alpha (TNF-alpha), interleukin 1beta (IL-1beta) and growth related oncogene/cytokine-induced neutrophil chemoattractant-1 (GRO/CINC-1) levels were measured and livers were examined for microscopic changes. Dose-dependent protection against TAA liver injury was based on transaminase levels and inflammatory cytokine production, and was measured 9 h after TAA when the peak release of cytokines occurred. RESULT: Rolipram suppressed liver injury based on serum aspartate transaminase (AST), alanine transaminase (ALT) and histology and reduced TNF-alpha, IL-1beta and GRO/CINC-1 levels. Rolipram, at doses of 0.5-5 mg/kg, suppressed serum transaminase and TNF-alpha production in a dose-dependent manner, and these effects were significant at doses of 2.5 and 5 mg/kg. CONCLUSION: In our rodent model of acute liver injury, rolipram clearly reduced liver damage and inhibited pro-inflammatory cytokine production. These results suggest that specific type IV phosphodiesterase inhibitors, such as rolipram, have potent hepatoprotective effects that are associated with suppressing inflammatory cytokine production.     

Combination of systemic thioacetamide (TAA) injections and ethanol feeding accelerates hepatic fibrosis in C3H/He mice and is associated with intrahepatic up regulation of MMP-2, VEGF and ICAM-1

BACKGROUND/AIMS: The induction of liver fibrosis is difficult in mice. Here, we intended to improve fibrosis induction by combination of thioacetamide (TAA) injections and ethanol (EtOH) feeding and to characterize features of liver damage in this model. Most experimental therapeutic studies are performed in mice without pre-damaged livers. METHODS: C3H mice were injected three times/week (0.15 mg/g body weight) and fed with EtOH. Tissue and serum samples were collected and analysed. RESULTS: Portal fibrosis was verified by van Gieson staining showing a mild fibrosis (score F2) in TAA-treated mice and liver fibrosis (score F4) in the combination group using TAA/EtOH. Consonant with the histological results, the fibrosis marker MMP-2 and alpha 1 procollagen (I) were elevated at week 10 and 15 after treatment initiation in the combination group, whereas tissue protective proteinase, TIMP-1, was 18.5-fold increased only at week 10 but normalized until week 15. Fibrosis development was associated with elevated ICAM-1 expression. CONCLUSIONS: Taken together, TAA/EtOH application was suitable to induce liver fibrosis characterized by typical bio-markers in C3H/He.     

Simvastatin for rats with thioacetamide-induced liver failure and encephalopathy

Background and Aim:  Nitric oxide (NO) inhibition aggravates hepatic damage and encephalopathy and increases mortality in rats with thioacetamide (TAA)-induced acute liver failure. Statins enhance NO synthase expression beyond their lipid-lowering capability, but the impact on encephalopathy remains unexplored. The aim of this study was to assess the effects of simvastatin on rats with TAA-induced acute liver damage and hepatic encephalopathy.
Methods:  Sprague–Dawley rats received TAA (350 mg/kg/day) or normal saline (NS) by intraperitoneal injection for 3 consecutive days. Two days before injections, each group was divided into three subgroups, taking (i) distilled water; (ii) simvastatin (20 mg/kg/day); or (iii) simvastatin plus N ^G-nitro- l -arginine methyl ester (L-NAME, 25 mg/kg/day) by oral gavage for 5 days. On the fifth day, severity of encephalopathy was assessed and plasma levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin and ammonia were measured.
Results:  The TAA subgroups showed higher ALT, AST, bilirubin and ammonia levels and lower motor activity counts as compared with the NS subgroups. Among the TAA-treated subgroups, rats with simvastatin treatment exerted higher motor activity counts and survival rate ( P  = 0.043), and a trend of lower ALT, AST, bilirubin and ammonia levels than those receiving saline. All rats that underwent simvastatin plus L-NAME treatment died during or after TAA injections.
Conclusions:  Simvastatin improved encephalopathy and survival in TAA-administered rats. The beneficial effect was offset by L-NAME, suggesting the role of NO in liver damage and encephalopathy.