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.     

Treatment of pig serum-induced rat liver fibrosis with Boschniakia rossica, oxymatrine and interferon-α

AIM: To investigate the effect of Boschniakia rossica (BR), oxymatrine (OM) and interferon-alpha (IFN-α) lb on the therapy of rat liver fibrosis and its mechanism. METHODS: By establishing a rat model of pig serum-induced liver fibrosis, liver/weight index and serum alanine transaminase (ALT) were observed to investigate the therapeutic effect of BR, OM and IFN-α Radioimmunoassay was utilized to measure procollagen type Ⅲ (PCⅢ) and collagen type Ⅳ (CⅣ). RT-PCR was used to assay the expression of liver transforming growth factor- beta 1 (TGF-β1) mRNA. Immunohistochemistry of alpha-smooth muscle actin (α-SMA) and pathologic changes of liver tissues were also under investigation. RESULTS: Serum PCⅢ and CⅣ in BR, OM and IFN-α groups were significantly declined compared with those in model group, and their RT-PCR revealed that TGF-β1 mRNA expression was also reduced more than that in model group. Immunohistochemistry demonstrated that α-SMA also declined more than that in model group. Serum ALT in IFN-α, control and model groups was within normal level. Serum ALT in BR group had no significant difference from those of IFN-α, control and model groups. Serum ALT in ON group was significantly higher than those in BR, IFN-α,model, and control groups. CONCLUSION: BR, OM and IFN-α can prevent pig serum-induced liver rat fibrosis by inhibiting the activation of hepatic stellate cells and synthesizing collagen. OM has hepatotoxicity to rat liver fibrosis induced by pig serum.     

Treatment of pig serum-induced rat liver fibrosis with Boschniakia rossica, oxymatrine and interferon-α

AIM: To investigate the effect of Boschniakia rossica (BR), oxymatrine (OM) and interferon-alpha (IFN-α) 1b on the therapy of rat liver fibrosis and its mechanism. METHODS: By establishing a rat model of pig serum-induced liver fibrosis, liver/weight index and serum alanine transaminase (ALT) were observed to investigate the therapeutic effect of BR,OM and IFN-α. Radioimmunoassay was utilized to measure procollagen type Ⅲ (PCⅢ) and collagen type Ⅳ (CIV). RT-PCR was used to assay the expression of liver transforming growth factor- beta 1 (TGF-β1) mRNA. Immunohistochemistry of alpha-smooth muscle actin (α-SMA) and pathologic changes of liver tissues were also under investigation. RESULTS: Serum PCⅢ and CIV in BR, OM and IFN-α groups were significantly declined compared with those in model group, and their RT-PCR revealed that TGF-β1 mRNA expression was also reduced more than that in model group. Immunohistochemistry demonstrated that α-SMA also declined more than that in model group. Serum ALT in IFN-α, control and model groups was within normal level. Serum ALT in BR group had no significant difference from those of IFN-α, control and model groups. Serum ALT in OM group was significantly higher than those in BR, IFN-α, model, and control groups. CONCLUSION: BR, OM and IFN-α can prevent pig serum-induced liver rat fibrosis by inhibiting the activation of hepatic stellate cells and synthesizing collagen. OM has hepatotoxicity to rat liver fibrosis induced by pig serum.     

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.     

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.     

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.     

Hepatic content of collagens and laminin in rat model of experimental liverfibrosis

AIM The hepatic content of collagens (type I, Ⅲ and Ⅶ) and laminin (LN) in rat model of experimentalliver fibrosis was observed to find out their roles in the pathogenesis of liver fibrosis.METHODS The experimental rat model was established by immunological injury induced by injectinghuman albumin. Histopathological and immunohistochemical methods were used to measure the hepaticcontent of collagens and laminin in the fibrotic rat livers.RESULTS The hepatic contents of collagens (type I, Ⅲ, Ⅶ) and LN in the fibrotic rat livers weresignificantly increased as compared with those in the control group, and they were found to be mainlylocalized in the portal space, central veins and fibrous septa. Electron microscopic study showed that pro-collagens were present around the “activated” hepatic stellate cells (HSC) and the hepatocytes atrophied.CONCLUSION Pathological deposition of collagens (type Ⅰ, Ⅲ and Ⅶ ) and laminin was the fundamentallesion of liver fibrosis. HSC may be the major cellular source of collagens (type Ⅰ, Ⅲ and Ⅶ) and laminin inthe liver tissue.     

Protective effects of a polymethoxy flavonoids-rich Citrus aurantium peel extract on liver fibrosis induced by bile duct ligation in mice

Objective: To evaluate the possible protective effect of Citrus aurantium peel extract(CAE) against apoptosis in cholestatic liver fibrosis induced by bile duct ligation in mice. Methods: Male ICR mice were divided to 5 groups: 1) Control group(Sham-operated mice), 2) Cholestatic liver injury group induced by bile duct ligation(BDL), 3) BDL mice treated with silymarin(200 mg/kg) for 4 weeks, 4) BDL mice treated with 50 mg/kg CAE for 4 weeks, 5) BDL mice treated with 200 mg/kg CAE for 4 weeks. Mice were sacrificed and liver fibrosis was evaluated by serum and hepatic tissue biochemistry tests and liver histopathological examination. Effects of CAE on inflammation and apoptosis gene regulation were investigated through real-time PCR. CAE effect on lipid metabolism related signaling was determined by western blot analysis. Results: In BDL mice, administration of CAE for 4 weeks markedly attenuated liver fibrosis based on histopathological alteration. Serum and hepatic tissue biochemistry results revealed that CAE(50 and 200 mg/kg) decreased the levels of alanine transaminase, aspartate transaminase, gamma glutamyl transferase, total bilirubin, nitric oxide, and thiobarbituric acid reactive substances. Real-time PCR and western blot analysis showed that CAE regulated inflammation, apoptosis, and lipid metabolism factors increased by BDL. Interleukin family, tumor necrosis factor α, and related apoptosis factors m RNA levels were increased by BDL treatment. However, these increases were suppressed by CAE administration. In addition, CAE effectively increased phosphorylation of AMPactivated protein kinase, nuclear factor E2-related factor 2, and related cytoprotective proteins. Conclusions: CAE can efficiently regulate BDL-induced liver injury with antioxidant, antiinflammatory, and antiapoptotic activities.     

Interaction between insulin-like growth factor binding protein-related protein 1 and trans-forming growth factor beta 1 in primary hepatic stellate cells

BACKGROUND:We previously showed that insulin-like growth factor binding protein-related protein 1(IGFBPrP1) is a novel mediator in liver fibrosis.Transforming growth factor beta 1(TGFβ1) is known as the strongest effector of liver fibrosis.Therefore,we aimed to investigate the detailed interaction between IGFBPrP1 and TGFβ1 in primary hepatic stellate cells(HSCs).METHODS:We overexpressed TGFβ1 or IGFBPrP1 and inhibited TGFβ1 expression in primary HSCs for 6,12,24,48,72,and 96 hours to investigate their interaction and observe the accompanying expressions of α-smooth muscle actin(α-SMA),collagen I,fibronectin,and phosphorylated-mothers against decapentaplegic homolog 2/3(p-Smad2/3).RESULTS:We found that the adenovirus vector encoding the TGFβ1 gene(Ad TGFβ1) induced IGFBPrP1 expression while that of α-SMA,collagen I,fibronectin,and TGFβ1 increased gradually.Concomitantly,Ad IGFBPrP1 upregulated TGFβ1,α-SMA,collagen I,fibronectin,and p-Smad2/3 in a time-dependent manner while IGFBPrP1 expression was decreased at 96 hours.Inhibition of TGFβ1 expression reduced the IGFBPrP1-stimulated expression of α-SMA,collagen I,fibronectin,and p-Smad2/3.CONCLUSIONS:These findings for the first time suggest the existence of a possible mutually regulation between IGFBPrP1 and TGFβ1,which likely accelerates liver fibrosis progression.Furthermore,IGFBPrP1 likely participates in liver fibrosis in a TGFβ1-depedent manner,and may act as an upstream regulatory factor of TGFβ1 in the Smad pathway.     

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.     

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.