Serum concentration of the aminoterminal procollagen type III peptide in the rat reflects early formation of connective tissue in experimental liver cirrhosis

A specific and sensitive radioimmunoassay for the rat aminoterminal procollagen type III peptide (PIIIP) was developed which allowed easy and sequential measurement of this peptide in the serum of individual animals. PIIIP in sera of 1-week-old rats was high (60 +/- 15.4 ng, 1 SD) falling to 15.7 +/- 4.3 ng/ml (1 SD) at 7 weeks and 6.7 +/- 2.6 ng/ml (1 SD) at 12 weeks of age. Adult animals (above 6 months of age) showed serum PIIIP levels in the narrow range of 2.5 +/- 2.33 ng/ml (2.5 SD). CCl4-induced liver damage in adult rats produced an elevated serum PIIIP (median 9.1; range 2.6-45.2 ng/ml) already after 2 weeks, rising to a mean of 33.8 ng/ml (range 22.0-47 ng/ml) after 6 weeks of continued CCl4-intoxication. In the same animals at 6 weeks, hepatic hydroxyproline was almost 5 times higher in the CCl4-group (mean 493.2; range 343.1-582.3 micrograms/100 mg dry weight) when compared with controls (109 +/- 14 micrograms/100 mg dry weight, 1 SD). These results are in complete analogy to those reported for PIIIP in sera of growing children, healthy human adults and patients with fibrogenic liver disease. Elevated serum PIIIP in rats with experimental liver fibrosis predicts the deposition of excess hepatic collagen. This novel serum test allows, for the first time, to assess altered PIIIP metabolism and hepatic fibrogenesis in individual animals as early as 2 weeks after the start of the experiment. It also reflects growth-related changes of type III collagen metabolism.     

Lipid peroxidation, stellate cell activation and hepatic fibrogenesis in a rat model of chronic steatohepatitis

BACKGROUND/AIMS: We explored the involvement of cell types, cytokines and lipid peroxidation in a rat dietary model of fibrosing steatohepatitis. METHODS: Male rats were fed a high fat diet deficient in methionine and choline (MCD) for up to 17 weeks. Whole liver, hepatocytes and non-parenchymal cells were analysed for reduced glutathione (GSH) levels, products of lipid peroxidation (thiobarbituric acid reactive substances, TBARS), liver injury, and fibrosis. RESULTS: MCD diet-fed rats developed hepatic steatosis at week 2 and focal necroinflammatory change by week 5, while pericellular fibrosis evolved and progressed between weeks 12 and 17. Collagen alpha(1)(1) gene expression was upregulated by week 5 and increased fivefold by week 17. Stellate cells were the unique source of collagen gene expression. TIMP-1 and -2 were increased at week 12. Livers of MCD diet-fed rats exhibited lowered levels of GSH and elevated TBARS. Hepatocytes were the source of lipid peroxidation, and mRNA levels for TGFbeta1 were increased only in this cell type. CONCLUSIONS: The MCD model of 'fibrosing steatohepatitis' replicates the histologic features of human steatohepatitis, and the sequence of steatosis, inflammatory cell injury and fibrogenesis. The temporal sequence is consistent with a concept for involvement of oxidative injury in inflammatory recruitment and pathogenesis of hepatic fibrogenesis.     

Role of hepatic vitamin A and lipocyte distribution in experimental hepatic fibrosis

ABSTRACT— Lipocytes are the major site of hepatic vitamin A storage, and they have been demonstrated to lose their vitamin A content in the process of hepatic fibrosis. To investigate the relationship between hepatic vitamin A content and the degree of hepatic fibrosis, we measured levels of retinyl palmitate and retinol in the CCl₄-induced fibrotic liver using high-performance liquid chromatography. We estimated hepatic collagen content using a spectrophotometric analysis with sirius red, and also by measuring hydroxyproline levels. Lipocytes were detected by an immunoperoxidase method with anti-desmin antibody, and were counted morphometrically through a Texture Analyzing System. A significant negative correlation was observed between the level of retinyl palmitate and collagen content (r = –0.64) as well as the hydroxyproline level (r = –0.69) in the CCl₄-induced fibrotic liver. In the process of fibrosis, hepatic retinol levels were elevated in association with a decrease in retinyl palmitate. In particular in the early stage of fibrosis, lipocytes increased remarkably in number in fibrotic areas in spite of a decrease in total hepatic vitamin A. The present study suggests that an increase in hepatic retinol as well as a decrease in retinyl palmitate may facilitate the process of hepatic fibrosis produced by lipocytes.     

Inhibitory effect of acyclic retinoid (polyprenoic acid) on hepatic fibrosis in CCl4-treated rats

A study was conducted to examine the inhibitory effect of acyclic retinoid (polyprenoic acid) on the development of hepatic fibrosis induced by CCl4 in rats. Oral administration of the compound brought about a significant reduction in both serum and tissue levels of immunoreactive prolyl hydroxylase, a key enzyme of collagen formation. The result indicated that the rate of collagen synthesis in the liver was decreased which was consistent with histological findings. Acyclic retinoid also decreased both AST and ALT activities in serum, demonstrating the reduction in hepatic parenchymal damage. This cytoprotective effect on parenchymal cells may be related, at least in part, to inhibition of hepatic fibrosis. No significant side effects were observed, despite a long-term administration of the acyclic retinoid. The present findings suggest the potential scope of therapy of hepatic fibrosis by retinoid.     

肌细胞增强因子2A与肝星状细胞活化关系的体内实验研究

背景：转录调控在肝星状细胞（HSC）活化过程中起重要作用,研究显示转录因子肌细胞增强因子2（MEF2）参与了HSC的活化过程。目的：探讨肝纤维化形成过程中MEF2家族成员MEF2A与HSC活化的关系。方法：实验开始时处死6只大鼠作为0周对照组,64只大鼠随机分为正常对照组和肝纤维化模型组。模型组大鼠皮下注射60％CCL（0．3ml／100g,每周2次）复制肝纤维化模型;正常对照组大鼠与模型组于相同条件下饲养,不予任何处理。造模开始后3、6、9、12周分批处死大鼠,取肝组织,实时荧光定量聚合酶链反应（PCR）检测MEF2AmRNA表达．蛋白质印迹法检测MEF2A蛋白和HSC活化标记物α-平滑肌肌动蛋白（α-SMA）表达,VanGieson染色定量分析肝内胶原含量。结果：正常肝组织中仅有少量MEF2AmRNA和蛋白表达;随着肝纤维化的形成,肝组织MEF2AmRNA和蛋白表达量逐渐增加（P〈0．05）,MEF2A与Q—SMA蛋白表达呈正相关（r=0．88,P〈0．05）。肝内胶原含量随肝纤维化的形成呈递增趋势（P〈0．01）。结论：MEF2A参与了CCl4。诱导的大鼠肝纤维化形成过程中HSC的活化和增殖。     

Alterations of mast cells and TGF-β1 on the silymarin treatment for CCl4-induced hepatic fibrosis

AIM: Silymarin is a potent antioxidant, antiinflammatory and anti-fibrogenic agent in the liver, which is mediated by alteration of hepatic Kupffer cell function, lipid peroxidation, and collagen production. Especially, in hepatic fibrogenesis, mast cells are expressed in chronic inflammatory conditions, and promote fibroblast growth and stimulate production of the extracellular matrix by hepatic stellate cells.METHODS: We examined the inhibitory mechanism of silymarin on CCl4-induced hepatic cirrhosis in rats. At 4, 8,and 12 wk, liver tissues were examined histopathologically for fibrotic changes produced by silymarin treatment.RESULTS: In the silymarin with CCl4-treated group,increase of hepatic stellate cells and TGF-β1 production were lower than in the CCl4-treated group at early stages.Additionally, at the late fibrogenic stage, expressions of TGF-β1 were weaker and especially not expressed in hepatocytes located in peripheral areas. Moreover, the number of mast cell in portal areas gradually increased and was dependent on the fibrogenic stage, but those of CCl4+silymarin-treated group decreased significantly.CONCLUSION: Anti-fibrotic and antiinflammatory effects of silymarin were associated with activation of hepatic stellate cells through the expression of TGF-β1 and stabilization of mast cells. These results suggest that silymarin prevent hepatic fibrosis through suppression of inflammation and hypoxia in the hepatic fibrogenesis.     

Cyclin E1 controls proliferation of hepatic stellate cells and is essential for liver fibrogenesis in mice

Liver fibrogenesis is associated with the transition of quiescent hepatocytes and hepatic stellate cells (HSCs) into the cell cycle. Exit from quiescence is controlled by E-type cyclins (cyclin E1 [CcnE1] and cyclin E2 [CcnE2]). Thus, the aim of the current study was to investigate the contribution of E-type cyclins for liver fibrosis in man and mice. Expression of CcnE1, but not of its homolog, CcnE2, was induced in fibrotic and cirrhotic livers from human patients with different etiologies and in murine wild-type (WT) livers after periodical administration of the profibrotic toxin, CCl(4) . To further evaluate the potential function of E-type cyclins for liver fibrogenesis, we repetitively treated constitutive CcnE1(-/-) and CcnE2(-/-) knock-out mice with CCl(4) to induce liver fibrosis. Interestingly, CcnE1(-/-) mice were protected against CCl(4) -mediated liver fibrogenesis, as evidenced by reduced collagen type I α1 expression and the lack of septum formation. In contrast, CcnE2(-/-) mice showed accelerated fibrogenesis after CCl(4) treatment. We isolated primary HSCs from WT, CcnE1(-/-) , and CcnE2(-/-) mice and analyzed their activation, proliferation, and survival in vitro. CcnE1 expression in WT HSCs was maximal when they started to proliferate, but decreased after the cells transdifferentiated into myofibroblasts. CcnE1(-/-) HSCs showed dramatically impaired survival, cell-cycle arrest, and strongly reduced expression of alpha smooth muscle actin, indicating deficient HSC activation. In contrast, CcnE2-deficient HSCs expressed an elevated level of CcnE1 and showed enhanced cell-cycle activity and proliferation, compared to WT cells. Conclusions: CcnE1 and CcnE2 have antagonistic roles in liver fibrosis. CcnE1 is indispensable for the activation, proliferation, and survival of HSCs and thus promotes the synthesis of extracellular matrix and liver fibrogenesis. (HEPATOLOGY 2012;56:1140-1149).     

Effects of estradiol on liver estrogen receptor-alpha and its mRNA expression in hepatic fibrosis in rats

AIM:Estradiol treatment regulates estrogen receptor (ER) level in normal rat liver.However,little information is available concerning the role of estrogen in regulating liver ER in hepatic fibrosis in rats.The present study was conducted to determine whether estradiol treatment in CCl4-induced liver fibrosis of female and ovariectomized rats altered liver ERα and its mRNA expression,and to investigate the possible mechanisms.METHODS:Seventy female rats were divided into seven groups with ten rats in each. The ovariectomy groups were initiated with ovariectomies and the sham operation groups were initiated with just sham operations.The CCl4 toxic fibrosis groups received 400mL/L CCI4 subcutaneously at a dose of 2 mL/kg twice weekly.Estrogen groups were treated subcutaneously with estradiol 1mg/kg, the normal control group and an ovariectomy group received injection of peanut oil vehicle twice weekly.At the end of 8 weeks,all the rats were killed to detect their serum and hepatic indicators,their hepatic collagen content, and liver ER and ER mRNA expression.RESULTS: Estradiol treatment in both ovariectomy and sham ovariectomy groups reduced liver levels of ALT (from 658±220nkat/L to 311±146nkat/L and 540±252nkat/L to 314±163nkat/L,P<0.05) and AST (from 697±240nkat/L to 321±121nkat/L and 631±268nkat/L to 302±153nkat/L,P<0.05),increased serum nitric oxide (NO) level (from 53.7±17.1μmol/L to 93.3±4.2μmol/L and 55.3±3.1μmol/Lto 87.5±23.6μmol/L, P<0.05) and hepatic nitric oxide synthase (NOS) activity (from 1.73±0.71KU/g to 2.49±1.20KU/g and 1.65±0.46KU/g to 2.68±1.17KU/g, P<0.05),diminished the accumulation of hepatic collagen,decreased centrolobular necrotic areas as well as the inflammatory reaction in rats subjected to CCl4. The positive signal of ER and ER mRNA distributed in parenchymal and non-parenchymal hepatic cells,especially near the hepatic centrolobular and periportal areas.Ovariectomy decreased ER level (from 10.2±3.2 to 4.3±1.3) and ER mRNA expression (from 12.8±2.1 to 10.9±1.3) significantly (P<0.05). Hepatic ER and ER mRNA concentrations were elevated after treatment with estradiol in both ovariectomy (15.8±2.4, 20.8±3.1) and sham ovariectomy(18.7±3.8, 23.1±3.7) fibrotic groups (P<O.05).CONCLUSION: The increase in hepatic ER and mRNA expression may be part of the molecular mechanisms underlying the suppressive effect of estradiol on liver fibrosis induced by CCI4 administration.     

Alterations of mast cells and TGF-β1 on the silymarin treatment for CCl4-induced hepatic fibrosis

AIM: Silymarin is a potent antioxidant, antiinflammatory and anti-fibrogenic agent in the liver, which is mediated by alteration of hepatic Kupffer cell function, lipid peroxidation, and collagen production, Especially, in hepatic fibrogenesis, mast cells are expressed in chronic inflammatory conditions, and promote fibroblast growth and stimulate production of the extracellular matrix by hepatic stellate cells. METHODS: We examined the inhibitory mechanism of silymarin on CCl4-induced hepatic cirrhosis in rats. At 4, 8, and 12 wk, liver tissues were examined histopathologically for fibrotic changes produced by silymarin treatment. RESULTS: In the silymarin with CCl4-treated group, increase of hepatic stellate cells and TGF-β1 production were lower than in the CCl4-treated group at early stages. Additionally, at the late fibrogenic stage, expressions of TGF-β1 were weaker and especially not expressed in hepatocytes located in peripheral areas. Moreover, the number of mast cell in portal areas gradually increased and was dependent on the fibrogenic stage, but those of CCl4+silymarin-treated group decreased significantly. CONCLUSION: Anti-fibrotic and antiinflammatory effects of silymarin were associated with activation of hepatic stellate cells through the expression of TGF-β1 and stabilization of mast cells, These results suggest that silymarin prevent hepatic fibrosis through suppression of inflammation and hypoxia in the hepatic fibrogenesis.     

Filtrate of fermented mycelia from Antrodia camphorata reduces liver fibrosis induced by carbon tetrachloride in rats

AIM: To investigate the effects of filtrate of fermented mycelia from Antrodia camphorata (FMAC) on liver fibro-sis induced by carbon tetrachloride (CCI4) in rats. METHODS: Forty Wistar rats were divided randomly into control group and model group. All model rats were given 200 mL/L CCI4 (2 mL/Kg, po) twice a week for 8 wk. Four weeks after CCI4 treatment, thirty model rats were further divided randomly into 3 subgroups: CCI4 and two FMAC subgroups. Rats in CCI4 and 2 FMAC subgroups were treated with FMAC 0, 0.5 and 1.0 g/kg, daily via gastrogavage beginning at the fifth week and the end of the eighth week. Spleen weight, blood synthetic markers (albumin and prothrombin time) and hepatic malondial-dehyde (MDA) and hydroxyproline (HP) concentrations were determined. Expression of collagen I, tissue inhibitor of metalloproteinases (TIMP)-1 and transforming growth factorβ1 (TGF-β1) mRNA were detected by RT-PCR. Histochemical staining of Masson's trichrome was performed. RESULTS: CCI4 caused liver fibrosis, featuring increased prothrombin time, hepatic MDA and HP contents, and spleen weight and decreased plasma albumin level. Compared with CCI4 subgroup, FMAC subgroup (1 g/kg) significantly decreased the prothrombin time (36.7±7.2 and 25.1±10.2 in CCI4 and FMAC groups, respectively, P<0.05) and increased plasma albumin concentration (22.7±1.0 and 30.7±2.5 in CCI4 and FMAC groups, respectively, P< 0.05). Spleen weight was significantly lower in rats treated with CCI4 and FMAC (1 g/kg) compared to CCI4 treated rats only (2.7±0.1 and 2.4±0.2 in CCI4 and FMAC groups, respectively, P<0.05). The amounts of hepatic MDA and HP in CCI4±FAMC (1 g/kg) subgroup were also lower than those in CCI4 subgroup (MDA: 3.9±0.1 and 2.4±0.6 in CCI4 and CCI4 FMAC groups, respectively, P< 0.01; HP: 1730.7±258.0 and 1311.5±238.8 in CCI4 and CCI4 FMAC groups, respectively, P<0.01). Histologic examinations showed that CCI4 FMAC subgroups had thinner or less fibrotic septa than CCI4 group. RT-PCR analysis indicated that FMAC (1 g/kg) reduced mRNA levels of collagen I, TIMP-1 and TGF-β1 (collagenⅠ: 5.63±2.08 and 1.78±0.48 in CCI4 and CCI4 FMAC groups, respectively, P<0.01; TIMP-1: 1.70±0.82 and 0.34±0.02 in CCI4 and CCI4 FMAC groups, respectively, P<0.01; TGF-β1:38.03±11.9 and 4.26±2.17 in CCI4 and CCI4 FMAC groups, respectively, P<0.01) in the CCI4-treated liver. CONCLUSION: It demonstrates that FMAC can retard the progression of liver fibrosis induced by CCI4 in rats.     

Effect of Oxymatrine on the TGFbeta-Smad signaling pathway in rats with CCl4-induced hepatic fibrosis

AIM： To explore the anti-fibrotic effect of Oxymatrine on CCl4-induced liver fibrosis in rats and its modulation on the TGFbeta-Smad signaling pathway. METHODS： One hundred healthy male SD rats were randomly divided into three groups： normal group （n = 20）, treatment group of Oxymatrine （n = 40） and CCh-induced fibrosis group （n = 40）. Experimental hepatic fibrosis was induced by subcutaneous injection of carbon tetrachloride （CCh soluted in liquid paraffin with the concentration of 300 g/L, the dosage of injection was 3 mL/kg, twice per week for 8 wk）. The treated rats received Oxymatrine via celiac injection at a dosage of 10 mg/kg twice a week at the same time. The deposition of collagen was observed with H＆E and Masson staining. The concentration of serum TGF-β1 was assayed with ELISA. The gene expression of Smads and CBP （CREB binding protein） was detected with in situ hybridization （ISH） and immunohistochemistry （IH）, respectively. All the experimental figures were scanned and analyzed with special figure-analysis software. RESULTS： A significant reduction of collagen deposition and rearrangement of the parenchyma was noted in the liver tissue of Oxymatrine-treated rats. The semi- quantitative histological scores （2.43 ± 0.47 μm^2 vs 3.76 ±0.68, P 〈 0.05） and average area of collagen/in those rats were significantly decreased when compared with hepatic cirrhosis model rats （94.41 ± 37.26 μm^2 vs 290.86 ± 89.37 μm^2, P 〈 0.05）. The gene expression of Smad 3 mRNA was considerably decreased in the treated animals. The A value of Smad 3 mRNA was lower in the treated rats than the model rats （0.034 ± 0.090 vs 0.167 ± 0.092, P 〈 0.05）. Contrarily, the A value of Smad 7 mRNA was increased considerably in the treated animals （0.175 ± 0.065 vs 0.074 vs 0.012, P 〈 0.05）. There was an obvious decrease in the expression of CBP mRNA in treated rats as illuminated by a reduction of its A value when compared with model rats （0.065±0.049 vs 0.235 ?     

Hepatic fibrogenesis]

In acute injury, liver recovers completely without any scarring change or complication. However, large portion of liver is changed into fibrotic state by excessive production of extracellular matrix (ECM) under chronic injury. Excessive production of ECM results in hepatic fibrosis and repeated process of hepatic fibrosis progress into liver cirrhosis. Liver cirrhosis is an irreversible and terminal state of chronic liver disease and one of the major causes of death in Korea. To block the progression to liver cirrhosis, various studies in the field of virology and immunology have been proceeded. Recently, studies on the hepatic fibrogenesis have progressed with the development of molecular biology. Hepatic stellate cells (HSC) play a key role in the pathogenesis of hepatic fibrosis by producing ECM. The degree of hepatic fibrosis depends on the proliferation and activation of HSC and increased net production of collagen. Therefore, inhibition of HSC activation is one of the main ways to block the progression of hepatic fibrosis. Many kinds of factors such as oxidative stress, acetaldehyde, ascorbic acid, transforming growth factor-beta (TGF-beta) and carbon tetrachloride (CCl4) have been reported to activate HSC and stimulate collagen gene expression. Although there are no definite and effective antifibrogenic agents, possible candidates are antioxidants, interferon, retinoids such as beta-carotene, flavonoids, renin-angiotensin system inhibitors and peroxisome proliferator activated receptor-gamma (PPAR-gamma) agonists. We tried to evaluate the charateristics of HSC in order to develop agents that inhibit hepatic fibrogenesis.     

Contribution of immune response to the hepatic fibrosis induced by porcine serum

To investigate whether hepatic fibrosis induced by porcine serum in rats is caused by an immune reaction to porcine serum, rats that were immunologically tolerant exclusively to porcine serum were subjected to the repeated injection of porcine serum over a long period. This porcine serum-tolerant group consisted of 15 Wistar rats that had been injected intraperitoneally with porcine serum twice a week from the first postnatal day for 18 weeks. The control group consisted of 16 Wistar rats, aged 8 weeks, that were injected intraperitoneally with porcine serum twice a week for 10 weeks. Livers were fixed and examined by light microscopy. The serum of each rat was subjected to indirect enzyme-linked immunosorbent assay (ELISA) to measure the level of antibody to porcine albumin. In addition, immunohistochemical staining for ED1 was performed on untreated normal and porcine serum-induced fibrotic rat livers to examine the distribution of macrophages and their precursors, the monocytes. All rats in the tolerant group showed an extremely low antibody level (x = 68.27 +/- 4.53), and none (0/15) developed hepatic fibrosis. The majority of rats in the control group showed a very high antibody level (x = 1242.19 +/- 201.15); 75 percent (12/16) developed hepatic fibrosis. Data indicate that, despite the prolonged, repeated injections of porcine serum, if an immune response to porcine serum does not occur, the rats do not develop hepatic fibrosis. The porcine serum-tolerant rats developed hepatic fibrosis after 4 weeks of CCl4 treatment, indicating that injection of porcine serum into neonatal rats did not cause anergy of fibrogenesis, thereby preventing the animal from developing hepatic fibrosis. In normal rat liver, ED1-positive cells, which include nearly all Kupffer cells, were located pre-dominantly in the periportal area. In fibrotic rat liver, ED1-positive cells aggregated prominently in the newly formed and advanced connective tissue septa developed mainly between the neighboring central veins, and in fibrotic parts of the liver capsule. Aggregation of ED1-positive cells was rarely observed in nonfibrotic parts of the liver capsule. The difference between normal and fibrotic rat liver in distribution of EDl-positive cells suggests an involvement of macrophages in fibrogenesis and septum formation. In conclusion, our study showed a significant contribution by the immune response to porcine serum antigens leading to porcine serum-induced rat hepatic fibrosis--processes in which macrophages may be important. This study may lead to an understanding of the mechanism responsible for this form of experimental hepatic fibrosis. (Hepatology 1996 Apr;23(4):811-7)     

Effects of cytokines on carbon tetrachloride-induced hepatic fibrogenesis in rats

AIM: To observe the possible effects of transforming growth factor (TGF) β1, interleukin (IL)-6, tumor-necrosis factor (TNF) α and IL-10 on experimental rat hepatic fibrosis. METHODS: One hundred SD rats were divided randomly into the three groups. Control group received intraperitoneal injection of saline (2 ml-kg^-1), twice a week. Fibrogenesis group was injected intraperitoneally with 50% carbon tetrachloride (CCI4) (2 ml-kg^-1) twice a week. Fibrosisintervention group was given IL-10 at a dose of 4 μg-kg^-1 20 minutes before CCI4 administration from the third week.At the fifth, seventh, and ninth weeks, 7 to 10 rats in each group were sacrificed to collect serum. Levels of TGF-β1,TNF-α, IL-6 and IL-10 were determined by enzyme-linkedimmunosorbent assay (ELISA). The liver tissues were taken for routine histological examination. RESULTS: Hepatic fibrosis was developed with the injection of CCI4. Values of the circulating TGFβ, TNFα, IL-6 and IL-10 in the control group were 25.495.56 ng.L^-1, 15.18&#177;3.83ng.L^-1, 63.64&#177;13.03 ng.L-^1 and 132.90&#177;12.13 ng.L^-1,respectively. Their levels in the CCI4-intoxication group were 31.13&#177;6.41 ng.L^-1, 18.91&#177;5.31 ng.L^-1, 89.08&#177;25.39 ng.L^-1 and 57.63&#177;18.88 ng.L^-1, respectively, and those in the IL-10-intervention group were 26.11&#177;5.32 ng.L^-1,13.99&#177;1.86 ng.L^-1,74.71&#177;21.15 ng.L^-1 and 88.19&#177;20.81 ng.L^-1, respectively. A gradual increase was observed in the levels of TGFβ1, TNFα and IL-6 during hepatic fibrogenesis. These changes were pardally reversed by simultaneous administration of IL-10. The histological parameters, characterized by CCl4-intoxificatJon,also seemed to be improved with IL-10 treatment, the collagen production was reduced at the ninth week and the histological activity index was decreased from 7.9&#177;1.2 to 4.7&#177;0.9. CONCLUSION: TGFβ1, TNFα and IL-6 may play important roles during CCI4-induced hepatic fibrogenesis, and IL-10 may counterbalance their effects.     

Reversal of liver fibrosis in aryl hydrocarbon receptor null mice by dietary vitamin A depletion

Aryl hydrocarbon receptor (AHR)-null mice display a liver fibrosis phenotype that is associated with a concomitant increase in liver retinoid concentration, tissue transglutaminase type II (TGaseII) activity, transforming growth factor beta (TGF beta) overexpression, and accumulation of collagen. To test the hypothesis that this phenotype might be triggered by the observed increase in liver retinoid content, we induced the condition of retinoid depletion by feeding AHR-null mice a vitamin A- deficient diet with the purpose to reverse the phenotype. Liver retinoid content decreased sharply within the first few weeks on the retinoid-deficient diet. Analysis of TGF beta 1, TGF beta 2, and TGF beta 3 expression revealed a reduction to control levels in the AHR -/- mice accompanied by parallel changes in TGaseII protein levels. In addition, we observed an increase in the TGF beta receptors, TGF beta RI and TGF beta RII, as well as in Smad4, and their reduction to wild-type mouse liver levels in AHR -/- mice fed the retinoid-deficient diet. Reduction of peroxisomal proliferator-activated receptor gamma (PPAR gamma) messenger RNA (mRNA) and protein levels in AHR -/- mice was consistent with the presence of hepatic stellate cell (HSC) activation and liver fibrosis. Vitamin A deficiency normalized PPAR gamma expression in AHR -/- mice. In conclusion, livers from AHR -/- mice fed the vitamin A-deficient diet showed a decrease in collagen deposition, consistent with the absence of liver fibrosis.     

Animal experiment and clinical study of effect of gamma-interferon on hepatic fibrosis

AIM To evaluate the antifibrotic effect ofdifferent doses of recombinant human Gamma-Interferon (IFN-γ) in two rat models of hepaticfibrosis, and to observe its effect on moderatechronic hepatitis B virus fibrosis.METHODS Hepatic fibrosis was successfullyinduced in 150 and 196 rats by subcutaneousinjection of carbon tetrachloride (CCl_4) andintraperitoneal injection of dimethylnitrosamine(DMN), respectively. Each of the two modelgroups was divided into: ① fibrotic modelgroup; ② colchicine treatment group (0.1 mg/kg/day, gastrogavage for 8 weeks); ③ high-dose IFN-γ group (15 MU/kg per day, i.m. for 8weeks); ④ medium-dose IFN-γ group (5 MU/kgdaily, i.m. for 8 weeks); and ⑤ low-dose IFN-γgroup (1.67 MU/kg daily, i.m. for 8 weeks).Another group of 10 rats without any treatmentwas used as normal controls. At the end of theexperiment, semi-quantitative histopathologicalscores of inflammation and fibrosis, liversmooth muscle actin (α-SMA) expression level,liver hydroxyl proline content and serumhyaluronic acid levels were compared. And 47medium chronic hepatitis B viral fibrosispatients were studied. They were given IFN-γtreatment, 100MU/day i,m. for the first threemonths and 100MU qod i.m. for the next sixmonths. Semi-quantitative pathological scoresof inflammation and fibrosis and serum hepaticfibrosis indices were compared within the 9months.RESULTS In animal experiment, thepathological fibrosis scores and liver hydroxylproline content were found to be significantly lower in rats treated with different doses of IFN-γ as compared with rats in fibrotic model groupinduced by either CCl_4 or DMN, in a dose-dependent manner. For CCl_4-induced model,pathological fibrosis scores in high, medium andlow doses IFN-γ groups were 5. 10±2.88, 7.70±3.53 and 8.00±3.30, respectively, but the scorewas 14.60±7.82 in fibrotic model group.Hydroxyl proline contents were 2.83±1.18, 3.59±1.22 and 4.80±1.62, in the three IFN-γgroups, and 10.01±3.23 in fibrotic model group.The difference was statistically significant(P<0.01). Similar results were found in DMN-induced model. Pathological fibrosis scoreswere 6.30±0.48, 8.10±2.72 and 8.30±2.58, inhigh, medium and low doses IFN-γ groups, and12.60±3.57 in fibrotic model group. Hydroxylproline contents were 2.72±0.58, 3.14±0.71and 3.62±1.02, in the three IFN-γ groups, and12.79±1.54 in fibrotic model group. Thedifference was statistically significant(P<0.01). Serum hepatic fibrosis indicesdecreased significantly in the 47 patients afterIFN-γ treatment (HA: 433.38±373.00 vs 281.57±220.48; LN: 161.22±41.02 vs 146.35±44.67;PCⅢ: 192.59±89.95 vs 156.98±49.22; C-Ⅳ:156.30±44.01 vs 139.14±34.47) and thedifferences between the four indices weresignificant (P<0.05). Thirty-three patientsreceived two liver biopsies, one before and oneafter IFN-γ treatment. In thirty of 33 patientsIFN-γ had better effects according to semi-quantitative pathological scores (8.40±5.83 vs5.30±4.05, P<0.05).CONCLUSION All the three doses of IFN-γ areeffective in treating rat liver fibrosis induced byeither CCl_4 or DMN, the higher the dose, thebetter the effect. And IFN-γ is effective forpatients with moderate chronic hepatitis B viralfibrosis.     

Osteopontin expression in normal and fibrotic liver. altered liver healing in osteopontin-deficient mice

BACKGROUND/AIMS: Osteopontin has been implicated in numerous physiopathological events. Osteopontin expression in normal and fibrotic liver and liver fibrogenesis in osteopontin-deficient mice were studied. METHODS: Fibrosis was induced in mice and rats by carbon tetrachloride (CCl4) treatment or bile duct ligation. The liver was used for conventional histology, osteopontin immunohistochemistry and in situ hybridization, or protein and RNA extraction. In mice, necrotic areas and fibrosis were evaluated by quantitative image analysis. RESULTS: In normal liver, osteopontin mRNA expression was very low. After CCl4 treatment or bile duct ligation, osteopontin mRNA expression was increased. Osteopontin was expressed by biliary epithelial cells in normal and fibrotic liver. Soon after the beginning of the CCl4 treatment, osteopontin was also present in inflammatory cells of the necrotic areas. In osteopontin-deficient mice, necrotic areas after a single dose of CCl4, and fibrosis after chronic CCl4 treatment were significantly increased as compared with wild-type treated mice. CONCLUSIONS: Our results show that osteopontin expression increases during liver fibrogenesis. Furthermore, osteopontin-deficient mice were more susceptible to CCl4 treatment, displaying more necrosis during the initial steps (probably due to a deficiency in nitric oxide production) and more fibrosis thereafter. The increase in osteopontin expression observed during liver fibrogenesis may play a protective role.