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.     

Inhibitory effects of prostaglandin E_1 on activation of hepatic stellate cells in rabbits with schistosomiasis

BACKGROUND: Liver fibrosis is the result of an imbalance between synthesis and degradation of extracellular matrix proteins of the liver. At the cellular and molecular levels, this progressive process is mainly characterized by activation of hepatic stellate cells (HSCs). Schistosoma japonica is one of the most prevalent causes of liver fibrosis in China. It is characterized by hepatocyte damage, inflammation, and chronic parasite egg-induced granuloma formation leading to fibrosis. This study aimed to investigate the inhibitory effects of prostaglandin E1 (PGE1) on activation of HSCs and the alteration of type Ⅰ and Ⅲ collagen in rabbits with schistosomiasis. The study may promote the clinical application of praziquantel and PGE1 as a combined therapy to reverse hepatic fibrosis caused by schistosomiasis. METHODS: Rabbits were percutaneously infected with cercaria of S. japonicum. Seven rabbits were subjected to intravenous injections of PGE1 (2.5 μg/kg daily) from days 60 to 120 after infection. The ultrastructural changes in activated HSCs were observed under transmission electron microscopy. The expression of α-smooth muscle actin (α-SMA) was detected by immunohistochemistry. Fibril-forming collagens were detected by picrosirius staining. RESULTS: Activation of HSCs was a characteristic alteration in schistosome-induced hepatic fibrosis. The expression of contraction-related α-SMA and thecontent of collagens were increased. Exogenous PGE1 markedly inhibited the activation of HSCs and reduced the expression of α-SMA around the hepatic sinusoids (P<0.01). The contents of type Ⅰ and Ⅲ collagens were significantly attenuated. The ratio of staining area to the whole field (10×3.3) under a polarized light microscope in the untreated and treated groups was 37.25±9.71 vs. 13.38±4.24 (P<0.01) and 9.66±3.52 vs. 6.23±1.81 (P<0.05), respectively. CONCLUSIONS: Activation of HSCs may play a key role in the progress of schistosome-induced hepatic fibrosis. PGE1 effectively protects rabbit liver from fibrosis, at least in part by inhibiting the activation of HSCs.     

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.     

Morphological and serum hyaluronic acid, laminin and type Ⅳ collagen changes in dimethylnitrosamine-induced hepatic fibrosis of rats

AIM: To study the morphological and serum hyaluronic acid (HA), laminin (LN), and type Ⅳ collagen changes in hepatic fibrosis of rats induced by dimethylnitrosamine (DMN). METHODS: The rat model of liver fibrosis was induced by DMN. Serum HA, type Ⅳ collagen, and LN were measured by ELISA. The liver/weight index and morphological changes were examined under electron microscope on d 7, 14, 21, and 28 by immunohistochemical alpha smooth muscle actin α-SMA staining as well as Sirius-red and HE staining. RESULTS: The levels of serum HA, type Ⅳ collagen and LN significantly increased from d 7 to d 28 (P = 0.043). The liver/weight index increased on d 7 and decreased on d 28. In the model group, the rat liver stained with HE and Sirius-red showed evident hemorrhage and necrosis in the central vein of hepatic 10 lobules on d 7. Thin fibrotic septa were formed joining central areas of the liver on d 14. The number of α-SMA positive cells was markedly increased in the model group. Transitional hepatic stellate cells were observed under electron microscope. All rats in the model group showed micronodular fibrosis in the hepatic parenchyma and a network of α-SMA positive cells. Typical myofibroblasts were embedded in the core of a fibrous septum. Compared to the control group, the area-density percentage of collagen fibrosis and pathologic grading were significantly different in the model group (P<0.05) on different d (7, 14, and 28). The area-density percentage of collagen fibrosis in hepatic tissue had a positive correlation with the levels of serum HA, LN, and type Ⅳ collagen. CONCLUSION: The morphological and serum HA, type Ⅳ collagen, and LN are changed in DMN-induced liver fibrosis in rats.     

Effects of c-myb antisense RNA on TGF-β1 and α1-Ⅰ collagen expression in cultured hepatic stellate cells

AIM: To investigate the effects of c-myb antisense RNA on cell proliferation and the expression of c-myb, TGF-β1 and α1-Ⅰ collagen in cultured hepatic stellate cells (HSC) from rats.METHODS: Recombinant retroviral vector of c-myb antisense gene (pDOR-myb) was constructed, and then transfected into retroviral package cell line PA317 by means of DOTAP.The pseudoviruses produced from the resistant PA317 cells were selected with G418 to infect HSCs isolated from rat livers. The cell proliferation was measured by 3-[4,5-Dimethylthiazolzyl]-2, 5-diphenyl tetrazo-dium bromide (MTT) method.The expression of c-myb, α1-Ⅰ collagen and TGF-β1 rnRNA, and c-myb protein in HSCs was detected with semi-quantitive reverse transeription-polymerase chain reaction (RT-PCR) and Western-blot respectively.RESULTS: HSCs from rats were isolated successfully with the viability &gt;98%. In the pDOR-myb infected HSCs, the cmyb protein expression, cell proliferation,and α1-Ⅰ collagen and TGF-β1 mRNA expression were repressed significantly compared with their corresponding control groups (P&lt;0.01).CONCLUSION: c-myb plays a key role in activation and proliferation of HSC. c-myb antisense RNA can inhibit cell proliferation, α1-Ⅰ collagen and TGF-β1 mRNA expression,suggesting that inhibition of c-myb gene expression might be a potential way for the treatment of liver fibrosis.     

Effect of bone marrow mesenchymal stem cells on the Smad expression of hepatic fibrosis rats

Objective:To investigate the impact of bone marrow mesenchymal stem cells on Smad expression of hepatic fibrosis rats.Methods:A total of 48 adult female SD rats were randomly divided into three groups,normal control group(n=10),observation group(n=19)with liver fibrosis model rats injected with BMSCs cells:model group(n=19),with liver fibrosis model rats injected with physiological saline.Serum index,TGF-β1 and Smad expression were detected.Results:TypeⅢprocollagen,Ⅳcollagen,hyaluronic acid,laminin levels of observation group were significantly lower than those of model group(P0.05).The content and expression of TGF-β1in serum and liver tissue of observation group were significantly lower than those of model group(P0.05).Compared with normal control group,the Smad3,Smad4 mRNA and protein expression of model group were significantly increased,the Smad7 mRNA and protein expression were significantly reduced(P0.05).Compared with model group.Smad3,Smad4 mRNA and protein expression of observation group were significantly reduced,and Smad7 mRNA expression were significantly increased(P0.05).Conclusions:BMSCs can regulate Smad expression to some extent,and reduce the degree of liver fibrosis.     

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.     

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.     

Effect of Astragalus complanatus flavonoid on anti-liver fibrosis in rats

AIM: To observe the anti-liver fibrosis effect of Astragalus complanatus flavonoids(ACF) in rats. METHODS: The liver fibrosis model in rats was established by injecting interperitoneally 0.2 mL/100 g 0.5% dimethylnitrosamine, thrice a week. Meanwhile, the rats were administered ACF(30, 60, 120 mg/kg) or colchicine(0.1 mg/kg) once a day for 1 mo. Serum N-propeptide of type Ⅰ procollagen(PINP) and type Ⅲ procollagen(PIIINP) was measured using ELISA. Malondialdehyde(MDA) and superoxide dismutase(SOD) in hepatic tissue were evaluated. Matrix metal protease-1(MMP-1) mRNA expression was assayed by RT-PCR and the protein expression of tissue inhibitor of metal protease-1(TTMP-1) was analyzed by immunohistochemistry. RESULTS: In the ACF groups, SOD activity increased and MDA content decreased in comparison to the liver fibrosis model group. The serum PINP and PIIINP contents in ACF-2 and -3 group decreased compared to those in model group. In ACF-2 and -3 group, the expression of MMP-1 mRNA increased significantly and the protein expression of TTMP-1 decreased compared to that in model group. CONCLUSION: The antifibrotic mechanisms of ACF are associated with its influence on lipid peroxidation and collagen synthesis and degradation.     

Morin enhances hepatic Nrf2 expression in a liver fibrosis rat model

AIM To investigate whether morin can reduce hepatic fibrosis by activating the NF-E2-related factor 2(Nrf2) signaling pathway.METHODS Twenty male Sprague-Dawley rats were randomly divided into four groups: control group, morin group, carbon tetrachloride(CCl4) group, and morin + CCl4 group. Rats in both the CCl4 and morin + CCl4 groups were injected intraperitoneally with CCl4 at a dose of 2 mL/kg twice a week. Rats in both the morin and morin + CCl4 groups were treated orally with morin at a dose of 50 mg/kg twice a week. Control rats were treated with vehicle only twice a week. At the end-point of the 8 wk of the experimental period, serum AST, ALT, and ALP were measured, and the liver specimenswere obtained for pathological assessment. Real-time PCR and Western blot methods were used to analyze the expression of α-smooth muscle actin(α-SMA), collagen Ⅰ, collagen Ⅲ, Nrf2, heme oxygenase(HO-1), and quinone oxidoreductase 1(NQO1) using frozen liver specimens.RESULTS Morin-treated rats in the morin + CCl4 group had less hyperplasia of fiber tissue, minimal inflammatory cells, and less body weight loss with favorable liver enzyme measurements compared to rats treated with CCl4 only. Additionally, morin-treated rats had significantly lower m RNA and protein expression of α-SMA, collagen Ⅰ, and collagen Ⅲ, but significantly higher m RNA and protein expression of Nrf2, HO-1, and NQO1 compared to rats treated with CCl4 only(P 0.05).CONCLUSION Morin could play a protective role by inducing the expression of Nrf2 and its downstream antioxidant factors(HO-1 and NQO1) and reducing the expression of α-SMA, collagen Ⅰ, and collagen Ⅲ in CCl4-induced liver fibrosis rats.     

Regulation of activin receptor-interacting protein 2 expression in mouse hepatoma Hepa1-6 cells and its relationship with collagen type Ⅳ

AIM: To investigate the regulation of activin receptor-interacting protein 2 (ARIP2) expression and its possible relationships with collagen type Ⅳ (collagen Ⅳ) in mouse hepatoma cell line Hepal-6 cells. METHODS: The ARIP2 mRNA expression kinetics in Hepal-6 cells was detected by RT-PCR,and its regulation factors were analyzed by treatment with signal transduction activators such as phorbol 12-myristate 13-acetate (PMA),forskolin and A23187. After pcDNA3-ARIP2 was transfected into Hepal-6 cells,the effects of ARIP2 overexpression on activin type Ⅱ receptor (ActRⅡ) and collagen Ⅳ expression were evaluated. RESULTS: The expression levels of ARIP2 mRNA in Hapel-6 cells were elevated in time-dependent manner 12 h after treatment with activin A and endotoxin LPS,but not changed evidently in the early stage of stimulation (2 or 4 h). The ARIP2 mRNA expression was increased after stimulated with signal transduction activators such as PMA and forskolin in Hepal-6 cells,whereas decreased after treatment with A23187 (25.3% ± 5.7% vs 48.1% ± 3.6%,P < 0.01). ARIP2 overexpression could remarkably suppress the expression of ActRⅡA mRNA in dose-dependent manner,but has no effect on ActRⅡB in Hepal-6 cells induced by activin A. Furthermore,we have found that overexpression of ARIP2 could inhibit collagen Ⅳ mRNA and protein expressions induced by activin A in Hapel-6 cells. CONCLUSION: These findings suggest that ARIP2 expression can be influenced by various factors. ARIP2 may participate in the negative feedback regulation of signal transduction in the late stage by affecting the expression of ActRⅡA and play an important role in regulation of development of liver fibrosis induced by activin.     

Blockage of transforming growth factor β receptors prevents progression of pig serum-induced rat liver fibrosis

AIM: To test the hypothesis that introduction of antisense TβR Ⅰ and TβR Ⅱ eukaryotic expressing plasmids into a rat model of immunologically induced liver fibrosis might block the action of TGF-β1 and halt the progression of liver fibrosis. METHODS: RT-Nest-PCR and gene recombination techniques were used to construct rat antisense TβR Ⅰ and TβR Ⅱ recombinant plasmids which could be expressed in eukaryotic cells. The recombinant plasmids and empty vector (pcDNA3) were encapsulated by glycosyl-poly-L-lysine and then transducted into rats of pig serum-induced liver fibrosis model. Expression of exogenously transfected gene was assessed by Northern blot, and hepatic expressions of TβR Ⅰ and TβR Ⅱ were evaluated by RT-PCR and Western blot.We also performed ELISA for serum TGF-β1, hydroxyproline of hepatic tissues, immunohistochemistry for collagen types Ⅰ and Ⅲ, and VG staining for pathological study of the liver tissues. RESULTS: The exogenous antisense TβR Ⅰ and TβR Ⅱ plasmids could be well expressed in vivo, and block mRNA and protein expression of TβR Ⅰ and TβR Ⅱ in the fibrotic liver at the level of mRNA respectively. These exogenous plasmid expressions reduced the level of TGF-β1 (antisense TβR Ⅰ group 23.998+3.045 ng/mL, antisense TβR Ⅱ group 23.156+3.131 ng/mL, disease control group 32.960+3.789 ng/mL; F-=-38.19, 36.73, P&lt;0.01). Compared with disease control group, the contents of hepatic hydroxyproline (antisense TβR Ⅰ group 0.169+0.015 mg/g liver, antisense TβR Ⅱ group 0.167+0.009 mg/g liver, disease control group 0.296+0.026 mg/g liver; F=14.39, 15.48, P&lt;0.01) and the deposition of collagen types Ⅰ and Ⅲ decreased in the two antisense treatment groups(antisense TβR Ⅰ group, collagen type Ⅰ 669.90+50.67, collagen type Ⅲ 657.29+49.48; antisense TβR Ⅱ group, collagen type Ⅰ 650.26+51.51, collagen type Ⅲ 661.58+55.28; disease control group, collagen type I 1209.44+116.60, collagen type Ⅲ 1175.14+121.44; F=15.48 to 74.89, P&lt;0.01). Their expression also improved the pathologic classification of liver fibrosis models (compared with disease control group, X^2=17.14, 17.24, P&lt;0.01). No difference was found in the level of TGF-β1, the contents of hepatic hydroxyproline and collagen types Ⅰ and Ⅲ and pathologic grade between pcDNA3 control group and disease control group or between the two antisense treatment groups (F=0.11 to1.06, X^2=0.13 to 0.16, P&gt;0.05). CONCLUSION: Antisense TβR Ⅰ and TβR Ⅱ recombinant plasmids have certain reverse effects on liver fibrosis and can be used as possible candidates for gene therapy.     

Effects of gentiana scabra bage on expression of hepatic type Ⅰ,Ⅲ collagen proteins in Paragonimus skrjabini rats with liver fibrosis

Objective:To exploit- the effects of gentiana scabra bage on the expression of hepatic collagen proteins in Paragonimus skrjabini rats with liver fibrosis.Methods:Immunohistochemical technique was used to observe the changes of content of hepatic type Ⅰ,Ⅲ collagen proteins in Paragonimus skrjabini rats with Liver fibrosis before and after the gentiana scabra bage treatmeat.Results:Comparing with the model group,changes of hepatic tvpe Ⅰ and type Ⅲ collagen proteins in gentiana scabra bage treated group were significantly weakened.Conclusions:Gentiana scabra bage treatment can reduce the content of hepatic type Ⅲ and type Ⅰ collagen protein significantly in Paragonimus skrjabini rats with liver fibrosis,thereby,playing the role against hepatic fibrosis.     

Expression of platelet-derived growth factor-BB in liver tissues of patients with chronic hepatitis B

AIM:To study the relationship between expression of platelet-derived growth factor-BB (PDGF-BB) and fibrogenesis inchronic hepatitis B.METHODS:Hepatic tissues from 43 patients with chronichepatitis B were embedded in paraffin.The sections werestained with HE and picric acid-sirius red to determineinflammatory activity and fibrosis stages.PDGF-BB expressionwas detected by immunohistochemistry and assessedsemiquantatively.Levels of serum hyaluronic acid (HA),pro-collagen Ⅲ(PCⅢ),collagen Ⅳ(Ⅳ-C) and laminin (LN)were examined by radioimmunoassay (RIA).RESULTS:The expression level of PDGF-BB was found tobe positively correlated with inflammatory activity,fbrosisstage and grade of histological findings (τ=0.58,0.55,0.55,P<0.01).The positive correlation was also observedbetween tissue level of PDGF-BB expression and contentsof HA,PC≡Ⅲ,Ⅳ-C and LN in the circulation (r=-0.52,0.32,0.40,0.33,P<0.05).CONCLUSION:PDGF-BB may play some role in thedevelopment and progression of liver fibrosis.     

Gardenia jasminoides attenuates hepatocellular injury and fibrosis in bile duct-ligated rats and human hepatic stellate cells

AIM:To investigate the anti-hepatofibrotic effects of Gardenia jasminoides in liver fibrosis.METHODS:Male Sprague-Dawley rats underwent common bile duct ligation(BDL) for 14 d and were treated with Gardenia jasminoides by gavage.The ef-fects of Gardenia jasminoides on liver fibrosis and the detailed molecular mechanisms were also assessed in human hepatic stellate cells(LX-2) in vitro.RESULTS:Treatment with Gardenia jasminoides decreased serum alanine aminotransferase(BDL vs BDL + 100 mg/kg Gardenia jasminoides,146.6 ± 15 U/L vs 77 ± 6.5 U/L,P = 0.0007) and aspartate aminotransferase(BDL vs BDL + 100 mg/kg Gardenia jasminoides,188 ± 35.2 U/L vs 128 ± 19 U/L,P = 0.005) as well as hydroxyproline(BDL vs BDL + 100 mg/kg Gardenia jasminoides,438 ± 40.2 μg/g vs 228 ± 10.3 μg/g liver tissue,P = 0.004) after BDL.Furthermore,Gardenia jasminoides significantly reduced liver mRNA and/or protein expression of transforming growth factor β1(TGF-β1),collagen type?Ⅰ?(Col?Ⅰ) and α-smooth muscle actin(α-SMA).Gardenia jasminoides significantly suppressed the upregulation of TGF-β1,Col?Ⅰand α-SMA in LX-2 exposed to recombinant TGF-β1.Moreover,Gardenia jasminoides inhibited TGF-β1-induced Smad2 phosphorylation in LX-2 cells.CONCLUSION:Gardenia jasminoides exerts antifibrotic effects in the liver fibrosis and may represent a novel antifibrotic agent.     

Bone morphogenetic protein-7 represses hepatic stellate cell activation and liver fibrosis via regulation of TGF-β/Smad signaling pathway

BACKGROUND Liver fibrosis is a refractory disease whose persistence can eventually induce cirrhosis or even liver cancer.Early liver fibrosis is reversible by intervention.As a member of the transforming growth factor-beta(TGF-β)superfamily,bone morphogenetic protein 7(BMP7)has anti-liver fibrosis functions.However,little is known about BMP7 expression changes and its potential regulatory mechanism as well as the relationship between BMP7 and TGF-βduring liver fibrosis.In addition,the mechanism underlying the anti-liver fibrosis function of BMP7 needs to be further explored.AIM To investigate changes in the dynamic expression of BMP7 during liver fibrosis,interactions between BMP7 and TGF-β1,and possible mechanisms underlying the anti-liver fibrosis function of BMP7.METHODS Changes in BMP7 expression during liver fibrosis and the interaction between BMP7 and TGF-β1 in mice were observed.Exogenous BMP7 was used to treat mouse primary hepatic stellate cells(HSCs)to observe its effect on activation,migration,and proliferation of HSCs and explore the possible mechanism underlying the anti-liver fibrosis function of BMP7.Mice with liver fibrosis received exogenous BMP7 intervention to observe improvement of liver fibrosis by using Masson’s trichrome staining and detecting the expression of the HSC activation indicator alpha-smooth muscle actin(α-SMA)and the collagen formation associated protein type I collagen(Col I).Changes in the dynamic expression of BMP7 during liver fibrosis in the human body were further observed.RESULTS In the process of liver fibrosis induced by carbon tetrachloride(CCl4)in mice,BMP7 protein expression first increased,followed by a decrease;there was a similar trend in the human body.This process was accompanied by a sustained increase in TGF-β1 protein expression.In vitro experiment results showed that TGF-β1 inhibited BMP7 expression in a time-and dose-dependent manner.In contrast,high doses of exogenous BMP7 inhibited TGF-β1-induced activation,migration,and proliferation of HSCs;this inhibitory effect was associated with upregulation of pSmad1/5/8 and downregulation of phosphorylation of Smad3 and p38 by BMP7.In vivo experiment results showed that exogenous BMP7 improved liver fibrosis in mice.CONCLUSION During liver fibrosis,BMP7 protein expression first increases and then decreases.This changing trend is associated with inhibition of BMP7 expression by sustained upregulation of TGF-β1 in a time-and dose-dependent manner.Exogenous BMP7 could selectively regulate TGF-β/Smad pathway-associated factors to inhibit activation,migration,and proliferation of HSCs and exert antiliver fibrosis functions.Exogenous BMP7 has the potential to be used as an antiliver fibrosis drug.