Tetrandrine inhibits activation of rat hepatic stellate cells in vitro via transforming growth factor-β signaling

AIM: To investigate the effect of various concentrations of tetrandrine on activation of quiescent rat hepatic stellate cells (HSCs) and transforming growth factor-β(TGF-β) signaling in vitro. METHODS: HSCs were isolated from rats by in situ perfusion of liver and 18% Nycodenz gradient centrifugation, and primarily cultured on uncoated plastic plates for 24 h with DMEM containing 20% fetal bovine serum (FBS/ DMEM) before the culture medium was substituted with 2% FBS/DMEM for another 24 h. Then, the HSCs were cultured in 2% FBS/DMEM with tetrandrine (0.25, 0.5, 1, 2 mg/L, respectively). Cell morphological features were observed under an inverted microscope, smooth muscle-α-actin (α-SMA) was detected by immunocytochemistry and image analysis system, laminin (LN) and type Ⅲ procollagen (PCⅢ) in supernatants were determined by radioimmunoassay. TGF-β1 mRNA, Smad 7 mRNA and Smad 7 protein were analyzed with RT-PCR and Western blotting, respectively. RESULTS: Tetrandrine at the concentrations of 0.25-2 mg/L prevented morphological transformation of HSC from the quiescent state to the activated one, while α-SMA, LN and PCⅢ expressions were inhibited. As estimated by gray values, the expression of α-SMA in tetrandrine groups (0.25, 0.5, 1, 2 mg/L) was reduced from 21.3% to 42.2% (control: 0.67, tetrandrine groups: 0.82, 0.85, 0.96, or 0.96, respectively, which were statistically different from the control, P<0.01), and the difference was more significant in tetrandrine at 1 and 2 mg/L. The content of LN in supernatants was significantly decreased in tetrandrine groups to 58.5%, 69.1%, 65.8% or 60.0% that of the control respectively, and that of PCⅢ to 84.6%, 81.5%, 75.7% or 80.7% respectively (P<0.05 vs control), with no significant difference among tetrandrine groups. RT-PCR showed that TGF-β1 mRNA expression was reduced by tetrandrine treatments from 56.56% to 87.90% in comparison with the control, while Smad 7 mRNA was increased 1.4-4.8 times. The TGF-β1 mRNA and Smad 7 mRNA expression was in a significant negative correlation (r= -0.755, P<0.01), and both were significantly correlated with α-SMA protein expression (r= -0.938, P<0.01; r = 0.938,P<0.01, respectively). The up-regulation of Smad 7 protein by tetrandrine (1 mg/L) was confirmed by Western blotting as well. CONCLUSION: Tetrandrine has a direct inhibiting effect on the activation of rat HSCs in culture. It up-regulates the expression of Smad 7 which in turn blocks TGF-β1 expression and signaling.     

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.     

Expression of transforming growth factor-alpha and hepatitis B surface antigen in human hepatocellular carcinoma tissues and its significance

AIM:To evaluate the expression of transforming growthfactor-alpha (TGF-α) and hepatitis B surface antigen (HBsAg) in human hepatocellular carcinoma (HCC) tissues and its significance.METHODS:Seventy specimens of HCC tissues were detected by immunohistochemical method. Five specimens of normal human liver tissues were used as control.RESULTS: The TGF-o~ positive expression rates in HCC and its surrounding tissues were 74.3%(52/70) and 88.1%(52/59), respectively. TGF-α positive granules were mainly in the cytoplasm and fewer existed on the karyotheca. The TGF-α positive expressing rate in well differentiated HCC was significantly higher than that in moderately and poorly differentiated HCC (P&lt;0.05).The TGF-α positive expression also was observed in intrahepatic bile ducts (part of those were hyperplastic ducts).The HBsAg positive expression rates in HCC and its surrounding tissues were 21.4%(15/70) and 79.7%(47/59), respectively.HBsAg positive granules were in the cytoplasm, inclusion and on the karyotheca.There was a prominent positive correlation between TGF-α and HBsAg expression in HCC surrounding tissues (P&lt;0.05,γ=0.34). TGF-α was usually existed with HBsAg in regenerated and/or dysplastic liver cells.In the five normal liver tissues, TGF-α and HBsAg were not detectable in hepatocytes and bile ducts.CONCLUSION:Hepatitis B virus infection is dosely related with hepatocarcinogenesis.The overexpression of TGF-α in the liver seems to be associated with the regeneration of hepatocytes injured by HBsAg.The continued expression of TGF-α might lead to dysplasia of liver cells and development of HCC. Furthermore, TGF-α might play a role in morphogenesis and regeneration of intrahepatic bile ducts.     

Therapeutic effects and molecular mechanisms of anti-fibrosis herbs and selenium on rats with hepatic fibrosis

AIM:To study the therapeutic effects of anti-fibrosis herbs and selenium on hepatic fibrosis induced by carbon tetrachloride (CCl4) in rats and the underlining molecular mechanisms.METHODS:Fifty-three Wistar rats were randomly divided into:normal control group, model control group, colchicine group, anti-fibrosis herbs group (AF group) and anti-fibrosis herbs plus selenium group (AS group).The last four groups were administered with CCl4 at the beginning of experiment to induce hepatic fibrosis. Then colchicine, anti-fibrosis herbs and selenium were used to treat them. The normal control group and the model control group were given normal saline at the same time. At the end of the 6^th week, rats in each group were sacrificed. Blood and tissue specimens were taken. Serum indicators (ALT, AST, HA, LN) were determined and histopathological changes were graded. Lymphocyte CD4 and CD8 were examined by flow cytometry. Expression of TGF-β1 and NF-κB was detected by immunohistochemistry and expression of TGF-β1 mRNA was detected by semiquantified RT-PCR.RESULTS: Histological grading showed much a smaller degree of hepatic fibrogenesis in AS group and AF group than that in colchicine group and model control group.The serum content of ALT, AST, HA and LN in AF group and AS group were significantly lower than that in colchicine group (ALT:65.8&#177;26.5, 67.3&#177;18.4 and 96.2&#177;20.9 in AF, AS and colchicine groups respectively; AST: 150.8&#177;34.0, 154.6&#177;27.3 and 215.8&#177;24.6 respectively; HA: 228&#177;83, 216&#177;58 and 416&#177;135 respectively; LN:85.9&#177;15.0, 80.6&#177;18.6 and 106.3&#177;14.2 respectively) (P&lt;0.05). The level of CD4 and CD4/CD8 ratio in AF group and AS group was significantly higher that those in cochicine group (CD4:50.8&#177;3.8, 52.6&#177;3.4 and 40.2&#177;2.1 in AF, AS and colchicine groups respectively;CD4/CD8 ratio:1.45,1.46 and 1.26, respectively (P&lt;0.05).The expression level of NF-κB and TGF-β1 in the liver tissues of AF and AS treatment groups was markedly decreased compared with that in cochicine group, and TGF-β1 mRNA was also markedly decreased (1.07&#177;0.31 and 0.98&#177;0.14 vs2.34&#177;0.43, P&lt;0.05).CONCLUSION: Anti-fibrosis herbs and selenium have beneficial effects on hepatic fibrosis in rats by enhancing immunity and inhibiting NF-κB and TGF-β1 expressions.     

Relationship between the expression of iNOS,VEGF,tumor angiogenesis and gastric cancer

AIM：To in vestigate the relationship between the expression of inducible nitric oxide synthase(iNOS),vascular endothelial growth factor(VEGF),the microvascular density(MVD)and the pathological features and clinical staging of gastric cancer.METHODS:Immunohistochemical staining was used for detecting the expression of iNOS and VEGFin46resected specimens of gastric carcinoma;the monoclonal antibody against CD34 was used for displaying vascular endothelial cells,and MVD was detected by counting of CD34-positive vascular endothelial cells.RESULTS:Of 46resected specimens of gastric carcinoma,the rates of expressions of iNOS and VEGF were 58.70%and76.09%,respectively,and MVDaveraged55.59&#177;19.39,Judged by the standard TNM criteria,the rate of expression of iNOS in stageⅣ（84.46%)was higher than those in stageⅠ,Ⅱ,Ⅲ（Fish exact probabilities test,P=0.019,0.023and 0.033,respectively);the rates of expression of VEGFin stage Ⅲ,Ⅳ（76.0%,92.31%,respectively)were higher than those in stageⅠ,Ⅱ（Fis exact probabilities test,P=0.031,0.017,0.022and0.019).MVDs in stageⅢ,Ⅳ（64.72&#177;14.96,67.09&#177;18.29,respectively)were higher than those in stageⅠ,Ⅱ(t\2.378,4.015,2.503and2.450,P&lt;0.05,P&lt;0.001,P&lt;0.001,P&lt;0.05,respectively),In37gastric carcinoma specimens with lymph node metastasis,MVD(68.69&#177;18.07)and the rates of expression of iNOS and VEGF(70.27%,83.78%,respectively)were higher than those in the specimens with absence of metastasis(t=2.205,X^2=6.3587,X^2=6.2584,P&lt;0.01,P&lt;0.05,P&lt;0.05,respectively),MVD and the expressions of iNOS and EGF were not correlated to the location,size or grade of tumor,nor with the depth of invasion of tumor;MVDs in the positive iNOS and VEGF specimens(59.88&#177;18.02,58.39&#177;17.73,repectively)were higher than those in the negative iNOS and VEGF specimens(X^2=6.3587and 6.1574,P&lt;0.05,P&lt;0.05,respectively);thus the expressions of iNOS and VEGF was correlated to MVD,but the expression of iNOS was not correlated to that of VEGF,In addition.of the 46 surviving patients,the 5-year survival rate of patients with positive iNOS or VEGF tumors was significantly less than that of patients with negative iNOS-or VEGF tumors(X^2=4.3842and 5.4073,P&lt;0.05,P&lt;0.05.respectively).CONCLUSION:The expressions of iNOS and VEGF are colosely related to tumor angiogenesis,and are involved in the advancement and the lymph node metastasis;thusMVD and the expressions of iNOS and EGF may serve indexes for evaluating staging of gastric carcinoma and forecasting its risk of metastasis,which will help establish a comprehensive therapeutical measure of post-operative patients and provide a new approach to tumor therapy.     

Tetrandrine inhibits activation of rat hepatic stellate cells in vitro via transforming growth factor-β signaling

AIM: To investigate the effect of various concentrations of tetrandrine on activation of quiescent rat hepatic stellate cells (HSCs) and transforming growth factor-β (TGF-β) signaling in vitro.METHODS: HSCs were isolated from rats by in situperfusion of liver and 18% Nycodenz gradient centrifugation, and primarily cultured on uncoated plastic plates for 24 hwith DMEM containing 20% fetal bovine serum (FBS/DMEM) before the culture medium was substituted with 2% FBS/DMEM for another 24 h. Then, the HSCs were cultured in 2% FBS/DMEM with tetrandrine (0.25, 0.5, 1,2 mg/L, respectively). Cell morphological features were observed under an inverted microscope, smooth muscleα-actin (α-SMA) was detected by immunocytochemistry and image analysis system, laminin (LN) and type Ⅲprocollagen (PCⅢ) in supernatants were determined byradioimmunoassay. TGF-β1 mRNA, Smad 7 mRNA and Smad 7 protein were analyzed with RT-PCR and Western blotting, respectively.RESULTS: Tetrandrine at the concentrations of 0.25-2 mg/L prevented morphological transformation of HSC from the quiescent state to the activated one, while α-SMA, LN and PCⅢ expressions were inhibited. As estimated by gray values, the expression of α-SMA in tetrandrine groups (0.25, 0.5, 1, 2 mg/L) was reduced from 21.3% to 42.2%(control: 0.67, tetrandrine groups: 0.82, 0.85, 0.96, or 0.96, respectively, which were statistically different from the control, P＜0.01), and the difference was more significant in tetrandrine at 1 and 2 mg/L. The content of LN in supernatants was significantly decreased in tetrandrine groups to 58.5%, 69.1%, 65.8% or 60.0% that of the control respectively, and that of PCⅢ to 84.6%, 81.5%,75.7% or 80.7% respectively (P＜0.05 vs control), with no significant difference among tetrandrine groups. RTPCR showed that TGF-β1 mRNA expression was reduced by tetrandrine treatments from 56.56% to 87.90% in comparison with the control, while Smad 7 mRNA was increased 1.4-4.8 times. The TGF-β1 mRNA and Smad 7 mRNA expression was in a significant negative correlation (r= -0.755, P＜0.01), and both were significantly correlated with α-SMA protein expression (r = -0.938, P＜0.01;r = 0.938, P＜0.01, respectively). The up-regulation of Smad 7 protein by tetrandrine (1 mg/L)was confirmed by Western blotting as well.CONCLUSION: Tetrandrine has a direct inhibiting effect on the activation of rat HSCs in culture. It up-regulates the expression of Smad 7 which in turn blocks TGF-β1 expression and signaling.     

Id1 is a critical mediator in TGF-beta-induced transdifferentiation of rat hepatic stellate cells

Transforming growth factor (TGF)-beta is critically involved in the activation of hepatic stellate cells (HSCs) that occurs during the process of liver damage, for example, by alcohol, hepatotoxic viruses, or aflatoxins. Overexpression of the TGF-beta antagonist Smad7 inhibits transdifferentiation and arrests HSCs in a quiescent stage. Additionally, bile duct ligation (BDL)-induced fibrosis is ameliorated by introducing adenoviruses expressing Smad7 with down-regulated collagen and alpha-smooth muscle actin (alpha-SMA) expression. The aim of this study was to further characterize the molecular details of TGF-beta pathways that control the transdifferentiation process. In an attempt to elucidate TGF-beta target genes responsible for fibrogenesis, an analysis of Smad7-dependent mRNA expression profiles in HSCs was performed, resulting in the identification of the inhibitor of differentiation 1 (Id1) gene. Ectopic Smad7 expression in HSCs strongly reduced Id1 mRNA and protein expression. Conversely, Id1 overexpression in HSCs enhanced cell activation and circumvented Smad7-dependent inhibition of transdifferentiation. Moreover, knock-down of Id1 in HSCs interfered with alpha-SMA fiber formation, indicating a pivotal role of Id1 for fibrogenesis. Treatment of HSCs with TGF-beta1 led to increased Id1 protein expression, which was not directly mediated by the ALK5/Smad2/3, but the ALK1/Smad1 pathway. In vivo, Id1 expression and Smad1 phosphorylation were co-induced during fibrogenesis. In conclusion, Id1 is identified as TGF-beta/ALK1/Smad1 target gene in HSCs and represents a critical mediator of transdifferentiation that might be involved in hepatic fibrogenesis. Supplementary material for this article can be found on the HEPATOLOGY website (http://interscience.wiley.com/jpages/0270-9139/suppmat/index.html).     

The role of Smad3 in mediating mouse hepatic stellate cell activation.

Transforming growth factor beta (TGF-beta) is the most potent profibrogenic mediator in liver fibrosis. Although Smad proteins have been identified as intracellular mediators in the TGF-beta signaling pathway, the function of individual Smad proteins remains poorly understood. The aim of this study was to explore the contribution of Smad3 in mediating TGF-beta responses in a model of acute liver injury in vivo and in culture-activated hepatic stellate cells (HSCs). Wild-type, Smad3 heterozygous or Smad3 homozygous knockout mice were treated with a single intragastric administration of CCl(4). After 72 hours, the induction of hepatic collagen alpha1(I) and alpha2(I) messenger RNA (mRNA) levels in Smad3 knockout mice was only 42% and 64%, respectively, of the levels induced in wild-type mice. However, smooth muscle alpha-actin (alpha-SMA) was expressed at a slightly higher level in livers from knockout mice compared with wild-type mice. In culture-activated HSCs from Smad3 knockout mice, collagen alpha1(I) mRNA was 73% of wild-type HSCs, but alpha-SMA expression was the same. HSCs from knockout mice showed a higher proliferation rate than wild-type HSCs. Smad3-deficient HSCs did not form TGF-beta1-induced Smad-containing DNA-binding complexes. In conclusion, (1) maximal expression of collagen type I in activated HSCs requires Smad3 in vivo and in culture; (2) Smad3 is not necessary for HSC activation as assessed by alpha-SMA expression; (3) Smad3 is necessary for inhibition of proliferation of HSCs, which might be TGF-beta-dependent; and (4) Smad3 is required for TGF-beta1-mediated Smad-containing DNA-binding complex formation in cultured HSCs.     

Smad7 prevents activation of hepatic stellate cells and liver fibrosis in rats

BACKGROUND & AIMS: Numerous studies implicate transforming growth factor (TGF)-beta signaling in liver fibrogenesis. To perturb the TGF-beta pathway during this process, we overexpressed Smad7, an intracellular antagonist of TGF-beta signaling, in vivo and in primary-cultured hepatic stellate cells (HSCs). METHODS: Ligation of the common bile duct (BDL) was used to induce liver fibrosis in rats. Animals received injections of an adenovirus carrying Smad7 cDNA into the portal vein during surgery and via the tail vein at later stages. The effect of Smad7 on TGF-beta signaling and activation of HSC was further analyzed in primary-cultured cells. RESULTS: Smad7-overexpressing BDL rats displayed reduced collagen and alpha-SMA expression and reduced hydroxyproline content in the liver, when compared with animals administered AdLacZ. Such a beneficial effect was also observed when Smad7 was expressed in animals with established fibrosis. Accordingly, Smad7 arrested transdifferentiation of primary-cultured HSCs. AdSmad7 infected cells remained in a quiescent stage and retained storage of vitamin A droplets. Smad7 expression totally blocked TGF-beta signal transduction, shown by inhibiting Smad2/3 phosphorylation, nuclear translocation of activated Smad complexes, and activation of (CAGA)(9)-MLP-Luc, resulting in decreased collagen I expression. Smad7 also abrogated TGF-beta-dependent proliferation inhibition of HSC. Smad7 did not decrease expression of alpha-SMA, but immunofluorescent staining with anti alpha-SMA antibodies displayed destruction of the fibrillar organization of the actin cytoskeleton. CONCLUSIONS: In summary, gene transfer of Smad7 inhibits experimental fibrogenesis in vivo. Studies with isolated HSC suggest that the underlying mechanisms involve inhibition of TGF-beta signaling and HSC transdifferentiation.     

粉防己碱对肝星状细胞转化生长因子-β1反应性影响

目的观察低浓度粉防己碱（Tetrandrine）对转化牛长因子-β1（TGF-β1）促进静止期大鼠肝星状细胞（HSCs）活化和维持HSCs活化作用的影响，并探讨该作用与TGF-β1受体后信号通路的关系。方法HSCs原代培养，取静止期（培养3d）和活化HSCs（培养8d），给予TGF-β1（质量浓度5ug／L）和（或）粉防己碱（1．6umol／L）干预，观察HSCs形态变化，分别以RT．PCR和Western blot法检测TGF-β1、Smad7以及α—SMAmRNA和（或）蛋白表达。结果粉防己碱（1．6umol／L）能抑制静止期HSCs胞体伸展，粉防己碱使活化的HSCs膜状伸展的胞体收缩和梭形变，在单纯粉防己碱处理组和混合处理组均可见此现象。在静止期和活化HSCs中，粉防己碱均能抑制TGF-β1．诱导的HSCsd—SMA表达，TGF-β1表达下降，使静止期HSCsSmad7表达上调，但不影响活化HSCs Smad7表达.结论低浓度粉防己碱显著抑制TGF-β1对静止期的HSCs促活化作用和对活化HSCs的活化维持作用，诱导培养活化的HSCs活化逆转，其作用机制在不同活化状态的HSCs中存在差异。     

Arg-gly-asp-mannose-6-phosphate inhibits activation and proliferation of hepatic stellate cells in vitro

AIM: To investigate the effect of arg-gly-asp-mannose-6 phosphate (RGD-M6P) on the activation and proliferation of primary hepatic stellate cells in vitro. METHODS: Hepatic stellate cells (HSCs) were isolated from rats by in situ collagenase perfusion of liver and 18% Nycodenz gradient centrifugation and cultured on uncoated plastic plates for 24 h with DMEM containing 10% fetal bovine serum (FBS/DMEM) before the culture medium was substituted with 2% FBS/DMEM for another 24 h. Then, HSCs were cultured in 2% FBS/DMEM with transforming growth factor beta1, M6P, RGD, or RGD-M6P, respectively. Cell morphology was observed under inverted microscope, smooth muscle alpha-actin (alpha-SMA) was detected by immunocytochemistry, type III procollagen (PC III) in supernatant was determined by radioimmunoassay, and the proliferation rate of HSCs was assessed by flow cytometry. RESULTS: RGD-M6P significantly inhibited the morphological transformation and the alpha-SMA and PC III expressions of HSCs in vitro and also dramatically prevented the proliferation of HSCs in vitro. Such effects were remarkably different from those of RGD or M6P. CONCLUSION: The new compound, RGD-M6P, which has a dramatic effect on primary cultured HSCs in vitro, can inhibit the transformation of HSCs in culture caused by TGFbeta1, suppresses the expression of PC III and decreases proliferation rate of HSC. RGD-M6P can be applied as a selective drug carrier targeting at HSCs, which may be a new approach to the prevention and treatment of liver fibrosis.     

The nuclear receptor SHP mediates inhibition of hepatic stellate cells by FXR and protects against liver fibrosis

BACKGROUND AND AIMS: The farnesoid X receptor (FXR) is an endogenous sensor for bile acids and inhibits bile acid synthesis by inducing small heterodimer partner (SHP) gene expression. The aim of this study was to investigate whether FXR is expressed by and modulates function of hepatic stellate cells (HSCs). METHODS: The antifibrotic activity of FXR ligand was tested in 2 rodent models: the porcine serum and bile duct ligation (BDL). RESULTS: Twelve-week administration of 1-10 mg/kg 6-ethyl chenodeoxycholic acid (6-ECDCA), a synthetic FXR ligand, to porcine serum-treated rats prevented liver fibrosis development and reduced liver expression of alpha1(I) collagen, TGF-beta1 and alpha-SMA mRNA by approximately 90%. Therapeutic administration of 6-ECDCA, 3 mg/kg, to BDL rats reduced liver fibrosis and alpha1(I) collagen, transforming growth factor (TGF)-beta1, alpha-SMA, and tissue metalloproteinase inhibitor (TIMP)-1 and 2 messenger RNA (mRNA) by 70%-80%. No protection was observed in BDL rats treated with CDCA, 3 mg/kg, and ursodeoxycholic acid, 15 mg/kg. FXR expression was detected in HSCs. Exposure of HSCs to FXR ligands caused a 3-fold increase of SHP, reduced alpha1(I)collagen and TGF-beta1 by approximately 60%-70% and abrogates alpha1(I) collagen mRNA up-regulation induced by thrombin and TGF-beta1. By retrovirus infection and small interference RNA, we generated SHP overexpressing and SHP-deficient HSC-T6. Using these cell lines, we demonstrated that SHP binds JunD and inhibits DNA binding of adaptor protein (AP)-1 induced by thrombin. CONCLUSIONS: By demonstrating that an FXR-SHP regulatory cascade promotes resolution of liver fibrosis, this study establish that FXR ligands might represent a novel therapeutic option to treat liver fibrosis.     

奥曲肽抗肝纤维化的实验研究

目的 观察奥曲肽(Oct)对大鼠实验性肝纤维化的治疗效果,并探讨其作用机制。方法 用四氯化碳诱导大鼠肝纤维化模型,将实验动物随机分为正常对照组、治疗前模型组、治疗后模型组和Oct治疗组。Oct治疗组给予Oct(50ng/100g)皮下注射,每日2次,连续用药30d,分别用放射免疫法检测血清层黏连蛋白(LN)、Ⅲ型前胶原(PC Ⅲ)及透明质酸(HA)。VG染色法组织切片观察组织病理变化,免疫组织化学法检测肝组织平滑肌肌动蛋白(α-SMA)和转化生长因子β_1(TGFβ_1)表达及逆转录聚合酶链反应法检测Ⅰ型和Ⅲ型前胶原mRNA表达。结果 治疗前和治疗后模型组大鼠血清HA(ng/L)为121.8±9.5和110.3±13.4,正常对照组为33.1±3.7、LN(μg/L)为85.7±12.1和78.2±7.9,正常对照组为37.1±6.3、PC Ⅲ(ng/L)为35.9±3.5和33.7±2.6,正常对照组为15.6±2.8。Oct组大鼠血清HA为55.8±7.2、LN为43.1±3.4、PC Ⅲ为27.8±3.4,与模型组大鼠比较,差异有显著性,t=2.76～11.07,P<0.05。Oct能显著降低纤维化大鼠肝组织纤维化积分,下调α—SMA和TGFβ_1蛋白质及I型和III前胶原mRNA表达水平。结论 Oct抑制肝星状细胞激活和转化、下调TGFβ_1蛋白质及I型和III型前胶mRNA表达而发挥抗肝纤维化作用。     

Tetrandrine stimulates the apoptosis of hepatic stellate cells and ameliorates development of fibrosis in a thioacetamide rat model

AIM To investigate the therapeutic effect of tetrandrine on liver fibrosis induced by thioacetamide in rats in vivo and in vitro.METHODS In vitro study we investigated the effect of tetrandrine on the apoptosis of rat hepatic stellate cells transformed by simian virus 40 (T-HSC/Cl-6), which retains the features of activated cells. In vivo studyhepatic fibrosis was induced in rats by thioacetamide.Tetrandrine was given orally to rats at doses of 5, 10 or 20 mg/kg for 4 wk compared with intraperitoneal injection of interferon-r.RESULTS In vitro study 5, 10 or 25 μg/mL of tetrandrine-induced activation of caspase-3 in t-HSC/Cl-6 cells occurred dose-depenclently. In vivo study tetrandrine treatment as well as interferon-r significantly ameliorated the development of fibrosis as determined by lowered serum levels of aspartate aminotransferase (AST),alanine aminotransferase (ALT), total bilirubin (T-Bil)and the levels of liver hydroxyproline (Hyp), hyaluronic acid (HA), laminin (LN) and also improved histological findings. The effects of tetrandrine at the concentration of 20 mg/kg were better than the other concentration groups.CONCLUSION Tetrandrine promotes the apoptosis of activated HSCs in vitro. Tetrandrine administration can prevent liver fibrosis and liver damage induced by thioacetamide in rats in vivo, indicating that it might exert a direct effect on rat HSCs.     

Effect of ligand of peroxisome proliferator-activated receptor γ on the biological characters of hepatic stellate cells

AIM: To study the effect of rosiglitazone, which is a ligand of peroxisome proliferator-activated receptor gamma (PPARgamma), on the expression of PPARgamma in hepatic stellate cells (HSCs) and on the biological characteristics of HSCs. METHODS: The activated HSCs were divided into three groups: control group, 3 micromol/L rosiglitazone group, and 10 micromol/L rosiglitazone group. The expression of PPARgamma, alpha-smooth muscle actin (alpha-SMA), and type I and III collagen was detected by RT-PCR, Western blot and immunocytochemical staining, respectively. Cell proliferation was determined with methylthiazolyltetrazolium (MTT) colorimetric assay. Cell apoptosis was demonstrated with flow cytometry. RESULTS: The expression of PPARgamma at mRNA and protein level markedly increased in HSCs of 10 micromol/L rosiglitazone group (t value was 10.870 and 4.627 respectively, P<0.01 in both). The proliferation of HSCs in 10 micromol/L rosiglitazone group decreased significantly (t = 5.542, P<0.01), alpha-SMA expression level and type I collagen synthesis ability were also reduced vs controls (t value = 10.256 and 14.627 respectively, P<0.01 in both). The apoptotic rate of HSCs significantly increased in 10 micromol/L rosiglitazone group vs control (chi(2) = 16.682, P<0.01). CONCLUSION: By increasing expression of PPARgamma in activated HSCs, rosiglitazone, an agonist of PPARgamma, decreases alpha-SMA expression and type I collagen synthesis, inhibits cell proliferation, and induces cell apoptosis.