Rosiglitazone enhances fluorouracil-induced apoptosis of HT-29 cells by activating peroxisome proliferator-activated receptor γ

AIM:To examine whether and how rosiglitazone enhances apoptosis induced by fluorouracil in human colon cancer(HT-29)cells.METHODS:Human colon cancer HT-29 cells were cultured in vitro and treated with fluorouracil and/or rosiglitazone.Proliferation and growth of HT-29 cells were evaluated by MTT assay and trypan blue exclusion methods,respectively.The apoptosis of HT-29 cells was determined by acridine orange/ethidium bromide staining and flow cytometry using PI fluorescence staining.The expressions of peroxisome proliferator-activated receptor γ(PPARγ),Bcl-2 and Bax in HT-29 cells were analyzed by Western blot.RESULTS:Although rosiglitazone at the concentration below 30 μmol/L for 72 h exerted almost no inhibitory effect on proliferation and growth of HT-29 cells,it could significantly enhance fluorouracil-induced HT-29 cell proliferation and growth inhibition.Furthermore,10 μmol/L rosilitazone did not induce apoptosis of HT-29 cells but dramatically enhanced fluorouracil-induced apoptosis of HT-29 cells.However,rosiglitazone did not improve apoptosis induced by fluorouracil in HT-29 cells pretreated with GW9662,a PPARγ antagonist.Meanwhile,the expression of Bax and PPARγ was up-regulated,while the expression of Bcl-2 was down regulated in HT-29 cells treated with rosiglitazone in a time-dependent manner.However,the effect of rosiglitazone on Bcl-2 and Bax was blocked or diminished in the presence of GW9662.CONCLUSION:Rosiglitazone enhances fluorouracil-induced apoptosis of HT-29 cells by activating PPARγ.     

Effect of caffeic acid phenethyl ester on proliferation and apoptosis of hepatic stellate cells in vitro

AIM: To investigate the role of nuclear factor-κB (NF-κB)inhibitor caffeic acid phenethy1 ester (CAPE) in the proliferation, collagen synthesis and apoptosis of hepatic stellate cells (HSCs) of rats. METHODS: The HSCs from rats were isolated and cultured in Dulbecco's Modified Eagle's Medium (DMEM) and treated with CAPE. The proliferation and collagen synthesis of HSCs were determined by 3H-TdR and 3H-proline incorporation respectively, and the expression of type Ⅰ, Ⅲ procollagen genes was further explored byin situ hybridization. Apoptosis cell indices (AIs) were examined using terminal deoxynucleotidyl transferase- mediated DIG-dUTP nick end labeling (TUNEL). RESULTS: Tn activated HSC in culture, CAPE significantly inhibited 3H-TdR and 3H-proline incorporation by HSCs at concentrations of 5 μmol/L and 10 μmol/L respectively. CAPE also reduced the type I procollagen gene expression (P＜0.05)at higher concentration. Apoptosis of HSC was induced by CAPE and the AIs were time-and dose-dependently increased from 2.82+0.73 % to 7.66±1.25 % at 12 h (P＜0.01) and from 3.15±0.88 % to 10.6L±2.88 % at 24 h (P＜0.01). CONCLUSION: CAPE inhibits proliferation and collagen synthesis of HSC at lower concentration and induces HSC apoptosis at higher concentration.     

Involvement of 90-kuD ribosomal S6 kinase in collagen type Ⅰ expression in rat hepatic fibrosis

AIM: To investigate the relationship between 90-kuD ribosomal S6 kinase (p90RSK) and collagen type Ⅰ expression during the development of hepatic fibrosis in vivo and in vitro. METHODS: Rat hepatic fibrosis was induced by intraperitoneal injection of dimethylnitrosamine. The protein expression and cell location of p90RSK and their relationship with collagen type Ⅰ were determined by co-immunofluoresence and confocal microscopy. Subsequently, RNAi strategy was employed to silence p90RSK mRNA expression in HSC-T6, an activated hepatic stellate cell (HSC) line. The expression of collagen type Ⅰ in HSC-T6 cells was assessed by Western blotting and real-time polymerase chain reaction. Furthermore, HSCs were transfected with expression vectors or RNAi constructs of p90RSK to increase or decrease the p90RSK expression, then collagen type Ⅰ promoter activity in the transfected HSCs was examined by reporter assay. Lastly HSC-T6 cells transfected with p90RSK siRNA was treated with or without platelet-derived growth factor (PDGF)-BB at a final concentration of 20 μg/L and the cell growth was determined by MTS conversion. RESULTS: In fibrotic liver tissues, p90RSK was overexpressed in activated HSCs and had a significant positive correlation with collagen type Ⅰ levels. In HSC-T6 cells transfected with RNAi targeted to p90RSK, the expression of collagen type Ⅰ was downregulated (61.8% in mRNA, P < 0.01, 89.1% in protein, P < 0.01). However, collagen type Ⅰ promoter activity was not increased with over-expression of p90RSK and not decreased with low expression either, compared with controls in the same cell line ( P = 0.076). Furthermore, p90RSK siRNA exerted the inhibition of HSC proliferation, and also abolished the effect of PDGF on the HSC proliferation. CONCLUSION: p90RSK is over-expressed in activated HSCs and involved in regulating the abnormal expression of collagen type Ⅰ through initiating the proliferation of HSCs.     

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.     

Effects of interleukin-10 on activation and apoptosis of hepatic stellate cells in fibrotic rat liver

AIM:To study the effects of interleukin-10(IL-10)on the expression of α-smooth muscle actin(α-SMA),nuclear factor-κB(NF-κB)and Fas/Fas ligand(FasL)inhepatic stellate cells of experimental rats with hepaticfibrosis.METHODS:Sixty clean SD rats were randomly dividedinto control group(group N),liver fibrotic group(groupC)and IL-10 treatment group(group I).Control groupreceived intraperitoneal injection of saline(2ml·kg~(-1)),twicea week.Fibrotic group was injected intraperitoneallywith 50% carbon tetrachloride(CCl_4)(2 ml·kg~(-1)),twicea week.IL-10 treatment group was given IL-10 at adose of 4 μg·kg~(-1)20 minutes before CCl_4 administrationfrom the third week.Hepatic stellate cells(HSCs)wereisolated from these rats at the seventh and eleventhweeks during the course of liver fibrosis,respectively.The expression of α-SMA and NF-κB in HSCs wasmeasured by S-P immunohistochemistry.The expressionof Fas and FasL mRNA was measured by RT-PCR.Furthermore,liver tissues were harvested from threegroups at the same time.RESULTS:The CCl_4- induced experimental rat hepaticfibrosis model was established successfully.The purityof extracted hepatic stellate cells was about 95% andthe yield of hepatic stellate cells was 1.2-2.3×10~6/g livertissue averagely.The positive expression of α-SMA andNF-κB was 36.5% and 28.5% respectively in group N.The positive levels of α-SMA and NF-κB were increasedsignificantly in group C compared to group N(P<0.01).The positive signals decreased significantly(P<0.05)ingroup I.In the 11~(th)week,the HSCs of group I becameround with visible pyknotic nuclei.The expression ofNF-μB in group C was significantly increased in a time-dependentmanner(P<0.01),but there was no difference in the α-SMA expression(P>0.05).The mRNA of Fasand FasL in group C was significantly increased in a time-dependent manner compared to that in control group.After treated with IL-10,the expression level of Fas andFasL was higher in group I than in group C.CONCLUSION:The positive expression of α-SMA andNF-κB in hepatic stellate cells is decreased by ectogenicIL-10 in liver fibrosis induced by CCl_4.The expression ofFas and FasL is increased in the course of liver fibrosis,and is further increased by IL-10.IL-10 could inhibitthe activation of HSCs and cause apoptosis of activatedHSCs.     

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.     

Suppressive effects of 171β-estradiol on hepatic fibrosis in CCI4-induced rat model

AIM: To investigate the pathway via which 17β-estradio(β-Est) exerts suppressive effects on rat hepatic fibrosis.METHODS: In vivo study was done in CCI4-induced female hepatofibrotic rats. Fibrosis-suppressive effect of β-Est(20 μg/kg&#183;d) was evaluated in intact and ovariectomized rat models. Six weeks after the treatment, all the rats were sacrificed and specimens of serum or liver tissue were collected for the studies. Serum liver enzymes,fibrosis markers and estradiol levels were determined by standard enzymatic methods, ELISA and RIA, respectively.Degrees of fibrosis and areas of hepatic stellate cells(HSCs) positive for alpha-smooth muscle actin (a-SMA) in the liver were determined by van Gieson (VG) stain and immunohistochemistry. In vitro studies, HSCs were isolated by a combination of pronase-collagenase perfusion and density gradient centrifugation. First-passage HSCs were randomly divided into 10 groups, and different concentrations of β-Est, 2-hydroxyestradiol (2OHE) or 2-methoxyestradiol(2MeOE) were separately added to the cell groups. After incubation for 72 h, the degree of cell proliferation, collagen production, ~-SMA or estrogen receptor (ER) expression was determined by MTT assay, ELISA and immunohistochemistry,respectively.RESULTS: β-Est treatment reduced aspartate aminotransfer-ase (AST), alanine aminotransferase (ALT), hyaluronic acid(HA) and type IV collagen (C IV) in sera, suppressed hepatic collagen content, decreased the areas of HSCs positive for α-SMA significantly in both intact and ovariectomized female hepatofibrotic rats. There was a negative correlation between the percentage of fibrotic area of liver tissue and the serum estradiol level; the calculated correlation coefficient was -0.57 (P&lt;0.01). β-Est and its metabolites concentration-dependently (10^-9 mol/L-10^-7 mol/L) inhibited HSC proliferation and collagen synthesis. At the concentration of 10^-7 mol/L, they could inhibit α-SMA expression. The order of potency was 2MeOE&gt;2OHE&gt;β-Est.CONCLUSION: β-Est may suppress hepatic fibrosis probably via its biologically active metabolites.     

Rosiglitazone prevents murine hepatic fibrosis induced by Schistosoma japonicum

AIM： To evaluate the effect of rosiglitazone in a murine model of liver fibrosis induced by Schistosoma japonicum infection. METHODS： A total of 50 mice were randomly and averagely divided into groups A, B, C, D and E. The mice in group A served as normal controls, while those in the other four groups were infected with Schistosoma japonicum to induce the model of liver fibrosis. Besides, the mice in groups C, D and E were treated with praziquantel, rosiglitazone and praziquantel plus rosiglitazone, respectively. NF-κB binding activity and expression of PPARγ-mRNA were determined by Western blot assay and real-time quantitative PCR. Radioimmunonassay technique was used to detect the serum content changes of TNF-α and IL-6. Histological specimens were stained with HE. Expression of TGF-β1, a-smooth muscle actin and type Ⅰand type Ⅲ collagen was detected by immunohistochemistry and multimedia color pathographic analysis system.
RESULTS： Inflammation and fibrosis in the rosiglitazone plus praziquantel treatment group （group E） were lightest among the mice infected with Schistosoma （P 〈 0.05）. To further explore the mechanism of rosiglitazone action, we found that rosiglitazone can significantly increase the expression of PPARγ [E： -18.212 ± （-3.909） vs B： -27.315 ± （-6.348） and C： -25.647 ± （-5.694）, P 〈 0.05],reduce the NF-κB binding activity （E： 88.89 ± 19.34 vs B： 141.11 ± 15.37, C： 112.89 ± 20.17 and D： 108.89 ± 20.47, P 〈 0.05）, and lower the serum level of TNF-α （E： 1.613 ± 0.420 ng/mL vs B： 2.892 ± 0.587 ng/mL, C： 2.346 ± 0.371 ng/mL and D： 2.160 ± 0.395 ng/mL, P 〈 0.05） and IL-6 （E： 0.106 ± 0.021 ng/mL vs B： 0.140 ± 0.031 ng/mL and C： 0.137 ± 0.027 ng/mL, P 〈 0.05） in mice with liver fibrosis. Rosiglitazone can also substantially reduce the hepatic expression of TGF-β1, α-SMA type Ⅰand type Ⅲ collagen in mice with liver fibrosis. CONCLUSION： The activation of PPARγ by its ligand can retard liver fi     

Antioxidant axis Nrf2-keap1-ARE in inhibition of alcoholic liver fibrosis by IL-22

AIM To explore the effect of interleukin(IL)-22 on in vitro model of alcoholic liver fibrosis hepatic stellate cells(HSCs), and whether this is related to regulation of Nrf2-keap1-ARE.METHODS HSC-T6 cells were incubated with 25, 50, 100, 200 and 400 μmol/L acetaldehyde. After 24 and 48 h, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay was used to detect proliferation of HSCs to choose the best concentration and action time. We used the optimal concentration of acetaldehyde(200 μmol/L) to stimulate HSCs for 24 h, and treated the cells with a final concentration of 10, 20 or 50 ng/m L IL-22. The cell proliferation rate was detected by MTT assay. The cell cycle was analyzed by flow cytometry. The expression of nuclear factor-related factor(Nrf)2 and α-smooth muscle antigen was detected by western blotting and immunocytochemistry. The levels of malondialdehyde(MDA) and glutathione(GSH) were measured by spectrophotometry. RESULTS In the MTT assay, when HSCs were incubated with acetaldehyde, activity and proliferation were higher than in the control group, and were most obvious after 48 h treatment with 200 μmol/L acetaldehyde. The number of cells in G0/G1 phases was decreased and the number in S phase was increased in comparison with the control group. When treated with different concentrations of IL-22, HSC-T6 cell activity and proliferation rate were markedly decreased in a dosedependent manner, and cell cycle progression was arrested from G1 to S phase. Western blotting and immunocytochemistry demonstrated that expression of Nrf2 total protein was not significantly affected. Expression of Nrf2 nuclear protein was low in thecontrol group, increased slightly in the model group(or acetaldehyde-stimulated group), and increased more obviously in the IL-22 intervention groups. The levels of MDA and GSH in the model group were significantly enhanced in comparison with those in the control group. In cells treated with IL-22, the MDA level was attenuated but the GSH level was further increased. These changes were dose-dependent. CONCLUSION IL-22 inhibits acetaldehyde-induced HSC activation and proliferation, which may be related to nuclear translocation of Nrf2 and increased activity of the antioxidant axis Nrf2-keap1-ARE.     

Adeno-associated virus mediated interferon-gamma inhibits the progression of hepatic fibrosis in vitro and in vivo

AIM: To investigate the effects of adeno-associated virus (AAV) mediated expression of human interferon-γ for gene therapy in experimental hepatic fibrosis in vitro and in vivo. METHODS: We constructed the recombinant AAV encoding human INF-γ (rAAV- INF-γ) and took the primary rat hepatic stellate cells and carbon tetrachloride induced rats as the experimental hepatic fibrosis model in vitro and in vivo. Immunocytochemistry analysis was used to reveal the expression of α-SMA, the marker protein expressed in hepatic stellate cells. The mRNA expression of TGF-β, TIMP-1, and MMP-13 were analyzed by RT-PCR method. In vivo study, the hydroxyproline content in liver and serum AST, ALT were also detected. RESULTS: In vitro study, AAV vector could mediated efficient expression of human INF-γ, which inhibit the activation of hepatic stellate cells, decrease the expression of α-SMA and mRNA of TIMP-1, TGF-β, with the MMP-13 unchanged. In vivo study, the histological examination revealed that rAAV- INF-γ could inhibit the progression of the hepatic fibrosis. In the rAAV-INF-γ induced group, the hydroxyproline content and serum AST, ALT level were decreased to 177±28 μg/g wet liver, 668.5±140.0, 458.4±123.5 U/L, compare with the fibrosis control group 236±31 μg/g wet liver, 1 019.1±276.3, 770.5±154.3 U/L, respectively (P<0.01). mRNA expression of TIMP-1 in the rAAV-INF-γ induced rat liver was decreased while no significant change was observed in TGF-β and MMP-13. CONCLUSION: All these results indicated that rAAV-INF-γ has potential effects for gene therapy of hepatic fibrosis, which could inhibit the progression of hepatic fibrosis.     

Suppressive effects of 17β-estradiol on hepaUc fibrosis in CCl_4-induced rat model

AIM:To investigate the pathway via which 17β-estradiol(β-Est) exerts suppressive effects on rat hepatic fibrosis.METHODS:In vivo study was done in CCl_4-induced femalehepatofibrotic rats.Fibrosis-suppressive effect of β-Est(20μg/kg·d) was evaluated in intact and ovariectomizedrat models.Six weeks after the treatment,all the ratswere sacrificed and specimens of serum or liver tissuewere collected for the studies.Serum liver enzymes,fibrosis markers and estradiol levels were determined bystandard enzymatic methods,ELISA and RIA,respectively.Degrees of fibrosis and areas of hepatic stellate cells(HSCs) positive for alpha-smooth muscle actin (α-SMA) inthe liver were determined by van Gieson (VG) stain andimmunohistochemistry.In vitro studies,HSCs were isolatedby a combination of pronase-collagenase perfusion anddensity gradient centrifugation.First-passage HSCs wererandomly divided into 10 groups,and different concentrationsof β-Est,2-hydroxyestradiol (2OHE) or 2-methoxyestradiol(2MeOE) were separately added to the cell groups.Afterincubation for 72h,the degree of cell proliferation,collagenproduction,α-SMA or estrogen receptor (ER) expression wasdetermined by MTI- assay,ELISA and immunohistochemistry,respectively.RESULTS:β-Est treatment reduced aspartate aminotransfer-ase (AST),alanine aminotransferase (ALT),hyaluronic acid(HA) and type Ⅳ collagen (C Ⅳ) in sera,suppressed hepaticcollagen content,decreased the areas of HSCs positive forα-SMA significantly in both intact and ovariectomized femalehepatofibrotic rats.There was a negative correlationbetween the percentage of fibrotic area of liver tissue andthe serum estradiol level;the calculated correlationcoefficient was -0.57 (P<0.01).β-Est and its metabolitesconcentration-dependently (10~(-9)mol/L-10~(-7)mol/L) inhibitedHSC proliferation and collagen synthesis.At the concentrationof 10~(-7)mol/L,they could inhibit α-SMA expression.Theorder of potency was 2MeOE>2OHE>β-Est.CONCLUSION:β-Est may suppress hepatic fibrosis probablyvia its biologically active metabolites.     

Efficacy of Chinese medicine Yi-gan-kang granule in prophylaxis and treatment of liver fibrosis in rats

AIM: To investigate the efficacy of a Chinese medicine, Yi-gan-kang granule (granules for benefiting the liver), in prophylaxis and treatment of liver fibrosis in rats and its possible mechanism. METHODS: One hundred and forty Sprague-Dawley rats were randomly divided into seven groups (20 each): group 1, blank control group without any interference during the study; group 2, CCI4-induced liver fibrosis group; group 3, pig serum-induced liver fibrosis group; group 4, prophylaxis group of CCl4-induced liver fibrosis by Yi-gan-kang; group 5, prophylaxis group of pig serum-induced liver fibrosis by Yi-gan-kang; group 6, treatment group of CCI4-induced liver fibrosis by Yi-gan-kang; group 7, treatment group of CCI4-induced liver fibrosis by Yi-gan-kang. At wk 6,10,14 and 20 (baseline for CCl4., or big serum induction), five rats in each group were anesthetized and their livers were removed for pathological studies including immunohistochemical studies for α-SMA, type I collagen and In situ hybridization of tissue inhibitor of metalloproteinase-1 (TTMP-1) mRNA of hepatic stellate cells (HSCs). Anti-lipid peroxidation in isolated mitochondria and 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) colorimetric assay for proliferation and terminal deoxynucleotidyl transferase-medicated dUTP-biotin nick end-labeling (TUNEL), flow cytometry and electron microscopy for apoptosis in isolated HSCs were also studied. RESULTS: The mean number of pseudolobuli at wk 10, 14 and 20 in the prophylaxis group was significantly less than that in the control group (P<0.05 or 0.01). The effect of prophylaxis at wk 14 in CCI4 rats and at wk 10 in pig serum-induced rats was much better than that of treatment group (P<0.01). The thickness (in μm) of fibers both in pig serum-induced prophylaxis and in treatment groups at wk 14 and. 20 was significantly less than that in control group (P<0.05). The number of fibers both in prophylaxis and in treatment groups from wk 10 or 14 to 20 was significantly less than that in control group (P<0.05 or P<0.01). The tissue HSC positive rates of type I collagen, α-SMA and TIMP-1 mRNA, which represented the active phenotype of HSCs in tissues, remained very high from wk 6 to the end of model making in control group. While in prophylaxis group, they were at a relatively low level. In treatment group, there was a gradual decreasing trend. Time- and dose-dependent effects of anti-lipid peroxidation on isolated mitochondria, cell proliferation and apoptosis in cultured HSCs were also observed during the study. CONCLUSION: Yi-gan-kang can effectively inhibit or inverse the course of liver fibrogenesis in CCI4- and pig serum-induced rat models.     

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 oncell proliferation and the expression of c-myb,TGF-131 andα1-I collagen in cultured hepatic stellate cells (HSC) from rats.METHODS:Recombinant retroviral vector of c-myb antisensegene (pDOR-myb) was constructed,and then transfectedinto retroviral package cell line PA317 by means of DOTARThe pseudoviruses produced from the resistant PA317 cellswere selected with G418 to infect HSCs isolated from ratlivers.The cell proliferation was measured by 3-[4,5-Dimethylthiazolzyl]-2,5-diphenyl tetrazo-dium bromide(MIT) method.The expression of c-myb,α_1-I collagen andTGF-β1 mRNA,and c-myb protein in HSCs was detectedwith semi-quantitive reverse transeription-polymerase chainreaction (RT-PCR) and Western-blot respectively.RESULTS:HSCs from rats were isolated successfully withthe viability>98%.In the pDOR-myb infected HSCs,the c-myb protein expression,cell proliferation,and α_1-I collagenand TGF-β1 mRNA expression were repressed significantlycompared with their corresponding control groups (P<0.01).CONCLUSION:c-myb plays a key role in activation andproliferation of HSC.c-myb antisense RNA can inhibit cellproliferation,α_1-I collagen and TGF-β1 mRNA expression,suggesting that inhibition of c-myb gene expression mightbe a potential way for the treatment of liver fibrosis.     

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.     

Peroxisome proliferator activated receptor-y in pathogenesis of experimental fatty liver disease

AIM:To study the expression of peroxisome proliferatoractivated receptor-γ(PPARγ) in the liver of rats with fattyliver disease (FLD) and to explore the role of PPARγ in thepathogenesis of FLD to provide the basis for using PPARγligand to treat patients with FLD.METHODS:Forty Wistar rats were divided into 4 groupsof ten rats each randomly:normal group (group A),alcoholgroup (group B),fat-rich diet group (group C),alcohol andfat-rich diet group (group D).The rats were sacrificed atthe end of the 16th week from the feeding day.Alanineaminotransferase (ALT),tumor necrosis factor-alfa (TNFα)in serum and malondialdehyde (MDA) in liver homogenatewere determined;livers were collected for observingpathologic changes by HE,Sudan Ⅳ,Masson stain undermicroscope.The morphologic results were analyzed bypicture quantitative analysis technique.The changes ofultrastructure were also examined under electron microscope.The expression of PPARγ in liver was detected by immunoh-istochemistry and RT-PCR.The correlations between theexpression of PPARy and biochemical indexes,and liverhistology were analyzed.RESULTS:The steatosis,inflammation,necrosis and fibrosiswere present in livers of different experimental groups,especially in livers of alcohol and fat-rich diet group.Thecontent of immunodetectable PPARγ was decreasedremarkably in the livers of model rats (group B-D);the levelin alcohol and fat-rich diet group (3.43±1.48) was significantlylower than that in normal group (18.34±3.73),alcohol group(8.82±2.52) and fat-rich diet group (11.73±2.51) (all P<0.01).The level of PPARγ mRNA was also lower in the livers ofmodel rats (group B-D) than in livers of controls.Theexpression of PPARγ in rat liver correlated negatively withthe degree of its inflammation,necrosis and fibrosis,aswell as the level of serum TNFα and the content of MDA inliver homogenates,but not with steatosis or serum ALT.CONCLUSION:Decreased expression of PPARγ may playan important role in the development of hepatocellularinflammation,necrosis and fibrosis of rats with FLD.Thus,activating PPARγ by its ligand can be anticipated to providea therapy target for FLD.     

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.     

罗格列酮抑制糖基化终产物诱导心肌成纤维细胞增殖和结缔组织生长因子及Smad的表达

Objective To investigate the effects of rosiglitazone on the proliferation,connective tissue growth factor and Smad expression in cultured cardiac fibroblasts induced by advanced glycosylation end-products (AGEs).Methods After being treated with various amounts of rosiglitazone,the cultured neonatal rat cardiac fibroblasts were incubated with AGEs.The status of cardiac fibroblasts proliferation and cell cycle were detected by 3-(4,5-dimethyhhiazol-2-yl) -2,5-diphenyl tetrazolium bromide (MTI) assay and flow cytometry.Furthermore,ELISA technique was applied to identify the level of TGF-β1.The protein expressions of CTGF and Smad in cardiac fibroblasts of neonatal SD rats were detected with Western blotting.Results The exposure of cardiac fibroblasts to AGEs at doses of 0-200 mg/L induced a dose-dependent increase in cell proliferation.At the concentration of rosiglitazooe (0.1,1,and 10 μmol/L),the cell proliferation was reduced compared with 200 mg/L AGEs group by O.823±0.072,0.785±0.060,0.601±0.081 vs 0.981±0.049,respectively (P < 0.05).The increased levels of TGF-β1 in supematants of cultured cardiac fibroblasts stimulated by AGEs were inhibited by rosiglitazone at the concentrations of 0.1,1,10μmol/L by 257.77±9.09,230.29±6.56,200.84±10.26 vs 300.68±8.56,respectively (vs 200 mg/L AGEs,P<0.01).Western blot indicated that pretreatment with rosiglitazone (0.1,1,and 10 μmol/L) inhibited CTGF protein production in a dose-dependent by 0.769±0.108,0.590±0.095,0.534±0.115 vs 1.021±0.113,respectively (vs 200 mg/L AGEs,P<0.01).It was also demonstrated that pretreatment with rosiglitazone (1 and 10 μmol/L) inhibited Smad2 protein production by 0.424±0.059,0.396±O.080 vs 0.572±0.073,respectively (vs 200 mg/L AGEs,P < 0.05 or P < 0.01).Meanwhile pretreatment with rosiglitazone (1 and 10 μmol/L) inhibited Smad4 protein production by 0.580±0.063,0.556±0.051 vs 0.672±0.059,respectively (vs 200 mg/L AGEs,P < 0.05 or P < 0.01).Conclusions The findings suggest that AGEs promote the proliferation of cardiac fibroblasts and stimulate the protein production of Smad and CTGF of cardiac fibroblasts.Rosiglitazone inhibits the above reaction.These results indicate that CTGF/Smad pathway may play an important role in the protective effect of rosiglitazone on myocardial fibrosis.     

罗格列酮抑制糖基化终产物诱导心肌成纤维细胞增殖和结缔组织生长因子及Smad的表达

Objective To investigate the effects of rosiglitazone on the proliferation,connective tissue growth factor and Smad expression in cultured cardiac fibroblasts induced by advanced glycosylation end-products (AGEs).Methods After being treated with various amounts of rosiglitazone,the cultured neonatal rat cardiac fibroblasts were incubated with AGEs.The status of cardiac fibroblasts proliferation and cell cycle were detected by 3-(4,5-dimethyhhiazol-2-yl) -2,5-diphenyl tetrazolium bromide (MTI) assay and flow cytometry.Furthermore,ELISA technique was applied to identify the level of TGF-β1.The protein expressions of CTGF and Smad in cardiac fibroblasts of neonatal SD rats were detected with Western blotting.Results The exposure of cardiac fibroblasts to AGEs at doses of 0-200 mg/L induced a dose-dependent increase in cell proliferation.At the concentration of rosiglitazooe (0.1,1,and 10 μmol/L),the cell proliferation was reduced compared with 200 mg/L AGEs group by O.823±0.072,0.785±0.060,0.601±0.081 vs 0.981±0.049,respectively (P < 0.05).The increased levels of TGF-β1 in supematants of cultured cardiac fibroblasts stimulated by AGEs were inhibited by rosiglitazone at the concentrations of 0.1,1,10μmol/L by 257.77±9.09,230.29±6.56,200.84±10.26 vs 300.68±8.56,respectively (vs 200 mg/L AGEs,P<0.01).Western blot indicated that pretreatment with rosiglitazone (0.1,1,and 10 μmol/L) inhibited CTGF protein production in a dose-dependent by 0.769±0.108,0.590±0.095,0.534±0.115 vs 1.021±0.113,respectively (vs 200 mg/L AGEs,P<0.01).It was also demonstrated that pretreatment with rosiglitazone (1 and 10 μmol/L) inhibited Smad2 protein production by 0.424±0.059,0.396±O.080 vs 0.572±0.073,respectively (vs 200 mg/L AGEs,P < 0.05 or P < 0.01).Meanwhile pretreatment with rosiglitazone (1 and 10 μmol/L) inhibited Smad4 protein production by 0.580±0.063,0.556±0.051 vs 0.672±0.059,respectively (vs 200 mg/L AGEs,P < 0.05 or P < 0.01).Conclusions The findings suggest that AGEs promote the proliferation of cardiac fibroblasts and stimulate the protein production of Smad and CTGF of cardiac fibroblasts.Rosiglitazone inhibits the above reaction.These results indicate that CTGF/Smad pathway may play an important role in the protective effect of rosiglitazone on myocardial fibrosis.