Alterations of mast cells and TGF-β1 on the silymarin treatment for CCl_4-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 CCI4-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 CCU-treated group, increase of hepatic stellate cells and TGF-β1 production were lower than in the CCI4-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 CCI4+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.     

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.     

CT perfusion at early stage of hepatic diffuse disease

AIM: To determine the validity of the non-invasive method of CT perfusion (CTP) in rat model of hepatic diffuse disease. METHODS: Twenty-eight Wistar rats were divided into two groups. Liver diffuse lesions were induced by diethyln-itrosamine in 14 rats of test group. Rats in control group were bred with pure water. From the 1st to 12th wk after the test group was intervened, both groups were studied every week with CTP. CTP parameters of liver parenchyma in different periods and pathologic changes in two groups were compared and analyzed. RESULTS: The process of hepatic diffuse lesions in test groups was classified into three stages or periods according to the pathologic alterations, namely hepatitis, hepatic fibrosis, and cirrhosis. During this period, hepatic artery flow (HAF) of control group declined slightly, mean transit time (MTT), blood flow (BF) and volume (BV) increased, but there were no significant differences between different periods. In test group, HAF tended to increase gradually, MTT prolonged obviously, BV and BF decreased at the same time. The results of statistical analysis revealed that the difference in the HAF ratio of test group to control group was significant. The ratio of BV and BF in test group to control group in stage of hepatitis and hepatic cirrhosis, hepatic fibrosis and early stage of hepatic cirrhosis was significantly different, but there was no significant difference between hepatitis and hepatic fibrosis. The main pathological changes in stage of hepatitis were swelling of hepatic cells, while sinusoid capillarization and deposition of collagen aggravated gradually in the extravascular Disse's spaces in stage of fibrosis and early stage of cirrhosis. CONCLUSION: The technique could reflect some early changes of hepatic blood perfusion in rat with liver diffuse disease and is valuable for their early diagnosis.     

Effect of IL-10 on the expression of HSC growth factors in hepatic fibrosis rat

AIM: To study the effect of IL-10 on the expression of growth factors - transforming growth factor-β1(TGF-β1), epidermal growth factor (EGF), hepatocyte growth factor (HGF)and platelet-derived growth factor (PDGF) of hepatic stellate cells (HSCs) of hepatic fibrosis rat and the anti-fibrogenic role of exogenous IL-10. METHODS: Hepatic fibrosis was induced by CCl4 administration intra-peritoneally. Sixty clean male Sprague-Dawley (SD) rats were randomly divided into three groups: normal control group (GN, 8 rats), hepatic fibrosis model group (GC, 28 rats) and IL-10 treated group (GI, 24 rats). At the beginning of the 7th and 11th wk, rats in each group were routinely perfused with pronase E and type IV collag-enase through a portal vein catheter and the suspension obtained from the liver was spun by centrifugation with 11% Nycodenz density gradient to isolate HSCs. Histological examination was used to determine the degree of hepatic fibrosis. RT-PCR was employed to analyze mRNA expression from freshly isolated cells. Immunocytochemistry was performed to detect protein expression in primary cultured HSCs. RESULTS: Rat hepatic fibrosis was developed with the increase of injection frequency of CCl4, and HSCs were successfully isolated. At the 7th and 11th wk, TGF-β1, EGF, and HGF mRNA in GC increased obviously compared with GN (P= 0.001/0.042, 0.001/0.001, 0.001/0.001) and GI (P=0.001/0.007, 0.002/0.001, 0.001/0.001). For TGF-β1, no difference was observed between GI and GN. For EGF, mRNA level in GI increased compared with GN during the 7th wk (P=0.005) and 11th wk (P=0.049). For HGF, mRNA level in GI decreased compared with GN at the 7th wk (P=0.001) and 11th wk (P=0.021). Between these two time points, TGF-β1 expression at the 7th wk was higher than that of the 11th wk (P=0.049), but for EGF, the former was lower than the latter (P=0.022). As for PDGF mRNA, there was no significant difference between these groups, but difference seemed to exist in protein levels. Results by immunocytochemistry of TGF-β1 and EGF were paralleled with the above findings. CONCLUSION: The expression of TGF-β1, EGF and HGF increased in HSC of hepatic fibrosis rat and decreased after treatment with IL-10. IL-10 plays an anti-fibrogenic role by suppressing growth factors expression.     

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 herbsand selenium on hepatic fibrosis induced by carbontetrachloride (CCl_4) in rats and the underlining molecularmechanisms.METHODS:Fifty-three Wistar rats were randomly dividedinto:normal control group,model control group,colchicinegroup,anti-fibrosis herbs group (AF group) and anti-fibrosisherbs plus selenium group (AS group).The last four groupswere administered with CCl_4 at the beginning of experimentto induce hepatic fibrosis.Then colchicine,anti-fibrosis herbsand selenium were used to treat them.The normal controlgroup and the model control group were given normal salineat the same time.At the end of the 6~(th) week,rats in eachgroup were sacrificed.Blood and tissue specimens weretaken.Serum indicators (ALT,AST,HA,LN) were determinedand histopathological changes were graded.Lymphocyte CD_4and CD_8 were examined by flow cytometry.Expression ofTGF-β_1 and NF-κB was detected by immunohistochemistryand expression of TGF-β_1 mRNA was detected by semi-quantified RT-PCR.RESULTS:Histological grading showed much a smallerdegree of hepatic fibrogenesis in AS group and AF groupthan that in colchicine group and model control group.Theserum content of ALT,AST,HA and LN in AF group and ASgroup were significantly lower than that in colchicine group(ALT:65.8±26.5,67.3±18.4 and 96.2±20.9 in AF,AS andcolchicine groups respectively;AST:150.8±34.0,154.6±27.3and 215.8±24.6 respectively;HA:228±83,216±58 and416±135 respectively;LN:85.9±15.0,80.6±18.6 and106.3±14.2 respectively) (P<0.05).The level of CD_4 andCD_4/CD_8 ratio in AF group and AS group was significantly higherthat those in cochicine group (CD_4:50.8±3.8,52.6±3.4 and40.2±2.1 in AF,AS and colchicine groups respectively;CD_4/CD_8 ratio:1.45,1.46 and 1.26,respectively (P<0.05).The expression level of NF-κB and TGF-β_1 in the liver tissuesof AF and AS treatment groups was markedly decreasedcompared with that in cochicine group,and TGF-β_1 mRNAwas also markedly decreased (1.07±0.31 and 0.98±0.14 vs2.34±0.43,P<0.05).CONCLUSION:Anti-fibrosis herbs and selenium havebeneficial effects on hepatic fibrosis in rats by enhancingimmunity and inhibiting NF-κB and TGF-β_1 expressions.     

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.     

Hepatoprotective effect of Cichorium intybus L.,a traditional Uighur medicine,against carbon tetrachloride-induced hepatic fibrosis in rats

AIM:To investigate the hepatoprotective effect of a Cichorium intybus L.extract(CIE)on CCl4-induced hepatic fibrosis in rats.METHODS:Seventy-two male Wistar albino rats were randomly divided into six groups of twelve rats each.The normal control group was allowed free access to food and water.Liver injury was performed in the remaining five groups with an i.p.injection of a 1.0mL/kg CCl4 and olive oil(2:3 v/v)mixture,twice weekly for 8 weeks.All rats,with the exception of the injury model group,were intragastrically(i.g.,)administered quantum satis(q.s.)dosages[CIE group:6,18,and 54 mg/kg,respectively;Fu Fang Bie Jia Ruan Gan Pian(FFBJRGP)group:780 mg/kg].The oral administration of different drugs was performed on the day before CCl4 administration and subsequently once per day for8 wk.The serum levels of aspartate aminotransferase(AST),alanine aminotransferase(ALT),hexadecenoic acid(HA),laminin(LN),hydroxyproline(Hyp),and glutathione(GSH),malondialdehyde(MDA)and superoxide dismutase(SOD)in the rat livers were measured.Histopathological changes in the liver were assessed for each group using HE staining and a Masson Trichrome examination.The expression of transforming growth factor-β1(TGF-β1)andα-smooth muscle actin(α-SMA)was examined by immunohistochemical analysis.RESULTS:CIE at oral doses of 6,18,and 54 g/kg per day showed a significant hepatoprotective effect,especially at a dose of 54 g/kg per day.CIE doses reduced the levels of AST(149.04±34.44,P<0.01),ALT(100.72±27.19,P<0.01),HA(548.50±65.09,P<0.01),LN(28.69±3.32,P<0.01)and Hyp(263.33±75.82,P<0.01).With regards to hepatoprotective activity,the CIE dose of 54 g/kg per day produced the largest significant effect by increasing GSH(3.11±0.81),SOD(269.98±33.77,P<0.01)and reducing MDA(2.76±0.51,P<0.01)levels in the liver.The expressions of TGF-β1 andα-SMA were measured by immunohistology and found to be significantly reduced by CIE in a dose-dependent manner.     

The effect of oxygen on the development of atherosclerosis in WHHL rabbits

The effect of hyperoxic or hypoxic inhalation on blood lipid levels and on the development of atherosclerosis was studied in young male WHHL rabbits. They were exposed to ordinary room air containing different concentrations of oxygen: 6 animals were exposed to 40% oxygen (hyperoxia group) or 5-10% oxygen (hypoxia group) for 5 h a day, 5 days a week for 8 weeks. Four control rabbits inhaled ordinary room air. The following results were obtained. (1) The severity of aortic lesions significantly decreased in the hyperoxia group and increased in the hypoxia group, when these two groups were compared. However, both hypoxic and hyperoxic groups did not statistically differ from the control. (2) Plasma cholesterol levels were not changed either by hyperoxic or hypoxic inhalation. (3) Plasma triglyceride levels were elevated only in the hypoxia group, with significant differences from the values in both control and hyperoxia groups. (4) There was no significant correlation between mean plasma lipid level and severity of aortic lesions. From these results, we conclude that hyperoxic or hypoxic inhalation respectively regresses or aggravates the development of atherosclerotic lesions, not by an indirect action on blood lipid concentrations but by a direct action on the vascular wall.     

Transforming growth factor-β and toll-like receptor-4 polymorphisms are not associated with fibrosis in haemochromatosis

AIM:To investigate the role of genetic polymorphisms in the progression of hepatic fibrosis in hereditary haemochromatosis.METHODS:A cohort of 245 well-characterised C282Y homozygous patients with haemochromatosis was studied,with all subjects having liver biopsy data and DNA available for testing.This study assessed the association of eight single nucleotide polymorphisms(SNPs)in a total of six genes including toll-like receptor 4(TLR4),transforming growth factor-beta(TGF-β),oxoguanine DNA glycosylase,monocyte chemoattractant protein 1,chemokine C-C motif receptor 2 and interleukin-10 with liver disease severity.Genotyping was performed using high resolution melt analysis and sequencing.The results were analysed in relation to the stage of hepatic fibrosis in multivariate analysis incorporating other cofactors including alcohol consumption and hepatic iron concentration.RESULTS:There were significant associations between the cofactors of male gender(P=0.0001),increasing age(P=0.006),alcohol consumption(P=0.0001),steatosis(P=0.03),hepatic iron concentration(P<0.0001)and the presence of hepatic fibrosis.Of the candidate gene polymorphisms studied,none showed a significant association with hepatic fibrosis in univariate or multivariate analysis incorporating cofactors.We also specifically studied patients with hepatic iron loading above threshold levels for cirrhosis and compared the genetic polymorphisms between those with no fibrosis vs cirrhosis however there was no significant effect from any of the candidate genes studied.Importantly,in this large,well characterised cohort of patients there was no association between SNPs for TGF-βor TLR4and the presence of fibrosis,cirrhosis or increasing fibrosis stage in multivariate analysis.CONCLUSION:In our large,well characterised group of haemochromatosis subjects we did not demonstrate any relationship between candidate gene polymorphisms and hepatic fibrosis or cirrhosis.     

Role of TGF-β1/Smads pathway in carotid artery remodeling in renovascular hypertensive rats and prevention by Enalapril and Amlodipine

Objective To investigate the role of transforming growth factor-β1 (TGF-β1), Smad2/3 and Smad7 expressions in carotid artery remodeling in renovascular hypertensive rats, and also the therapeutic effect of Enalapril and Amlodipine. Methods The renovascular hypertensive rat (RHR) models with “two-kidney and one-clip” were established, including model group (n = 6), sham-operated group (n = 6), Enalapril group (10 mg/kg per day, n = 6), Amlodipine group (5 mg/kg per day, n = 6) and combination group (Amlodipine 2.5 mg/kg per day + Enalapril 5mg/kg per day, n = 6). The medication were continuous administrated for six weeks. Carotid artery morphological and structural changes in the media were observed by HE staining, Masson staining and immuno histochemical staining. Media thickness (MT), MT and lumen diameter ratio (MT/LD), and the expression levels of media α-smooth muscle actin (α-actin), proliferating cell nuclear antigen (PCNA), TGF-β1, phosphorylated Smad2/3 (p-Smad2/3) and Smad7 in carotid arteries were measured. Results The media of carotid arteries in RHR model group was significantly thickened, the volume of smooth muscle cell was increased, and the array was in disorder; MT, MT/LD, the proliferation index of smooth muscle cell and collagen fiber area percentage of carotid arteries in the model group were significantly higher than those in the sham-operated group (P < 0.01). Compared to sham-operated group, the model group had significantly higher expressions of TGF-β1 and p-Smad2/3 (P < 0.05) and lower Smad7 expression. Both Enalapril and Amlodipine improved smooth muscle hypertrophy and collagen deposition, reduced RHR carotid MT, MT/LD, proliferation index of smooth muscle cell, collagen fiber area percentage and the expressions of TGF-β1 and p-Smad2/3 (P < 0.05), increased Smad7 expression (P < 0.05). Moreover, the combination treatment of Enalapril and Amlodipine had significantly better effects than single Amlodipine group (P < 0.05), but not single Enalapril group. Conclusions TGF-β1/Smads pathway may participate in the mechanism of carotid artery remodeling in RHR; the role of Amlodipine and Enalapril in inversing carotid artery remodeling may be related to the change of TGF-β1/Smads pathway, the combination treatment of Amlodipine and Enalapril had better effects than single administration of Amlodipine.     

Correlation between anti-fibrotic effect of baicalin and serum cytokines in rat hepatic fibrosis

AIM： To investigate the correlation between the antifibrotic effect of baicalin and serum cytokine production in rat hepatic fibrosis, METHODS： Forty male Sprague-Dawley rats were divided randomly into four groups： normal control group, model group, baicalin-treated group, and colchicine-treated group. Except for the normal control group, all rats in the other groups were administered with carbon tetrachloride to induce hepatic fibrosis. At the same time, the last two groups were also treated with baicalin or colchicine. At the end of the 8 wk, all animals were sacrificed. Serum alanine aminotransferase （ALl＇）, aspartate aminotransferase （AST）, transforming growth factor （TGF）-β1, tumor necrosis factor （TNF）-α, interleukin （IL）-6 and IL-10 were measured. Liver index, hepatic hydroxyproline content and the degree of liver fibrosis were also evaluated. RESULTS： The levels of ALT, AST and liver index in the baicalin-treated group were markedly lower than those in the model group （ALT： 143.88 ± 14.55 U/L vs 193.58± 24.35 U/L; AST： 263.66 ± 44.23 U/L vs 404.37± 68.29 U/L; liver index： 0.033 ± 0.005 vs 0.049± 0.009, P 〈 0.01）. Baicalin therapy also significantly attenuated the degree of hepatic fibrosis, collagen area and collagen area percentage in liver tissue （P 〈 0.01）. Furthermore, the levels of serum TGF-β1, TNF-α and IL-6 were strikingly reduced in the baicalin-treated group compared with the model group, while the production of IL-10 was up-regulated： （TGF-β1：260.21 ± 31.01 pg/mL vs 375.49 ± 57.47 pg/mL; TNF-α： 193.40±15.18 pg/mL vs 260.04 ± 37.70 pg/mL; IL-α：339.87 ± 72.95 pg/mL vs 606.47 ± 130.73 pg/mL; IL-10：506.22 ± 112.07 pg/mL vs 316.95 ± 62.74 pg/mL, P 〈 0.01）. CONCLUSION： Baicalin shows certain therapeutic effects on hepatic fibrosis, probably by immunoregulating the imbalance between profibrotic and antifibrotic cytokines.