A novel model of non-alcoholic steatohepatitis with fibrosis and carcinogenesis in connexin 32 dominant-negative transgenic rats

Non-alcoholic steatohepatitis (NASH) is a recognized risk factor for liver fibrosis and malignancies, and is associated with features of metabolic syndrome, such as obesity and insulin resistance (IR). We previously demonstrated that the disturbance of connexin 32 (Cx32), a gap junctional protein of hepatocytes, exacerbated NASH in Cx32 dominant-negative transgenic (Cx32ΔTg) rats fed methionine choline-deficient diet (MCDD). MCDD is well-established means of inducing NASH in rodents; however, the Cx32ΔTg-MCDD NASH model does not reproduce obesity and IR. In this study, we aimed to establish an improved NASH model. Eight-week-old male Cx32ΔTg and wild-type (Wt) rats received a high-fat diet (HFD) with dimethylnitrosamine (DMN) for 12 weeks. The HFD with DMN led to gains in body, liver, and visceral fat weights in both genotypes. IR was significantly greater in Cx32ΔTg than in Wt rats. Elevation of serum hepatic enzymes (AST, ALT), inflammatory cytokine expressions (Tnfα, Il-6, Tgf-β1, Il-1β, Timp2, and Col1a1), steatohepatitis, and fibrosis were significantly greater in Cx32ΔTg as compared with Wt rats. Regarding carcinogenesis, the number and area of glutathione S-transferase placental form (GST-P)-positive preneoplastic hepatic foci were significantly increased in Cx32ΔTg versus Wt rats. Moreover, activation of NF-κB and JNK contributed to the progression of NASH in Cx32ΔTg rats. These results suggest that Cx32 dysfunction promoted the progression of NASH, metabolic syndrome, and carcinogenesis. Therefore, the novel Cx32ΔTg-HFD-DMN NASH model may be a rapid and useful tool for evaluating the progression of NASH.

Hepatocyte Deletion of Triglyceride-Synthesis Enzyme Acyl CoA: Diacylglycerol Acyltransferase 2 Reduces Steatosis Without Increasing Inflammation or Fibrosis in Mice

Nonalcoholic fatty liver disease (NAFLD) is characterized by excess lipid accumulation in hepatocytes and represents a huge public health problem owing to its propensity to progress to nonalcoholic steatohepatitis, fibrosis, and liver failure. The lipids stored in hepatic steatosis (HS) are primarily triglycerides (TGs) synthesized by two acyl-CoA:diacylglycerol acyltransferase (DGAT) enzymes. Either DGAT1 or DGAT2 catalyzes this reaction, and these enzymes have been suggested to differentially utilize exogenous or endogenously synthesized fatty acids, respectively. DGAT2 has been linked to storage of fatty acids from de novo lipogenesis, a process increased in NAFLD. However, whether DGAT2 is more responsible for lipid accumulation in NAFLD and progression to fibrosis is currently unknown. Also, it is unresolved whether DGAT2 can be safely inhibited as a therapy for NAFLD. Here, we induced NAFLD-like disease in mice by feeding a diet rich in fructose, saturated fat, and cholesterol and found that hepatocyte-specific Dgat2 deficiency reduced expression of de novo lipogenesis genes and lowered liver TGs by ~70%. Importantly, the reduction in steatosis was not accompanied by increased inflammation or fibrosis, and insulin and glucose metabolism were unchanged. Conclusion: This study suggests that hepatic DGAT2 deficiency successfully reduces diet-induced HS and supports development of DGAT2 inhibitors as a therapeutic strategy for treating NAFLD and preventing downstream consequences.

Sub-Chronic Microcystin-LR Liver Toxicity in Preexisting Diet-Induced Nonalcoholic Steatohepatitis in Rats

Microcystin-LR (MCLR) is a hepatotoxic cyanotoxin reported to cause a phenotype similar to nonalcoholic steatohepatitis (NASH). NASH is a common progressive liver disease that advances in severity due to exogenous stressors such as poor diet and toxicant exposure. Our objective was to determine how sub-chronic MCLR toxicity affects preexisting diet-induced NASH. Sprague-Dawley rats were fed one of three diets for 10 weeks: control, methionine and choline deficient (MCD), or high fat/high cholesterol (HFHC). After six weeks of diet, animals received vehicle, 10 µg/kg, or 30 µg/kg MCLR via intraperitoneal injection every other day for the final 4 weeks. Incidence and severity scoring of histopathology endpoints suggested that MCLR toxicity drove NASH to a less fatty and more fibrotic state. In general, expression of genes involved in de novo lipogenesis and fatty acid esterification were altered in favor of decreased steatosis. The higher MCLR dose increased expression of genes involved in fibrosis and inflammation in the control and HFHC groups. These data suggest MCLR toxicity in the context of preexisting NASH may drive the liver to a more severe phenotype that resembles burnt-out NASH.

Perilipin-2 promotes obesity and progressive fatty liver disease in mice through mechanistically distinct hepatocyte and extra-hepatocyte actions

KEY POINTS

Wild-type mice and mice with hepatocyte-specific or whole-body deletions of perilipin-2 (Plin2) were used to define hepatocyte and extra-hepatocyte effects of altered cellular lipid storage on obesity and non-alcoholic fatty liver disease (NAFLD) pathophysiology in a Western-diet (WD) model of these disorders. Extra-hepatocyte actions of Plin2 are responsible for obesity, adipose inflammation and glucose clearance abnormalities in WD-fed mice. Hepatocyte and extra-hepatic actions of Plin2 mediate fatty liver formation in WD-fed mice through distinct mechanisms. Hepatocyte-specific actions of Plin2 are primary mediators of immune cell infiltration and fibrotic injury in livers of obese mice.

ABSTRACT

Non-alcoholic fatty liver disease (NAFLD) is an obesity- and insulin resistance-related metabolic disorder with progressive pathology. Perilipin-2 (Plin2), a ubiquitously expressed cytoplasmic lipid droplet scaffolding protein, is hypothesized to contribute to NAFLD in humans and rodent models through effects on cellular lipid metabolism. In this study, we delineate hepatocyte-specific and extra-hepatocyte Plin2 mechanisms regulating the effects of obesity and insulin resistance on NAFLD pathophysiology in mice fed an obesogenic Western-style diet (WD). Total Plin2 deletion (Plin2-Null) fully protected WD-fed mice from obesity, insulin resistance, adipose inflammation, steatohepatitis (NASH) and liver fibrosis found in WT animals. Hepatocyte-specific Plin2 deletion (Plin2-HepKO) largely protected against NASH and fibrosis and partially protected against steatosis in WD-fed animals, but it did not protect against obesity, insulin resistance, or adipose inflammation. Significantly, total or hepatocyte-specific Plin2 deletion impaired WD-induced monocyte recruitment and pro-inflammatory macrophage polarization found in livers of WT mice. Analyses of the molecular and cellular processes mediating steatosis, inflammation and fibrosis identified differences in total and hepatocyte-specific actions of Plin2 on the mechanisms promoting NAFLD pathophysiology. Our results demonstrate that hepatocyte-specific actions of Plin2 are central to the initiation and pathological progression of NAFLD in obese and insulin-resistant mice through effects on immune cell recruitment and fibrogenesis. Conversely, extra-hepatocyte Plin2 actions promote NAFLD pathophysiology through effects on obesity, inflammation and insulin resistance. Our findings provide new insight into hepatocyte and extra-hepatocyte mechanisms underlying NAFLD development and progression.

The small molecule drug diminazene aceturate inhibits liver injury and biliary fibrosis in mice

There is no established medical therapy to treat biliary fibrosis resulting from chronic inflammation in the biliary tree. We have recently shown that liver-specific over-expression of angiotensin converting enzyme 2 (ACE2) of the renin angiotensin system (RAS) ameliorated liver fibrosis in mice. Diminazene aceturate (DIZE), a small molecule drug approved by the US Food and Drug Administration, which is used to treat human trypanosomiasis, has been shown to have antifibrotic properties by enhancing ACE2 activity. In this study we sought to determine the therapeutic potential of DIZE in biliary fibrosis using bile duct ligated and multiple drug resistant gene-2 knockout mice. Additionally, human hepatic stellate (LX-2) and mouse Kupffer (KUP5) cell lines were used to delineate intracellular pathways. DIZE treatment, both in vivo and in vitro, markedly inhibited the activation of fibroblastic stellate cells which was associated with a reduced activation of Kupffer cells. Moreover, DIZE-inhibited NOX enzyme assembly and ROS generation, activation of profibrotic transcription factors including p38, Erk1/2 and Smad2/3 proteins and proinflammatory and profibrotic cytokine release. These changes led to a major reduction in biliary fibrosis in both models without affecting liver ACE2 activity. We conclude that DIZE has a potential to treat biliary fibrosis.

NLRP3 inflammasome driven liver injury and fibrosis: Roles of IL-17 and TNF in mice

The NLRP3 inflammasome, a caspase-1 activation platform, plays a key role in the modulation of liver inflammation and fibrosis. Here, we tested the hypothesis that interleukin 17 (IL-17) and tumor necrosis factor (TNF) are key cytokines involved in amplifying and perpetuating the liver damage and fibrosis resulting from NLRP3 activation. To address this hypothesis, gain-of-function Nlrp3A350V knock-in mice were bred onto il17a and Tnf knockout backgrounds allowing for constitutive Nlrp3 activation in myeloid derived cells in mice deficient in IL-17 or TNF. Livers of Nlrp3A350V knock-in mice exhibited severe liver inflammatory changes characterized by infiltration with neutrophils, increased expression of chemokine (C-X-C motif) ligand (CXCL) 1 and CXCL2 chemokines, activated inflammatory macrophages, and elevated levels of IL-17 and TNF. Mutants with ablation of il17a signal showed fewer neutrophils when compared to intact Nlrp3A350V mutants, but still significant inflammatory changes when compared to the nonmutant il17a knockout littermates. The severe inflammatory changes associated with mutant Nlrp3 were almost completely rescued by Tnf knockout in association with a marked decrease in circulating IL-1β levels. Intact Nlrp3A350V mutants showed changes in liver fibrosis, as evidenced by morphometric quantitation of Sirius Red staining and increased mRNA levels of profibrotic genes, including connective tissue growth factor and tissue inhibitor of matrix metalloproteinase 1. Il17a lacking mutants exhibited amelioration of the aforementioned fibrosis, whereas Tnf-deficient mutants showed no signs of fibrosis when compared to littermate controls. Conclusion: Our study uncovers key roles for TNF and, to a lesser extent, IL-17 as mediators of liver inflammation and fibrosis induced by constitutive NLRP3 inflammasome activation in myeloid-derived cells. These findings may lead to therapeutic strategies aimed at halting the progression of liver injury and fibrogenesis in various liver pathogeneses driven by NLRP3 activation. (Hepatology 2018;67:736-749).

Ascorbate lacks significant influence in rats with bile duct ligation-induced liver injury

BACKGROUND

Liver inflammation may induce fibrogenesis, cirrhosis and portal hypertension. Liver cirrhosis is characterized by increased intrahepatic resistance and enhanced vasoconstrictive response. The splanchnic vasodilatation, angiogenesis and portosystemic collaterals formation further bring about lethal complications. Ascorbate is a potent antioxidant with anti-inflammation, anti-fibrosis, and anti-angiogenesis effects. However, the relevant influences in chronic liver injury have not been sufficiently explored.

METHODS

Chronic liver injury was induced in Spraque-Dawley rats with common bile duct ligation (BDL). Ascorbate (250 mg/kg/day, oral gavage) or vehicle was administered starting on the 1st day after operation. On the 8th (hepatitis) and 29th (cirrhosis) day, serum biochemistry parameters, hepatic concentrations of lipid peroxidation-related substances, protein expressions of α-SMA, TGF-β, iNOS, eNOS, p-eNOS-Ser1177, p-eNOS-Thr496, VEGF, VEGFR2, p-VEGFR2, and liver histology were evaluated. In three series of paralleled groups, rats treated with 28-day ascorbate or vehicle received hemodynamic measurements, hepatic and collateral vasoresponsiveness perfusion experiments, mesenteric CD31 immunofluorescence staining, and Western blot analyses of mesenteric VEGF, VEGFR2, pVEGFR2, PDGF, PDGFβ, COX1, COX2, eNOS, p-eNOS-Thr495, p-eNOS-Ser1177 protein expressions. In another series, the severity of portosystemic shunting was evaluated.

RESULTS

Ascorbate did not influence hepatitis, oxidative stress, fibrosis, and hemodynamic parameters in BDL rats. The intrahepatic and collateral vasoresponsiveness were not affected, either from direct incubation or acute treatment with ascorbate. Furthermore, the mesenteric angiogenesis and severity of shunting were not influenced.

CONCLUSION

The oxidative stress, fibrosis, hemodynamic derangements, angiogenesis and vascular functional changes in BDL-induced chronic liver injury may be too overwhelming to be modulated by ascorbate.

Thymic NF-κB-inducing kinase regulates CD4+ T cell-elicited liver injury and fibrosis in mice

BACKGROUND & AIMS

The liver is an immunologically-privileged organ. Breakdown of liver immune privilege has been reported in chronic liver disease; however, the role of adaptive immunity in liver injury is poorly defined. Nuclear factor-κB-inducing kinase (NIK) is known to regulate immune tissue development, but its role in maintaining liver homeostasis remains unknown. This study aimed to assess the role of NIK, particularly thymic NIK, in regulating liver adaptive immunity.

METHODS

NIK was deleted systemically or conditionally using the Cre/loxp system. Cluster of differentiation [CD]4+ or CD8+ T cells were depleted using anti-CD4 or anti-CD8 antibody. Donor bone marrows or thymi were transferred into recipient mice. Immune cells were assessed by immunohistochemistry and flow cytometry.

RESULTS

Global, but not liver-specific or hematopoietic lineage cell-specific, deletion of NIK induced fatal liver injury, inflammation, and fibrosis. Likewise, adoptive transfer of NIK-null, but not wild-type, thymi into immune-deficient mice induced liver inflammation, injury, and fibrosis in recipients. Liver inflammation was characterized by a massive expansion of T cells, particularly the CD4+ T cell subpopulation. Depletion of CD4+, but not CD8+, T cells fully protected against liver injury, inflammation, and fibrosis in NIK-null mice. NIK deficiency also resulted in inflammation in the lung, kidney, and pancreas, but to a lesser degree relative to the liver.

CONCLUSIONS

Thymic NIK suppresses development of autoreactive T cells against liver antigens, and NIK deficiency in the thymus results in CD4+ T cell-orchestrated autoimmune hepatitis and liver fibrosis. Thus, thymic NIK is essential for the maintenance of liver immune privilege and liver homeostasis.

LAY SUMMARY

We found that global or thymus-specific ablation of the NIK gene results in fatal autoimmune liver disease in mice. NIK-deficient mice develop liver inflammation, injury, and fibrosis. Our findings indicate that thymic NIK is essential for the maintenance of liver integrity and homeostasis.

Connexin32 deficiency exacerbates carbon tetrachloride-induced hepatocellular injury and liver fibrosis in mice

OBJECTIVE

Liver fibrosis results from the perpetuation of the normal wound healing response to several types of injury. Despite the wealth of knowledge regarding the involvement of intracellular and extracellular signaling pathways in liver fibrogenesis, information about the role of intercellular communication mediated by gap junctions is scarce.

METHODS

In this study, liver fibrosis was chemically induced by carbon tetrachloride in mice lacking connexin32, the major liver gap junction constituent. The manifestation of liver fibrosis was evaluated based on a series of read-outs, including collagen morphometric and mRNA analysis, oxidative stress, apoptotic, proliferative and inflammatory markers.

RESULTS

More pronounced liver damage and enhanced collagen deposition were observed in connexin32 knockout mice compared to wild-type animals in experimentally triggered induced liver fibrosis. No differences between both groups were noticed in apoptotic signaling nor in inflammation markers. However, connexin32 deficient mice displayed decreased catalase activity and increased malondialdehyde levels.

CONCLUSION

These findings could suggest that connexin32-based signaling mediates tissue resistance against liver damage by the modulation of the antioxidant capacity. In turn, this could point to a role for connexin32 signaling as a therapeutic target in the treatment of liver fibrosis.

Microbiome and bacterial translocation in cirrhosis

Qualitative and quantitative changes in gut microbiota play a very important role in cirrhosis. Humans harbour around 100 quintillion gut bacteria, thus representing around 10 times more microbial cells than eukaryotic ones. The gastrointestinal tract is the largest surface area in the body and it is subject to constant exposure to these living microorganisms. The existing symbiosis, proven by the lack of proinflammatory response against commensal bacteria, implies the presence of clearly defined communication lines that contribute to the maintenance of homeostasis of the host. Therefore, alterations of gut flora seem to play a role in the pathogenesis and progress of multiple liver and gastrointestinal diseases. This has made its selective modification into an area of high therapeutic interest. Bacterial translocation is defined as the migration of bacteria or bacterial products from the intestines to the mesenteric lymph nodes. It follows that alteration in gut microbiota have shown importance, at least to some extent, in the pathogenesis of several complications arising from terminal liver disease, such as hepatic encephalopathy, portal hypertension and spontaneous bacterial peritonitis. This review sums up, firstly, how liver disease can alter the common composition of gut microbiota, and secondly, how this alteration contributes to the development of complications in cirrhosis.

Exposure to fine airborne particulate matters induces hepatic fibrosis in murine models

BACKGROUND & AIMS

Hepatic fibrosis, featured by the accumulation of excessive extracellular matrix in liver tissue, is associated with metabolic disease and cancer. Inhalation exposure to airborne particulate matter in fine ranges (PM2.5) correlates with pulmonary dysfunction, cardiovascular disease, and metabolic syndrome. In this study, we investigated the effect and mechanism of PM2.5 exposure on hepatic fibrogenesis.

METHODS

Both inhalation exposure of mice and in vitro exposure of specialized cells to PM2.5 were performed to elucidate the effect of PM2.5 exposure on hepatic fibrosis. Histological examinations, gene expression analyses, and genetic animal models were utilized to determine the effect and mechanism by which PM2.5 exposure promotes hepatic fibrosis.

RESULTS

Inhalation exposure to concentrated ambient PM2.5 induces hepatic fibrosis in mice under the normal chow or high-fat diet. Mice after PM2.5 exposure displayed increased expression of collagens in liver tissues. Exposure to PM2.5 led to activation of the transforming growth factor β-SMAD3 signaling, suppression of peroxisome proliferator-activated receptor γ, and expression of collagens in hepatic stellate cells. NADPH oxidase plays a critical role in PM2.5-induced liver fibrogenesis.

CONCLUSIONS

Exposure to PM2.5 exerts discernible effects on promoting hepatic fibrogenesis. NADPH oxidase mediates the effects of PM2.5 exposure on promoting hepatic fibrosis.

Activation of Slit2-Robo1 signaling promotes liver fibrosis

BACKGROUND & AIMS

The secretory protein Slit2 and its receptor Robo1 are believed to regulate cell growth and migration. Here, we aimed to determine whether Slit2-Robo1 signaling mediates the pathogenesis of liver fibrosis.

METHODS

Serum levels of Slit2 in patients with liver fibrosis were determined by ELISA. Liver fibrosis was induced in wild-type (WT), Slit2 transgenic (Slit2-Tg) and Robo1(+/-)Robo2(+/-) double heterozygotes (Robo1/2(+/-)) mice by carbon tetrachloride (CCl4). The functional contributions of Slit2-Robo1 signaling in liver fibrosis and activation of hepatic stellate cells (HSCs) were investigated using primary mouse HSCs and human HSC cell line LX-2.

RESULTS

Significantly increased serum Slit2 levels and hepatic expression of Slit2 and Robo1 were observed in patients with liver fibrosis. Compared to WT mice, Slit2-Tg mice were much more vulnerable to CCl4-induced liver injury and more readily develop liver fibrosis. Development of hepatic fibrosis in Slit2-Tg mice was associated with a stronger hepatic expression of collagen I and α-smooth muscle actin (α-SMA). However, liver injury and hepatic expression of collagen I and α-SMA were attenuated in CCl4-treated Robo1/2(+/-) mice in response to CCl4 exposure. In vitro, Robo1 neutralizing antibody R5 and Robo1 siRNA downregulated phosphorylation of Smad2, Smad3, PI3K, and AKT in HSCs independent of TGF-β1. R5 and Robo1 siRNA also inhibited the expression of α-SMA by HSCs. Finally, the protective effect of R5 on the CCl4-induced liver injury and fibrosis was further verified in mice.

CONCLUSIONS

Slit2-Robo1 signaling promotes liver injury and fibrosis through activation of HSCs.

Contrast-enhanced ultrasonography for the evaluation of liver fibrosis after biliary obstruction

AIM: To investigate perfusion change in contrast-enhanced ultrasonography (CEUS) to evaluate liver fibrosis based on biliary obstruction using an animal model.

METHODS: New Zealand white rabbits (3-4 kg) underwent bile duct ligation to form a biliary obstruction model. We performed liver CEUS and laboratory tests on the day before the operation (day 0) and every 7 postoperative days until the rabbits were sacrificed. After CEUS, signal intensity of liver parenchyma with a time-intensity curve was analyzed. Perfusion parameters were automatically calculated from region-of-interests, including peak signal intensity, mean transit time, area under the curve and time to peak. Histological grades of liver fibrosis were assessed according to the Metavir score system immediately after sacrifice. Generalized estimating equations were used to analyze the association between liver fibrosis grades and perfusion parameters for statistical analysis. The perfusion parameters were measured on the last day and the difference between day 0 and the last day were evaluated.

RESULTS: From the nine rabbits, histological grades of liver fibrosis were grade 1 in one rabbit, grade 2 and 3 in three rabbits each, and grade 4 in two rabbits. Among the four CEUS parameters, only the peak signal intensity measured on the last day demonstrated a significant association with liver fibrosis grades (OR = 1.392, 95%CI: 1.114-1.741, P = 0.004). The difference in peak signal intensity between day 0 and the last day also demonstrated an association with liver fibrosis (OR = 1.191, 95%CI: 0.999-1.419, P = 0.051). The other parameters tested, including mean transit time, area under the curve, and time to peak, showed no significant correlation with liver fibrosis grades.

CONCLUSION: This animal study demonstrates that CEUS can be used to evaluate liver fibrosis from biliary obstruction using peak signal intensity as a parameter.

Cyclic adenosine monophosphate-responsive element modulator alpha overexpression impairs function of hepatic myeloid-derived suppressor cells and aggravates immune-mediated hepatitis in mice

Molecular factors driving immune-mediated inflammation in the liver are incompletely understood. The transcription factor, cyclic adenosine monophosphate-responsive element modulator alpha (CREMα) can endorse differentiation of T lymphocytes toward T-helper (Th)17 cells, thereby promoting autoimmunity in systemic lupus erythematosus or lung inflammation. To investigate the role of CREMα in liver disease, we subjected transgenic (Tg) mice overexpressing CREMα under control of the CD2 promoter (cremtg mice), which restrains expression mainly to lymphocytes (T, natural killer [NK], and NKT cells), to acute and chronic liver injury models. Already in steady state, Tg CREMα overexpression broadly reduced hepatic immune cell numbers by decreasing their viability, but did not affect immune cell migration or the fibrogenic response to chronic liver injury. Strikingly, cremtg mice developed more severe immune-mediated hepatitis with a higher mortality rate, compared to wild-type (wt) mice, upon concanavalin A (ConA) administration. Unlike in T cells from spleen, CREMα overexpression did not induce a predominant Th17 response in intrahepatic T cells, given that hepatic cremtg CD4+ T cells expressed less interleukin (IL)-17 than wt T cells. Reconstitution of Rag1-/- mice with Crem-/- T cells did not ameliorate ConA hepatitis. Overexpression of CREMα did not influence NK and NKT-cell effector functions either. Interestingly, a subset of monocytic myeloid-derived suppressor cells (MDSCs) also expressed CD2 and CREMα. Cremtg MDSCs isolated from liver expressed reduced inducible nitric oxide synthase and arginase 1 and displayed a reduced T-cell suppressive activity. The adoptive transfer of wt MDSCs was capable of reducing the fulminant immune-mediated liver damage in cremtg mice to wt level.

CONCLUSION

These results suggest compartmental differences of T cell activation pathways between liver and other organs in autoimmunity and define a functional role of CREMα in hepatic monocytic MDSCs for the pathogenesis of immune-mediated liver disease.

Nrf2 and Snail-1 in the prevention of experimental liver fibrosis by caffeine

AIM: To determine the molecular mechanisms involved in experimental hepatic fibrosis prevention by caffeine (CFA).

METHODS: Liver fibrosis was induced in Wistar rats by intraperitoneal thioacetamide or bile duct ligation and they were concomitantly treated with CFA (15 mg/kg per day). Fibrosis and inflammatory cell infiltrate were evaluated and classified by Knodell index. Inflammatory infiltrate was quantified by immunohistochemistry (anti-CD11b). Gene expression was analyzed by quantitative reverse transcription-polymerase chain reaction for collagen I (Col-1), connective tissue growth factor (CTGF), transforming growth factor β1 (TGF-β1), tumor necrosis factor alpha (TNF-α), interleukin-1 (IL-1), IL-6, superoxide dismutase (SOD) and catalase (CAT). Activation of Nrf2 and Snail-1 was analyzed by Western-blot. TNF-α expression was proved by enzyme-linked immunosorbant assay, CAT activity was performed by zymography.

RESULTS: CFA treatment diminished fibrosis index in treated animals. The Knodell index showed both lower fibrosis and necroinflammation. Expression of profibrogenic genes CTGF, Col-1 and TGF-β1 and proinflammatory genes TNF-α, IL-6 and IL-1 was substantially diminished with CFA treatment with less CD11b positive areas. Significantly lower values of transcriptional factor Snail-1 were detected in CFA treated rats compared with cirrhotic rats without treatment; in contrast Nrf2 was increased in the presence of CFA. Expression of SOD and CAT was greater in animals treated with CFA showing a strong correlation between mRNA expression and enzyme activity.

CONCLUSION: Our results suggest that CFA inhibits the transcriptional factor Snail-1, down-regulating profibrogenic genes, and activates Nrf2 inducing antioxidant enzymes system, preventing inflammation and fibrosis.

Regulation of dipeptidyl peptidase 8 and 9 expression in activated lymphocytes and injured liver

AIM

To investigate the expression of dipeptidyl peptidase (DPP) 8 and DPP9 in lymphocytes and various models of liver fibrosis.

METHODS

DPP8 and DPP9 expression were measured in mouse splenic CD4⁺ T-cells, CD8⁺ T-cells and B-cells (B220⁺), human lymphoma cell lines and mouse splenocytes stimulated with pokeweed mitogen (PWM) or lipopolysaccharide (LPS), and in dithiothreitol (DTT) and mitomycin-C treated Raji cells. DPP8 and DPP9 expression were measured in epidermal growth factor (EGF) treated Huh7 hepatoma cells, in fibrotic liver samples from mice treated with carbon tetrachloride (CCl₄) and from multidrug resistance gene 2 (Mdr2/Abcb4) gene knockout (gko) mice with biliary fibrosis, and in human end stage primary biliary cirrhosis (PBC).

RESULTS

All three lymphocyte subsets expressed DPP8 and DPP9 mRNA. DPP8 and DPP9 expression were upregulated in both PWM and LPS stimulated mouse splenocytes and in both Jurkat T- and Raji B-cell lines. DPP8 and DPP9 were downregulated in DTT treated and upregulated in mitomycin-C treated Raji cells. DPP9-transfected Raji cells exhibited more annexin V⁺ cells and associated apoptosis. DPP8 and DPP9 mRNA were upregulated in CCl₄ induced fibrotic livers but not in the lymphocytes isolated from such livers, while DPP9 was upregulated in EGF stimulated Huh7 cells. In contrast, intrahepatic DPP8 and DPP9 mRNA expression levels were low in the Mdr2 gko mouse and in human PBC compared to non-diseased livers.

CONCLUSION

These expression patterns point to biological roles for DPP8 and DPP9 in lymphocyte activation and apoptosis and in hepatocytes during liver disease pathogenesis.

Development of liver fibrosis during aging: effects of caloric restriction

Liver is the central metabolic organ of the body and diet is considered one of the main environmental factors that can impact on aging liver. In the elderly stage liver function is relatively well conserved although there are a variety of not well defined morphological changes related to liver fibrosis which is commonly associated with an inflammatory state. The aim of this paper is to study these alterations during the physiological process of aging in Wistar rats and also test if caloric restriction (CR) could ameliorate them. As fibrosis is associated to hepatic stellate cell (HSC) function we also analyzed these cells during aging. Livers from five groups of male Wistar rats (3-, 8-, 24-months old ad libitum and 8- and 24-months caloric restricted rats) were used in this study. Histological analysis, expression of genes implicated in liver fibrosis and the status of inflammatory step-pathways as p38 mitogen-activated protein kinase (p38-MAPK), c-Jun N-terminal kinase (JNK) and the nuclear factor kappa B (NFkB) isoforms, p50 and p65, in cytosolic and nuclear fractions were performed. During elderly, associated with morphological change of HSC, there is a progressive increase in collagen deposition due to an inhibition in collagen degradation. Higher expression of cytokines and the activation of inflammatory pathways are associated with aging. CR ameliorates these circumstances being more effective when it started in middle age. In conclusion elderly stage is associated to a mild fibrotic and inflammatory state in the liver which could be ameliorated after CR.

[Effect of cordyceps polysaccharide on lipid peroxidation of rats with dimethylnitrosamine-induced liver fibrosis]

OBJECTIVE

To observe the pharmacological effect of Cordyceps polysaccharide on dimethylnitrosamine (DMN)-induced liver fibrosis in rats.

METHOD

DMN rat liver fibrosis model was established and divided into the normal group (N, n = 6), the model group (M, n = 11), the Cordyceps polysaccharide group (C, n = 8) and the colchicine group (Q, n = 9). During the modeling for four weeks, Cordyceps polysaccharide (60 mg x kg(-1)) and colchicine (0.1 mg x kg(-1)) were orally administered for three weeks, while the model and normal groups were given disinfected water of the same amount.

OBSERVATION

serum ALT, AST, GGT and Alb, TBil content; content of hydroxyproline (Hyp) in liver tissues; liver pathology and collagen staining; SOD activity and MDA, GSH, GSH-Px in liver tissues; protein expression of proliferating cell nuclear antigen (PCNA) in liver tissues.

RESULT

Serum ALT, AST, GGT, TBil significantly increased, and A1b decreased significantly in the model group. Hepatic Hyp significantly increased in the model group, whereas the index remarkably decreased in the Cordyceps polysaccharide group and the colchicine group. HE staining: the structure of normal hepatic lobules was damaged, with hepatocytes tumefaction and proliferation of connective tissues in portal tracts in the model group, while the Cordyceps polysaccharide group and the colchicine group recorded notable reduction in above pathological changes. Collagen staining: the model group showed hepatic lobule fibrous septum and many intact pseudolobules; while the Cordyceps polysaccharide group and the colchicine group witnessed decrease in collagen deposition. The model group showed significant decrease in SOD, GSH-Px and GSH and increase in MDA, whereas the Cordyceps polysaccharide group and the colchicine group recorded notable growth in GSH and GSH-Px. The model group showed significant decrease in protein expression of PCNA in liver tissues, while the Cordyceps polysaccharide group and the colchicine group showed significant reduction.

CONCLUSION

Cordyceps polysaccharide can significantly inhibit DMN-induced liver fibrosis and lipid peroxidation in rats.

Loss of A(1) adenosine receptor attenuates alpha-naphthylisothiocyanate-induced cholestatic liver injury in mice

Cholestasis has limited therapeutic options and is associated with high morbidity and mortality. The A(1) adenosine receptor (A(1)AR) was postulated to participate in the pathogenesis of hepatic fibrosis induced by experimental extrahepatic cholestasis; however, the contribution of A(1)AR to intrahepatic cholestatic liver injury remains unknown. Here, we found that mice lacking A(1)AR were resistant to alpha-naphthyl isothiocyanate (ANIT)-induced liver injury, as evidenced by lower serum liver enzyme levels and reduced extent of histological necrosis. Bile acid accumulation in liver and serum was markedly diminished in A(1)AR(-/-) mice compared with wild-type (WT) mice. However, biliary and urinary outputs of bile acids were significantly enhanced in A(1)AR(-/-) mice. In the liver, mRNA expression of genes related to bile acid transport (Bsep and Mdr2) and hydroxylation (Cyp3a11) was increased in A(1)AR(-/-) mice. In the kidney, A(1)AR deficiency prevented the decrease of glomerular filtration rate caused by ANIT. Treatment of WT mice with A(1)AR antagonist DPCPX also protected against ANIT hepatotoxicity. Our results indicated that lack of A(1)AR gene protects mice from ANIT-induced cholestasis by enhancing toxic biliary constituents efflux through biliary excretory route and renal elimination system and suggested a potential role of A(1)AR as therapeutic target for the treatment of intrahepatic cholestasis.

Effects of the administration of pentoxifylline and prednisolone on the evolution of portal fibrogenesis secondary to biliary obstruction in growing animals: immunohistochemical analysis of the expression of TGF-β and VEGF

OBJECTIVE

During the neonatal and infancy periods, some chronic liver diseases may lead to progressive hepatic fibrosis, which is a condition that can ultimately result in the loss of organ function and severe portal hypertension necessitating hepatic transplantation. In a previous report, pharmacological interventions were demonstrated to modulate hepatic fibrosis induced by bile duct ligation in young rats. The administration of pentoxifylline or prednisolone, or the combination of both, resulted in reduced fibrogenesis in portal spaces. The objectives of the present study were to evaluate the expression of transforming growth factor β and vascular endothelial growth factor after bile duct ligation in young rats and to assess the effect of those same drugs on cytokine expression.

METHODS

In this experimental study, 80 young rats (21 or 22 days old) were submitted either to laparotomy and common bile duct ligation or to sham surgery. The animals were allocated into four groups according to surgical procedure, and the following treatments were administered: (1) common bile duct ligation + distilled water, (2) sham surgery + distilled water, (3) common bile duct ligation + pentoxifylline, or (4) common bile duct ligation + prednisolone. After 30 days, a hepatic fragment was collected from each animal for immunohistochemical analysis using monoclonal antibodies against transforming growth factor β and vascular endothelial growth factor. Digital morphometric and statistical analyses were performed.

RESULTS

The administration of pentoxifylline reduced the transforming growth factor β-marked area and the amount of transforming growth factor β expressed in liver tissue. This effect was not observed after the administration of prednisolone. There was a significant reduction in vascular endothelial growth factor expression after the administration of either drug compared with the non-treatment group.

CONCLUSIONS

The administration of pentoxifylline to cholestatic young rats resulted in the diminished expression of transforming growth factor β and vascular endothelial growth factor in liver tissue. The administration of steroids resulted in the diminished expression of vascular endothelial growth factor only. These pathways may be involved in hepatic fibrogenesis in young rats submitted to bile duct ligation and exposed to pentoxifylline or prednisolone.

Interleukin-17 signaling in inflammatory, Kupffer cells, and hepatic stellate cells exacerbates liver fibrosis in mice

BACKGROUND & AIMS

Interleukin (IL)-17 signaling has been implicated in lung and skin fibrosis. We examined the role of IL-17 signaling in the pathogenesis of liver fibrosis in mice.

METHODS

Using cholestatic and hepatotoxic models of liver injury, we compared the development of liver fibrosis in wild-type mice with that of IL-17RA(-/-) mice and of bone marrow chimeric mice devoid of IL-17 signaling in immune and Kupffer cells (IL-17RA(-/-) to wild-type and IL-17A(-/-) to wild-type mice) or liver resident cells (wild-type to IL-17RA(-/-) mice).

RESULTS

In response to liver injury, levels of Il-17A and its receptor increased. IL-17A increased appeared to promote fibrosis by activating inflammatory and liver resident cells. IL-17 signaling facilitated production of IL-6, IL-1, and tumor necrosis factor-α by inflammatory cells and increased the expression of transforming growth factor-1, a fibrogenic cytokine. IL-17 directly induced production of collagen type I in hepatic stellate cells by activating the signal transducer and activator of transcription 3 (Stat3) signaling pathway. Mice devoid of Stat3 signaling in hepatic stellate cells (GFAPStat3(-/-) mice) were less susceptible to fibrosis. Furthermore, deletion of IL-23 from immune cells attenuated liver fibrosis, whereas deletion of IL-22 exacerbated fibrosis. Administration of IL-22 and IL-17E (IL-25, a negative regulator of IL-23) protected mice from bile duct ligation-induced liver fibrosis.

CONCLUSIONS

IL-17 induces liver fibrosis through multiple mechanisms in mice. Reagents that block these pathways might be developed as therapeutics for patients with cirrhosis.

[Inhibitory effect of total flavonoids of Malus hupehensis on hepatic fibrosis induced by Schistosoma japonicum in mice]

OBJECTIVE

To investigate the effects of total flavonoids of Malus hupehensis on hepatic fibrosis in mice induced by Schistosoma japonicum.

METHODS

The mice model of hepatic fibrosis which infected by cercariae of S. japonicum were randomly divided into 6 groups: Group A as a blank control, Group B as a model, Group C as a positive control by complex liver soften tablet of turtle, Group D, E, F treated with a high dose of 114 mg/(kg x d), middle dose of 57 mg/(kg d), and low dose of 28.5 mg/(kg x d) of total flavonoids of Malus hupehensis, respectively. Every group had 10 mice. Each group of C, D, E, F was orally given praziquantel at a dose of 500 mg/(kg x d) for 2 d, on 42 d after the infection, and then administered with total flavonoids of Malus hupehensis for 60 d. Group A and B were orally given with sodium chloride. All the mice were killed at the end of the administration. Serum hyaluronic acid (HA), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were detected; hydroxyproline in liver tissues was detected; areas of egg granuloma and degrees of hepatic fibrosis were observed via HE and Masson staining.

RESULTS

Compared with the blank control Group A, the egg granuloma appeared obviously, the collagen deposit and fibrosis occurred in liver tissues of Group B, C, D, E, F. The levels of ALT, AST, HA in sera and HYP in liver tissues were significantly higher (P < 0.05 or P < 0.01). However, the levels of ALT, AST, HA and HYP in the high, middle and low dose groups of total flavonoids were significantly lower than those in the model Group B (P < 0.05 or P < 0.01), the areas of egg granuloma, the collagen deposits and the degrees of hepatic fibrosis in Group C, D, E, F were significantly lower than those in the model Group B.

CONCLUSION

The total flavonoids of Malus hupehensis have an obviously inhibitory effect on the hepatic fibrosis induced by Schistosomajaponicum infection.

Epithelial-mesenchymal transition in chronic liver disease: fibrogenesis or escape from death?

The possibility that epithelial-mesenchymal transition (EMT) could contribute to hepatic fibrogenesis in chronic liver diseases as reported in other organs, particularly the kidney, reinforced the concept that activated hepatic stellate cells were not the only key players in the hepatic fibrogenic process and that other cell types, either hepatic (i.e. portal fibroblast) or extrahepatic (bone marrow-derived cells and circulating fibrocytes) could contribute to this process. The possibility of the rapid mobilization of a large amount of fibrogenic cells by EMT after liver tissue injury made this phenomenon a relevant and suitable target for anti-fibrogenic strategies. Following an initial enthusiasm for the discovery of this novel pathway in fibrogenesis and the publication of a several highly quoted papers, more recent research has started to cast serious doubts upon the real relevance of this phenomenon in human fibrogenetic disorders. The debate on the authenticity of EMT or at least on its real contribution to the fibrogenic process has become very animated, sometimes reaching levels of "religious" integralism. The overall result is a general confusion on the meaning and on the definition of several key aspects. The aim of this article is to analyze and discuss the evidence supporting or confuting this possibility in order to reach reasonable and useful conclusions.

Development of a large animal model of cirrhosis and portal hypertension using hepatic transarterial embolization: a study in swine

PURPOSE

To develop a clinically relevant porcine model of liver cirrhosis with portal hypertension by means of hepatic transarterial embolization.

MATERIALS AND METHODS

Institutional animal care and use committee approval was obtained for all experiments. Pigs received transcatheter arterial infusion of a 3:1 mixture of iodized oil and ethanol into the hepatic artery in volumes of 16 mL in group 1 (n = 4), 28 mL in group 2 (n = 4), and 40 mL in group 3 (n = 4) with intent of bilobar distribution. Hepatic venous pressure gradient (HVPG) measurement, liver function tests, and volumetry were performed at baseline, at 2 weeks, and before necropsy.

RESULTS

Cirrhosis was successfully induced in three animals that received 16 mL of the embolic mixture and in all four animals that received 28 mL. The animals in the 40-mL group did not recover from the procedure and were euthanized within 48 h. Increases in HVPG after 6-8 weeks versus baseline reached statistical significance (P < .05). Correlation between degree of fibrosis and volume of embolic agent did not reach statistical significance, but there was a trend toward increased fibrosis in the 28-mL group compared with the 16-mL group.

CONCLUSIONS

Transcatheter hepatic arterial embolization can be used to create a reliable and reproducible porcine model of liver cirrhosis and portal hypertension.

The role of lipophilic bile acids in the development of cirrhotic cardiomyopathy

Marked hemodynamic changes occur in humans and experimental animals with cirrhotic liver disease. In the heart, basal contractility, responsiveness to beta-adrenoceptor activation, and excitation-contraction coupling (ECC) are negatively affected in models of cirrhosis and portal hypertension with portosystemic shunting (PVS), and comprise what has been called cirrhotic cardiomyopathy. These effects are accompanied by elevated circulating levels of bile acids. We investigated whether elevated bile acids act as a myocardial toxicant by exposing cardiac muscle in vitro to bile acids and compared these results with two models of cirrhotic cardiomyopathy with elevated bile acids: CCl4-induced cirrhosis and PVS. Cholic acid, a lipophilic bile acid, produced a decrease in basal cardiac contractility and responsiveness to beta-adrenoceptor activation, both of which appeared to result from altered ECC. beta-Adrenoceptor density and signaling were unaffected. Acutely, ursodeoxycholic acid, a more hydrophilic bile acid, had no effect. Cirrhosis produced a decrease in basal force, depressed beta-adrenoceptor responsiveness, and altered ECC similar to cholic acid. However, cirrhosis also altered beta-adrenoceptor signaling including decreases in cyclic AMP formation, expression of the stimulatory G protein, GS, and beta-adrenoceptor density. Displacement of lipophilic bile acids by chronic administration of ursodeoxycholic acid to rats during the development of cirrhotic cardiomyopathy produced by PVS produced attenuation of the effect on ECC. These results suggest a possible role for lipophilic bile acids in some, but not all of the myocardial consequences of chronic portal vein stenosis and CCl4-induced cirrhosis.

Disruption of the growth hormone--signal transducer and activator of transcription 5--insulinlike growth factor 1 axis severely aggravates liver fibrosis in a mouse model of cholestasis

Growth hormone (GH) resistance and low serum levels of insulinlike growth factor 1 (IGF-1) are common features in human liver fibrosis and cirrhosis. Signal transducer and activator of transcription 5 (STAT5) controls several vital functions in the liver, including GH-mediated transcription of IGF-1. To investigate the role of STAT5 in liver fibrogenesis, we specifically deleted the Stat5a/b locus both in hepatocytes and cholangiocytes in the multidrug resistance gene 2 knockout (Mdr2(-/-)) mouse model of cholestasis. Double knockout mice develop an early and severe liver fibrosis phenotype, accompanied by perturbed expression of key regulators of bile acid homeostasis. Deletion of Stat5 resulted in GH resistance, and IGF-1 levels in serum were undetectable. We could observe reduced expression of important hepatoprotective genes, such as epidermal growth factor receptor (Egfr), hepatocyte nuclear factor 6 (Hnf6), prolactin receptor (Prlr), and leukemia inhibitory factor receptor (Lifr) as well as increased numbers of apoptotic hepatocytes.

CONCLUSION

Our data suggest that loss of STAT5 sensitizes hepatocytes to bile acid-induced damage and apoptosis caused by disruption of GH-induced transcription of Igf-1 and down-regulation of hepatoprotective genes. These findings could contribute to the understanding of liver fibrosis and future treatment strategies for liver fibrosis.

[Comparison of the pathogenesis of liver fibrosis induced by pig serum exposure and bile duct ligation in rats]

OBJECTIVE

To observe the occurrence and progression of liver fibrosis induced by pig serum exposure and bile duct ligation, and analyze the relationship between hepatic inflammation and liver fibrosis.

METHODS

Chronically immune-mediated liver fibrosis was induced in rats by weekly injection of pig serum (IPS) into the peritoneal cavity at 3 ml/kg for 12 weeks. Cholestatic fibrosis was induced by common bile duct ligation (BDL). The Knodell score was used to evaluate the histological changes in the liver, and immunohistochemistry was performed using anti-SMA, anti-ED1, anti-CK7, and anti-CD45 antibodies. Quantitative real time PCR (qPCR) analysis was employed to quantify the mRNA expression of the genes related to inflammation, including interleukin-1beta (IL-1beta), IL-6, monocyte chemotactic protein-1, tumor necrosis factor-alpha, regulated upon activation normal T cell expressed and secreted (RANTES), transforming growth factor-beta, platelet-derived growth factor A, as well as the genes associated with fibrogenesis, namely collagen 1, alphaSMA, MMP-9 and TIMP-1.

RESULTS

Knodell scores for periportal necrosis, intralobular degeneration and focal necrosis, and portal inflammation were all significantly higher in the BDL group than in the IPS group (P<0.01), whereas the scores for fibrosis was higher in the IPS group (P<0.05). Immunohistochemistry showed obvious inflammation with numerous alphaSMA-positive cells in the liver of the rats in BDL group; the liver of the rats in IPS group showed numerous alphaSMA-positive myofibroblasts with limited inflammatory cell infiltration. qPCR demonstrated a significant up-regulation of the genes related to extracellular matrix remodeling such as collagen 1 (P<0.01), alphaSMA (P<0.01), MMP-9 (P<0.01) and TIMP-1 (P<0.01) in the rat liver in IPS group compared with those in the normal control group, and the mRNA expressions of the inflammation-related cytokines, except for RANTES, were comparable with those in the control. In contrast, the BDL group showed a significant up-regulation of all the pro-inflammatory genes examined with also increased expression of the fibrogenesis-related genes (P<0.05).

CONCLUSION

Liver fibrosis induced by IPS is characterized by active ECM remodeling in the absence of obvious inflammation, indicating that chronic development of liver fibrosis can be independent of active hepatic inflammation. BDL-induced liver fibrosis highlights obvious inflammation and fibrous proliferation in the liver.

[Effect of beta-catenin on the activation of hepatic stellate cells induced by transforming growth factor-beta1]

OBJECTIVE

To investigate the effect of beta-catenin on the activation of hepatic fibrosis by transforming growth factor-beta 1 (TGFbeta1).

METHODS

The recombinant expression plasmids pcDNA3.1(+)-beta-catenin and pEGFP-N1 were cotransfected into cultured HSC-T6 cells. The expression of smad3, beta-catenin and alpha-SMA, beta-catenin protein in TGFbeta1 treated HSC-T6 cells were detected by RT-PCR and Western-blot.

RESULTS

The expression of smad3 and beta-catenin in the co-transfected cells was higher than that in the untransfected cells (smad3 mRNA were 0.642 +/- 0.011, 0.501 +/- 0.021, 0.511 +/- 0.019, 0.356 +/- 0.017, respectively, F = 135.304, P < than 0.05. beta-catenin mRNA were 0.783 +/- 0.021, 0.543 +/- 0.033, 0.538 +/- 0.024, 0.212 +/- 0.019, respectively, F = 267.340, P < than 0.05. smad3 protein were 0.892 +/- 0.012, 0.124 +/- 0.011, 0.130 +/- 0.021, 0.003 +/- 0.001, F = 2823.813, P < l than 0.05. beta-catenin protein were 0.921 +/- 0.020, 0.210 +/- 0.010, 0.208 +/- 0.008, 0.002 +/- 0.001, respectively, F = 3440.982, P < than 0.05). The expression of beta-catenin and smad3 protein had a positive correlation with the level of alpha-SMA protein in cells (r = 0.901, P < than 0.01; r = 0.939, P < than 0.01).

CONCLUSIONS

Expression of smad3/alpha-SMA/beta-catenin is increased in the cultured HSC-T6 cells transfected by beta-catenin gene, especially when the transfected cells are stimulated by TGFbeta1. Our data suggest that beta-catenin could aggravate hepatic fibrosis induced by TGFbeta1.

Paraoxonase-1 is related to inflammation, fibrosis and PPAR delta in experimental liver disease

BACKGROUND

Paraoxonase-1 (PON1) is an antioxidant enzyme synthesized by the liver. It protects against liver impairment and attenuates the production of the pro-inflammatory monocyte chemoattractant protein-1 (MCP-1). We investigated the relationships between hepatic PON1 and MCP-1 expression in rats with liver disease and explored the possible molecular mechanisms involved.

METHODS

CCl4 was administered for up to 12 weeks to induce liver damage. Serum and hepatic levels of PON1 and MCP-1, their gene and protein expression, nuclear transcription factors, and histological and biochemical markers of liver impairment were measured.

RESULTS

High levels of PON1 and MCP-1 expression were observed at 12th week in the hepatocytes surrounding the fibrous septa and inflammatory areas. CCl4-administered rats had an increased hepatic PON1 concentration that was related to decreased gene transcription and inhibited protein degradation. Decreased PON1 gene transcription was associated with PPARdelta expression. These changes were accompanied by increased hepatic MCP-1 concentration and gene expression. There were significant direct relationships between hepatic PON1 and MCP-1 concentrations (P = 0.005) and between PON1 and the amount of activated stellate cells (P = 0.001).

CONCLUSION

Our results from this experimental model suggest a hepato-protective role for PON1 against inflammation, fibrosis and liver disease mediated by MCP-1.

Chronic High Doses of Thioacetamide Followed by Vitamin A Modify Dolichol, Dolichol Isoprenoids, and Retinol Content in Rat Liver Cells

Our line of researches follows the hypothesis that dolichol and retinol metabolism might be interrelated and involved in liver fibrosis. To this end, in this study rats were subjected to chronic treatment with thioacetamide (TAA) (300 mg/L liquid diet) for 1 and 2 months and, after liver damage had occurred, supplemented with vitamin A before sacrifice. Dolichol, dolichol isoprene units, and retinol content were determined in isolated parenchymal and sinusoidal liver cells (hepatic stellate cells; Kupffer cells; sinusoidal endothelial cells). Dolichol increased in hepatocytes after TAA treatment, with or without vitamin A. Dolichol decreased in the other cells. Retinol in general decreased. In hepatocytes, retinol decreased only on normal nutrition, while the vitamin A load was taken up normally. The percentages of dolichol isoprene units (Dol-16 to Dol-20, in rats) confirm that Dol-18, which was not modified in percentage by TAA on normal nutrition, did not increase after vitamin A, as it did in control cells (7-12%). The behavior of Dol-18 was similar in all the cells studied. Vitamin A might reveal a latent damage produced by TAA on dolichol homologues. These data support previous hypotheses that the action of TAA depends on the administration modality, the dosage, and the diet, and that Dol-18 might have different functions and compartmentalization in the cells. Furthermore, the results support the hypothesis that dolichol chain length might be interrelated with retinol metabolism, perhaps through their metabolites.

Coagulation status modulates murine hepatic fibrogenesis: implications for the development of novel therapies

BACKGROUND

There is strong evidence demonstrating that coagulation system activation contributes to wound healing and promotes organ fibrosis. Several epidemiological studies have now shown that prothrombotic status, including carriage of the factor (F)V Leiden mutation, is associated with rapid progression of hepatic fibrosis.

OBJECTIVES

To assess the effect of a procoagulant state on progression of hepatic fibrosis in a controlled environment and to test whether anticoagulation could attenuate fibrogenesis.

METHODS

We investigated the effects of coagulation status on liver fibrosis development in a mouse model of chronic toxic liver injury. Prothrombotic FV Leiden mutant mice, C57BL/6 control animals and anticoagulated mice were studied after chronic exposure to carbon tetrachloride.

RESULTS

Carriage of the FV Leiden mutation caused a significant increase in hepatic fibrosis. Anticoagulation with warfarin significantly reduced fibrosis progression in wild-type mice but was less effective against the profibrotic FV Leiden mutation. Changes in the fibrosis scores were mirrored by changes in liver hydroxyproline content and hepatic stellate cell activation detected by alpha-smooth muscle actin expression.

CONCLUSIONS

These results demonstrate that coagulation status has a strong influence on hepatic fibrogenesis. It is likely that thrombin signaling through the proteinase-activated receptor 1 (PAR(1)) receptor expressed on hepatic stellate cells is responsible for this relationship. These results represent the first reported use of anticoagulation to slow hepatic fibrogenesis and suggest a potential novel anti-fibrotic therapeutic approach for the future.

Diagnosis and measurement of liver fibrosis by MRI in bile duct ligated rats

The noninvasive evaluation of liver fibrosis is a major clinical goal in liver diseases. Our aim was to identify MRI parameters to quantify liver fibrosis in vivo in an animal model of liver fibrosis with slight inflammation. We evaluated serum hyaluronate, liver hydroxyproline, area of liver fibrosis (image analysis), and 1.5-T MRI in 10 sham rats and 24 bile duct ligated rats with different stages of liver fibrosis. Liver signal intensity (SI)/muscle SI ratio and liver relaxation times (rT) were measured on T1 and T2 weighted sequences at different echo (TE) or recovery (RT) times of MRI. Among the 66 MRI parameters tested, the highest correlation with the area of fibrosis was observed for rT2 (r=0.78, P < 0.01). The area of liver fibrosis was independently predicted by five MRI variables (adjusted R (2)=0.78, with R (2)=0.64 for rT2 and rT1). Diagnostic accuracy for liver fibrosis was 100% using two variables: liver/muscle SI ratio on T2 at 30-ms TE and liver/muscle SI ratio on T1 at 50-ms RT. We conclude that in this animal model, fibrosis could be diagnosed with an accuracy of 100% using two MRI parameters. The quantification of liver fibrosis was very accurate either with only one MRI parameter (r=0.78 for rT2) or with five parameters (r=0.90) in this cholestatic model.

[Regulatory effects of RhoGTPase on transition of liver sinusoidal capillarization: experiment with mice of schistosomal hepatic fibrosis]

OBJECTIVE

To investigate the regulatory effects of RhoGTPase on the transition of liver sinusoidal endothelial cells and the potential mechanism thereof on the sinusoidal capillarization in schistosomal hepatic fibrosis.

METHODS

Eight-eight mice underwent abdominal infection of schistosomal cercaria so as to establish liver fibrosis models. 13 weeks later the mice were divided into 5 groups: Group A (normal control group, n = 10), Group B (group of schistosomiasis, n = 24), Group C (anti-schistosoma control group, treated with biltricide), Group D (group of schistosomiasis + hydroxyfasudil, treated with hydroxyfasudil since the week 14, n = 18), and Group E (biltricide + hydroxyfasudil, treated with biltricide since week 13 and added with hydroxyfasudil since week 14, n = 18). The mice in Group A and 6 mice of Group B were killed in week 13, and 6 mice of Groups B, C, D, and E were killed in weeks 16, 19, and 21 each. The livers were taken out to undergo electron microcopy. Immunohistochemistry was used to detect the expression of p-moesin, connective tissue growth factor (CTGF), RhoA, collagen IV (Col IV), and laminin (LN) protein expressions were assessed by Western blotting, and RT-PCR was used to detect the mRNA expression of CTGF, RhoA, and ROCK II.

RESULTS

Compared with Group A, the mRNA levels of RhoA, ROCK II, and CTGF were significantly increased (all P < 0.05) and the protein expression levels of p-moesin, CTGF, RhoA, Col IV, and LN were significantly increased (all P < 0.05) in Group B. After intervention with biltricide and/or hydroxyfasudil, the CTGF mRNA expression was significantly decreased (P < 0.05) in Group E in week 16 and the protein expression levels of CTGF, Col IV, and LN were decreased (all P < 0.05) compared with other groups, and the expression of p-moesin of Group E was significantly lower than that of Group D (P < 0.05). Electron microcopy showed that the liver sinusoids of the mice in Group E was significantly better compared with the other groups, and there was no significant difference between Groups B and D.

CONCLUSION

An upregulation of RhoGTPase that contributes to increased CTGF expression and phosphorylation of moesin may induce a transition of liver sinusoidal endothelial cells in schistosomiasis.

Grape seed extract reduces oxidative stress and fibrosis in experimental biliary obstruction

BACKGROUND AND AIM

The aim of this study was to assess the protective effect of grape seed extract (GSE) against oxidative liver injury and fibrosis induced by biliary obstruction in rats.

METHODS

Wistar albino rats were divided into four groups; control (C), GSE-treated, bile duct ligated (BDL), and BDL and GSE-treated (BDL + GSE) groups. GSE was administered at a dose of 50 mg/kg a day orally for 28 days. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) levels were determined to assess liver function and tissue damage, respectively. Tumor necrosis factor-alpha (TNF-alpha) and antioxidant capacity (AOC) were assayed in plasma samples. Liver tissues were taken for determination of the hepatic malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and collagen content. Production of reactive oxidants was monitored by chemiluminescence (CL) assay.

RESULTS

Serum AST, ALT, LDH and plasma TNF-alpha were elevated in the BDL group as compared to the control group and were significantly decreased with GSE treatment. Plasma AOC and hepatic GSH level, depressed by BDL, was elevated back to the control level in the GSE-treated BDL group. Increases in tissue MDA level, MPO activity and collagen content due to BDL were also attenuated by GSE treatment. Furthermore, luminol and lucigenin CL values in the BDL group increased dramatically compared to the control and were reduced by GSE treatment.

DISCUSSION

These results suggest that GSE protects the liver from oxidative damage following bile duct ligation in rats. This effect possibly involves the inhibition of neutrophil infiltration and lipid peroxidation; thus, restoration of oxidant and antioxidant status in the tissue.

Genistein decreases liver fibrosis and cholestasis induced by prolonged biliary obstruction in the rat

Fibrosis accompanies most chronic liver disorders and is a major factor contributing to hepatic failure. Therefore, the need for an effective treatment with the aim of modifying the clinical course of this disease is evident. The aim of this work is to determine whether genistein, which has been shown to modulate the physiology and pathophysiology of liver, is able to decrease experimental liver fibrosis and cholestasis. In male Wistar rats, the common bile duct was ligated. Administration of genistein (5 microg rat-1, day-1, p.o.) began four weeks after biliary obstruction and continued for a further four weeks. The liver was used for histological and ultrastructural analysis and for collagen quantification (hydroxyproline content). The degradation of Matrigel(R) and collagen type I was determined in homogenized liver. Bilirubins and enzyme activities were measured in serum. Genistein was able to improve normal liver histology, ultrastructure, collagen content, and biochemical markers of liver damage. It also increased Matrigel(R) and collagen type I degradation. In summary, the present report shows that genistein inhibits the fibrosis and cholestasis induced by prolonged biliary obstruction in the rat. Genistein has therapeutic potential against liver fibrosis.

Erdosteine treatment attenuates oxidative stress and fibrosis in experimental biliary obstruction

Oxidative stress, in particular lipid peroxidation, induces collagen synthesis and causes fibrosis. The aim of this study was to assess the antioxidant and antifibrotic effects of erdosteine on liver fibrosis induced by biliary obstruction in rats. Liver fibrosis was induced in Wistar albino rats by bile duct ligation (BDL). Erdosteine (10 mg/kg, orally) or saline was administered for 28 days. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) levels were determined to assess liver functions and tissue damage, respectively. Pro-inflammatory cytokines, TNF-alpha, IL-1beta and IL-6 and antioxidant capacity (AOC) were assayed in plasma samples. Liver tissues were taken for determination of malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and collagen content. Production of reactive oxidants was monitored by chemiluminescence assay. Serum AST, ALT, LDH, and plasma cytokines were elevated in the BDL group as compared to controls and were significantly decreased by erdosteine treatment. Hepatic GSH level and plasma AOC, depressed by BDL, were elevated back to control level with erdosteine treatment. Furthermore, hepatic luminol and lucigenin chemiluminescence (CL), MDA level, MPO activity and collagen content in BDL group increased dramatically compared to control and reduced by erdosteine treatment. Since erdosteine administration alleviated the BDL-induced oxidative injury of the liver and improved the hepatic functions, it seems likely that erdosteine with its antioxidant and antifibrotic properties, may be of potential therapeutic value in protecting the liver fibrosis and oxidative injury due to biliary obstruction.

[Inhibitory effect of angiotensin blockade on hepatic fibrosis in common bile duct-ligated rats]

BACKGROUNDS AND AIMS

Angiotensin receptors are found on hepatic stellate cells, which participate in hepatic fibrosis. Therefore, it is presumed that angiotensin has a role in hepatic fibrosis. The aim of this study was to evaluate the effects of angiotensin blockade on inhibition of hepatic fibrosis in cirrhotic rat model.

MATERIAL AND METHODS

Cirrhosis with portal hypertension was produced by common bile duct ligation (BDL) in the adult Sprague-Dawley rats. They were classified into 4 groups (each group n=6) as follows; G1: BDL without drug, G2: BDL+captopril 100 mg/kg/day beginning 2 weeks after BDL, G3: BDL+captopril 100 mg/kg/day, starting just after BDL, G4: BDL+losartan 10 mg/kg/day, starting just after BDL. After 4 weeks following BDL, hepatic fibrosis was histomorphologically analyzed by Batts & Ludwig score. alpha smooth muscle actin by immunohistochemical stain, hydroxyproline contents of liver tissue by spectrophotometry and expression of collagen, procollagen, and TGF-beta by real-time PCR were measured.

RESULTS

Batts & Ludwig score were 3.8, 3.0, 2.6,and 2.6 in G1, G2, G3, and G4, respectively. The expression of alpha-SMA was significantly lower in G3 and G4 than in G1; 11.9%, 10.9%, 2.6%, and 1.1% in G1, G2, G3, and G4, respectively (p<0.05). The concentration of hydroxyproline (microg/g liver tissue) was lower in G3 and G4 compared with G1 (p<0.05). Also, the administration of angiotensin blockade just after BDL significantly reduced the expression of collagen, procollagen, and TGF-beta mRNA.

CONCLUSIONS

Angiotensin blockades are effective in the prevention of hepatic fibrosis in BDL rats.

The role of food restriction on CCl4-induced cirrhosis model in rats

Effects of food restriction on susceptibility to the toxic effect of some chemicals are controversial. In order to identify an exposure model that could maximize cirrhosis and minimize mortality rate, this study aimed to evaluate the effect of food restriction on tetrachloride carbon (CCl(4))-induced cirrhosis model in rats. Fifty-three male Wistar rats received CCl(4) 0.25 ml/kg weekly intragastrically once a week. Thirty-three had 44% food restriction (group 1); 10 rats had 25% food restriction (group 2); and 10 rats received ad libitum food (group 3). After 10 weeks, the animals were sacrificed and liver sections were collected for histology. Of the 53 animals enrolled for the study, 22 (41.5%) died before completing 10-week CCl(4). Mortality rate was significantly higher in group 1 compared to other groups (p<0.05). Cirrhosis was significantly more prevalent in group 1 than in group 3 (p<0.01), but without significant difference between groups 1 and 2 (p=0.624). We concluded that food restriction is an important issue to be considered when establishing a CCl(4)-induced cirrhosis model in rats. Moreover, there is an ideal range of food intake that predisposes to liver damage without increasing mortality leading to a more effective model.

LPS exacerbates endothelin-1 induced activation of cytosolic phospholipase A2 and thromboxane A2 production from Kupffer cells of the prefibrotic rat liver

BACKGROUND/AIMS

Thromboxane A2 (TXA2) has been suggested to play a significant role in the development of portal hypertension in fibrosis, and Kupffer cell (KC) derived TXA2 has been shown to mediate the hyperresponsiveness of the portal circulation to the vasoconstrictive actions of endothelin-1 (ET-1) during endotoxemia. The aim of this study was to determine whether the double stresses of prefibrotic changes and endotoxemia additively activate KC to increase release of TXA2 in response to ET-1, resulting in elevated portal resistance.

METHODS

One week Bile duct ligation (BDL) rats and sham-operated controls were subjected to isolated liver perfusions following LPS or saline for 6h. In a separate experiment, KC were isolated from BDL or sham rats and incubated with LPS or saline for 6h before the ET-1 treatment.

RESULTS

The double stresses of early fibrosis and LPS resulted in a greater sustained increase in portal pressure in response to ET-1 in BDL rats, and this increase correlated well with the much enhanced release of TXA2 in the perfusate. Media from the cultured KC showed significantly greater TXA2 release in response to ET-1 in BDL group than those in sham group, and LPS exacerbated this effect. Protein levels of cytosolic phospholipase A2 (cPLA2), cyclooxygenase-2, and thromboxane synthase were also significantly elevated in KC from BDL rats. ET-1 produced a marked increase in cPLA2 activation as measured by the phosphorylation of cPLA2 in KC of both BDL and sham groups. LPS greatly exacerbated the activation of cPLA2.

CONCLUSIONS

The data suggest that the double stresses additively activate KC with an upregulation of the key enzymes in the TXA2 biosynthesis and release increased amount of TXA2 via the augmented activation of cPLA2 in response to ET-1, which leads to the increased portal resistance and ultimately hepatic microcirculatory dysfunction.

Partial portal vein ligation plus thioacetamide: a method to obtain a new model of cirrhosis and chronic portal hypertension in the rat

To obtain a new model of chronic portal hypertension in the rat, two classical methods to produce portal hypertension, partial portal vein ligation and the oral administration of thioacetamide (TAA), have been combined. Male Wistar rats were divided into four groups: 1 (control; n = 10), 2 [triple partial portal vein ligation (TPVL); n = 9], 3 (TAA; n = 11), and 4 (TPVL plus TAA; n = 9). After 3 months, portal pressure, types of portosystemic collateral circulation, laboratory hepatic function tests (aspartate aminotransferase, alanine aminotransferase, bilirubin, alkaline phosphatase, and gamma-glutamyl transpeptidase) and liver histology were studied. The animals belonging to group 2 (TPVL) developed extrahepatic portosystemic collateral circulation, associated with mesenteric venous vasculopathy without hepatic destructurization or portal hypertension. Animals from group 3 (TAA) developed cirrhosis and portal hypertension but not extrahepatic portosystemic collateral circulation, or mesenteric venous vasculopathy. Finally, the animals from group 4 (TPVL + TAA) developed cirrhosis, portal hypertension, portosystemic collateral circulation, and mesenteric venous vasculopathy. The association of TPVL and TAA can be used to obtain a model of chronic portal hypertension in the rat that includes all the alterations that patients with hepatic cirrhosis usually have. This could, therefore, prove to be a useful tool to study the pathophysiological mechanisms involved in these alterations.

The effect of aminoguanidine against cholestatic liver injury in rats

We investigated the protective role of aminoguanidine (AG) in rat liver injury induced by chronic biliary obstruction. Secondary biliary cirrhosis was induced by bile duct ligation for 14 days. Swiss albino rats were divided into three groups: Common bile duct ligated (CBDL) rats; Group A, CBDL rats treated with AG as Group B and simple laparotomy group known as the Sham group; Group C. Group B received 200 mg/kg of AG intraperitoneally daily throughout 14 days. The present data showed decreased gama glutamyl transferase (GGT), aspartate aminotransferase (AST), bilirubin and alanine aminotransferase (ALT) levels in the AG treated rats, when compared with CBDL rats (p < 0.05). In the AG treated rats, tissue levels of malondialdehyde (MDA) were significantly lower than that in CBDL rats (p < 0.001). Although the levels of glutathione (GSH) in AG treated rats were higher and myeloperoxidase (MPO) were lower than that in CBDL rats, the difference was not statistically significant (p > 0.05). The levels of interleukin-1alpha (IL-1alpha) and tumor necrosis factor-alpha (TNF-alpha) were significantly lower and although the levels of interleukin-6 (IL-6) were lower in AG treated rats than that in CBDL rats, the difference was not statistically significant. Administration of AG in the rats with biliary obstruction resulted in inhibition of ductular proliferation and portal inflammation. The present study demonstrates that intraperitoneal administration of AG in CBDL rats maintains antioxidant defenses, reduces liver oxidative and cytokine damage and ductular proliferation and portal inflammation. This effect of AG may be useful in the preservation of liver injury in cholestasis.

Influences of reactive oxygen species and nitric oxide on hepatic fibrogenesis

BACKGROUND/AIMS

This study determined the roles of NAD(P)H oxidase, which generates reactive oxygen species (ROS), and of inducible nitric oxide synthase (iNOS), which generates nitric oxide (NO) on the development of hepatic fibrosis in mice.

METHODS

Hepatic fibrosis was produced by carbon tetrachloride administered for 12 weeks in wild-type (WT) mice and in mice with knockout of either the gp91phox subunit of the NAD(P)H complex (gp91phox-/-) or of iNOS (iNOS(-/-)).

RESULTS

Liver fibrosis and hydroxyproline after carbon tetrachloride was lower in gp91phox-/- and in iNOS(-/-) mice than in WT mice. The increase in alpha2(I) collagen mRNA was absent in the gp91phox-/- but not in the iNOS(-/-) mice. Transformation growth factor beta (TGF-beta) mRNA was increased more in the gp91phox-/- than in the WT mice, while in the iNOS(-/-) mice there was no increase in TGF-beta mRNA. 3-Nitrotyrosine was similarly increased by carbon tetrachloride in gp91phox-/- and WT mice, while there was no increase in the iNOS(-/-) mice.

CONCLUSIONS

Deficiencies in NAD(P)H oxidase and in iNOS separately reduce, but do not eliminate carbon tetrachloride-induced liver fibrosis. Likely causes for this inhibitory effects are decreases in the production of ROS in NAD(P)H deficiency and of peroxinitrite radicals in iNOS deficiency.

Cholesterol-fed rabbit as a unique model of nonalcoholic, nonobese, non-insulin-resistant fatty liver disease with characteristic fibrosis

BACKGROUND

The number of patients suffering from metabolic syndrome is increasing rapidly. Metabolic syndrome causes severe pathological changes in various organs, including the liver, and its main phenotype is nonalcoholic fatty liver disease (NAFLD). NAFLD has a broad spectrum ranging from simple fatty change to severe steatohepatitis with marked fibrosis. Recently, several experimental animal models for NAFLD have been proposed. However, most were established by rather artificial conditions such as genetic alteration. In the present study, we tried to establish a unique animal model mimicking some of the physiopathological features of NAFLD using high-cholesterol-fed rabbits.

METHODS

Male rabbits fed with standard rabbit food containing 1% cholesterol for 8 weeks and 12 weeks were compared to controls (six rabbits/group). The weight of food was strictly restricted to 100 g/rabbit per day.

RESULTS

Body weights and fasting plasma insulin levels showed no significant differences among the groups. In contrast, characteristic fine fibrosis was extended from perivenular to pericellular areas, and microvesicular fatty change with ballooning degeneration was observed in perivenular areas in livers of the cholesterol-fed rabbits. Increase of serum cholesterol level, activation of hepatic stellate cells, and exposure to oxidative stress were also recognized.

CONCLUSIONS

Cholesterol-fed rabbits share several physiopathological features of NAFLD. Because this model did not show insulin resistance or obesity, it may be useful for elucidating the mechanism of NAFLD related mainly to hyperlipidemia.

Preventive and therapeutic effects of angiotensin II type 1 receptor blocker on hepatic fibrosis induced by bile duct ligation in rats

BACKGROUND

The aim of this study was to examine the preventive and therapeutic effects of an angiotensin II type 1 receptor blocker, candesartan, on cholestasis-induced liver fibrosis.

METHODS

Candesartan was administered orally for 21 days immediately after bile duct ligation to evaluate its preventive effect, and for 21 days starting 3 weeks after bile duct ligation to evaluate its therapeutic effect. Fibrosis was assessed by measuring hepatic hydroxyproline (Hyp) content. The activated hepatic stellate cells (HSCs) were assessed by alpha-smooth muscle actin (alpha-SMA) immunostaining. The gene expression of collagen I, transforming growth factor-beta1 (TGF-beta1), and connective tissue growth factor (CTGF) in the liver was examined by real-time reverse transcriptase-polymerase chain reaction.

RESULTS

As a preventive effect, candesartan reduced the hepatic Hyp content by 36%, alpha-SMA-positive cells by 65%, hepatic TGF-beta1 content by 35%, and the expression of collagen I by 72%, TGF-beta1 by 67%, and CTGF mRNA by 69%. As a therapeutic effect, candesartan reduced the hepatic Hyp content by 48%, TGF-beta1 content by 54%, and the expression of collagen I by 47%, TGF-beta1 by 43%, and CTGF mRNA by 53%. Significant decreases in lipid peroxidation markers, hepatic thiobarbituric acid-reactive substance, and 4-hydroxy-2-nonenal were observed in candesartan-treated rats.

CONCLUSIONS

Candesartan attenuated liver fibrosis via suppression of collagen I and TGF-beta1 expression, HSC activation, and lipid peroxidation protein, showing its preventive and therapeutic effects on cholestasis-induced liver fibrosis.

Inhibition of aromatase improves nutritional status following portacaval anastomosis in male rats

BACKGROUND/AIMS

The portacaval anastamosis (PCA) rat is a model of the nutritional and endocrine consequences of liver cirrhosis. We hypothesized that failure to gain body weight in the PCA rat was the consequence of low testosterone levels and will be reversed by 4-hydroxyandrostenedione, a specific aromatase inhibitor.

METHODS

Male Sprague-Dawley rats subjected to an end-to-side PCA or sham surgery were administered either 4-hydroxyandrostenedione or vehicle. Food intake, food efficiency, and body weight were measured, animals sacrificed 3 weeks after surgery, visceral organs harvested and plasma sex steroids measured. Hepatic RNA was extracted and dot blots done to quantify the expression of sex hormone dependent enzymes 16alpha hydroxylase and 15beta hydroxylase.

RESULTS

Growth, food intake, food efficiency and plasma testosterone were lower and plasma estradiol higher in PCA than sham rats. Hepatic expression of testosterone driven 16alpha hydroxylase was lower and estradiol driven 15beta hydroxylase higher in PCA rats. These alterations were reversed by 4-hydroxyandrostenedione.

CONCLUSIONS

These observations demonstrate that use of aromatase inhibitor reverses the nutritional and endocrine abnormalities in the PCA rat and suggest that this approach may be useful in cirrhotic patients.

[Effects and comparison of seed oil and sarcocarp oil of Hippophae rhamnoides on rats with experimental hepatocirrhosis]

OBJECTIVE

A study was carried out to investigate the effects of seed oil and sarcocarp oil of Hippophae rhamnoides on rats with experimental hepatocirrhosis, and comparison between the two.

METHOD

A rat model of experimental hepatocirrhosis was set up by feeding CCl4. Different concentration of seed oil and sarcocarp oil of H. rhamnoides were feed to those rats for 45 d, then the changes of activity of ALT in serum and SOD in liver were measured.

RESULT

Both of seed oil and sarcocarp oil can control the increase of ALT in serum and the decrease of SOD evidently, and the effect of seed oil was turn out to be a little better than sarcocarp oil.

CONCLUSION

Seed oil was more effective than sarcocarp oil of H. rhamnoides in alleviating liver injury caused by CCl4.

[Effect of Hovenia dulcis extract on expression of MMP-13 and TIMP-1 in hepatic tissue]

OBJECTIVE

To investigate the effects of Hovenia dulcis extract on mRNA expression of MMP-13 and TIMP-1 mRNA in hepatic tissue in experimental rats.

METHOD

48 male Sprague-Dawley rats were randomly divided into 2 groups: normal group (16) and model group (32), hepatic fibrosis was induced by CCl4 for 6 weeks in rats, 8 rats were sacrificed at the end of the 6th week from every group respectively, HE staining of hepatic tissue was performed; In the model group, rats randomly subdivided into 3 groups: spontaneous recovery group, control group and medication administration group, 8 rats were sacrificed at the end of the 12th week from every group respectively, the mRNA levels of MMP-13 and TIMP-1 in hepatic tissue were assayed by semi-quantitative RT-PCR.

RESULT

The mRNA expression of MMP-13 among the 4 groups were not statistically significant, but the mRNA expression of TIMP-1 among the 4 groups were statiscally significant. The levels of TIMP-1 mRNA were significantly increased in control group and medication administration group compared, with those in the model group (P < 0.05), and reverse effects of medication administration groups were significantly high than those of control group (P < 0.05).

CONCLUSION

Inhibition of the mRNA expression of TIMP-1 may be the mechanism of reversing hepatic fibrosis H. dulcis, for thus collogen degradation system was recoveried gradually.