Concanavalin A-induced Hepatitis In Mice Research Articles

Endogenous αCGRP protects against concanavalin A-induced hepatitis in mice

To evaluate hepatoprotective effect of α-calcitonin gene-related peptide (αCGRP), we compared the susceptibilities of αCGRP−/− and wild-type mice to concanavalin A (Con A)-induced hepatitis. Twelve hours after Con A administration, serum transaminases were markedly higher in αCGRP−/− than wild-type mice, and much more extensive TUNEL-positive lesions and DNA fragmentation were detected in the livers of αCGRP−/− mice. Notably, expression of IL-6 was selectively diminished in αCGRP−/− mice, suggesting that induction of IL-6 during acute inflammatory responses is blunted in αCGRP−/− mice. In addition, primary cultured αCGRP−/− hepatocytes were more susceptible to IFN-γ-induced cell death than hepatocytes from wild-type mice. Administration of exogenous αCGRP reduced the incidence of apoptosis among hepatocytes and endothelial cells. It thus appears that αCGRP exerts a hepatoprotective effect by modulating cytokine expression and preventing apoptosis.

Therapeutic administration of Y-40138, a multiple cytokine modulator, inhibits concanavalin A-induced hepatitis in mice

Concanavalin A-induced hepatitis is often used as a model of liver injury. In this model, plasma tumor necrosis factor-α (TNF-α) level increased in concanavalin A-injected mice. Prophylactic treatment with Y-40138, N-[1-(4-[4-(pyrimidin-2-yl)piperazin-1-yl]methyl phenyl)cyclopropyl] acetamide·HCl, significantly suppressed the increase in plasma TNF-α level. In this study, we compared the effect of Y-40138 with those of pentoxifylline and anti-TNF-α antibody on concanavalin A-induced hepatitis. Prophylactic treatment with pentoxifylline, anti-TNF-α antibody and Y-40138 reduced plasma alanine aminotransferase level. Therapeutic treatment with Y-40138 significantly reduced plasma alanine aminotransferase level, but pentoxifylline and anti-TNF-α antibody did not. Therapeutic treatment with Y-40138 significantly reduced plasma interferon-γ (IFN-γ) and monokine induced by interferon-γ levels. From these results, Y-40138 may be expected as a new class of therapeutic drug for treatment of TNF-α, IFN-γ and/or chemokine-related liver diseases such as alcoholic liver disease.

Role of CPG DNA in concanavalin A-induced hepatitis in mice

Role of CPG DNA in concanavalin A-induced hepatitis in mice

Development of anorexia in concanavalin A-induced hepatitis in mice.

Anorexia that develops in chronic hepatitis is associated with cytokine expression in the brain. Treatment of mice with concanavalin A (12.5 mg/kg, i.v.) elevated the plasma alanine aminotransferase activity at 8.5 h after treatment. Tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta mRNA expression was induced at 6 and 24 h after concanavalin A treatment in both the liver and brain. Treatment of mice with concanavalin A reduced the body weight at 24 h after treatment and this decreased body weight was accompanied by a decreased food intake. Glycyrrhizin (200 mg/kg, i.p.) inhibited the concanavalin A-induced elevation of plasma alanine aminotransferase activity, however, it did not inhibit the concanavalin A-induced decreased body weight. The present results indicate that treatment of mice with concanavalin A caused the development of anorexia and that this anorexia might develop independently of the induction of hepatitis.

A broad-spectrum caspase inhibitor blocks concanavalin A-induced hepatitis in mice.

Fulminant hepatic failure (FHF) is a clinical syndrome resulting from massive death of liver cells or sudden and severe impairment of liver function. The causes of FHF are diverse and the overall mortality is very high. Recently, it became clear that apoptosis of hepatocytes is the critical cause of acute hepatic failure in FHF. It is well known that a family of cysteine proteases called caspase is one of the key mediators of the apoptotic pathway. Thus, caspases are attractive potential targets for the treatment of disorders resulting from excessive apoptosis. In this report, we examined the activity of a new caspase inhibitor, Xyz 033 mp. This nonpeptide inhibitor showed broad-spectrum caspase-inhibiting activity and protected primary rat hepatocytes from apoptotic death. In a mouse model of FHF induced by concavalin A (Con A), Xyz 033 mp suppressed elevated AST and ALT and specifically reduced IL-1 beta concentration. Also, Xyz 033 mp rescued mice from lethal experimental hepatitis induced by Con A. In addition, histological examinations indicated that Xyz 033 mp protected hepatocytes from the fatal apoptogenic effect of Con A. These results suggest that Xyz 033 mp may be a candidate therapeutic agent for FHF caused by massive apoptotic death of hepatocytes.

Effects of the Japanese herbal medicine ‘Inchinko-to’ (TJ-135) on concanavalin A-induced hepatitis in mice

Inchinko-to (TJ-135) is a herbal medicine consisting of three kinds of crude drugs, and in Japan it is administered mainly to patients with cholestasis. The present study evaluated the effects of TJ-135 on concanavalin A (con A)-induced hepatitis in mice in vivo and con A-induced cytokine production in vitro. When mice were pretreated with oral TJ-135 for 1 week before intravenous con A injection, the activities of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) were significantly decreased 8 h after con A administration (-82%, -96% and -66% respectively). In histological investigations, sub-massive hepatic necrosis accompanying inflammatory cell infiltration was not observed in mice pretreated with TJ-135. Serum levels of interleukin-12 (IL-12), interferon-gamma (IFN-gamma) and IL-2 were significantly lower in mice pretreated with TJ-135 compared with controls, while IL-10 levels were higher in these mice. Intrasplenic IL-12 levels were significantly lower in mice pretreated with TJ-135, while intrasplenic IL-10 levels were higher in these mice. In vitro, IL-10 production by splenocytes was increased by the addition of TJ-135 to the culture medium, whereas the production of IL-12 and IFN-gamma was inhibited. These results suggest that con A-induced hepatitis was ameliorated by pretreatment with TJ-135. With regard to the mechanism of these effects of TJ-135, we speculate that TJ-135 inhibits the production of inflammatory cytokine and enhances the production of anti-inflammatory cytokines. Therefore administration of TJ-135 may be useful in patients with severe acute hepatitis accompanying cholestasis or in those with autoimmune hepatitis.

Effects of the Japanese herbal medicine ‘Inchinko-to’ (TJ-135) on concanavalin A-induced hepatitis in mice

Inchinko-to (TJ-135) is a herbal medicine consisting of three kinds of crude drugs, and in Japan it is administered mainly to patients with cholestasis. The present study evaluated the effects of TJ-135 on concanavalin A (con A)-induced hepatitis in mice in vivo and con A-induced cytokine production in vitro. When mice were pretreated with oral TJ-135 for 1 week before intravenous con A injection, the activities of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) were significantly decreased 8 h after con A administration (-82%, -96% and -66% respectively). In histological investigations, sub-massive hepatic necrosis accompanying inflammatory cell infiltration was not observed in mice pretreated with TJ-135. Serum levels of interleukin-12 (IL-12), interferon-γ (IFN-γ) and IL-2 were significantly lower in mice pretreated with TJ-135 compared with controls, while IL-10 levels were higher in these mice. Intrasplenic IL-12 levels were significantly lower in mice pretreated with TJ-135, while intrasplenic IL-10 levels were higher in these mice. In vitro, IL-10 production by splenocytes was increased by the addition of TJ-135 to the culture medium, whereas the production of IL-12 and IFN-γ was inhibited. These results suggest that con A-induced hepatitis was ameliorated by pretreatment with TJ-135. With regard to the mechanism of these effects of TJ-135, we speculate that TJ-135 inhibits the production of inflammatory cytokine and enhances the production of anti-inflammatory cytokines. Therefore administration of TJ-135 may be useful in patients with severe acute hepatitis accompanying cholestasis or in those with autoimmune hepatitis.

Macrophage inflammatory protein-2 (MIP-2) induced by TNF-a plays a pivotal role in concanavalin A-induced hepatitis in mice

Macrophage inflammatory protein-2 (MIP-2) induced by TNF-a plays a pivotal role in concanavalin A-induced hepatitis in mice

Sex differences of hepatic injury and cytokine production in concanavalin A-induced hepatitis in mice

Sex differences of hepatic injury and cytokine production in concanavalin A-induced hepatitis in mice

Protective effects of soyasapogenol A on liver injury mediated by immune response in a concanavalin A-induced hepatitis model

The present study was carried out to analyze the effects of soyasapogenol A on the liver injury mediated by the immune response in concanavalin A-induced hepatitis in mice. Soyasapogenol A reduced the number of infiltrating inflammatory cells in the liver and significantly lowered the elevated level of plasma tumor necrosis factor-α (TNF-α) 2 h after concanavalin A treatment, and then markedly reduced the elevated plasma alanine aminotransferase activity and decreased the number of apoptotic bodies in the liver parenchymal cells but not in the sinusoidal cells at 24 h. Since the effect of soyasapogenol A on the elevated plasma TNF-α level was not appreciable compared to the preventive effect of soyasapogenol A on the elevated plasma alanine aminotransferase level, these results suggest that soyasapogenol A directly prevents apoptosis of hepatocytes, and secondly, inhibits the elevation of plasma TNF-α, which consequently resulted in the prevention of liver damage in the concanavalin A-induced hepatitis model.

Galectin-1 exerts immunomodulatory and protective effects on concanavalin a-induced hepatitis in mice

Galectin-1, an endogenous lectin with immunomodulatory activities, induces selective, Fas-independent apoptosis of activated T cells. The aim of the present study was to evaluate the effect galectin-1 exerts on concanavalin A (Con A)-induced hepatitis, a T-cell-dependent model of liver injury. Con A administration resulted in liver injury, as shown by the increased transaminase plasma levels and liver DNA fragmentation, and caused spleen T-cell activation, which was associated with a strong increment in liver infiltrating T helper cells. Moreover, Con A injection leads to a marked increase in plasma tumor necrosis factor alpha (TNF-alpha) and interferon gamma (IFN-gamma) levels. Galectin-1 pretreatment dose-dependently prevented both liver injury and T-helper cell liver infiltration induced by Con A. In vivo and in vitro experiments indicated that the protective effects of galectin-1 depend on the selective elimination of Con A-activated T cells. In addition, galectin-1 almost completely prevented the Con A-induced increase in plasma TNF-alpha and IFN-gamma, an effect that was, at least in part, independent on the elimination of activated T helper cells, because galectin-1 prevented lipopolysaccharide (LPS)-induced release of TNF-alpha and IFN-gamma also from macrophages in vitro, without affecting their viability. The present study suggests that galectin-1 is potentially useful in the treatment of T-cell-mediated human liver disorders.

Sublobular veins as the main site of lymphocyte adhesion/transmigration and adhesion molecule expression in the porto-sinusoidal-hepatic venous system during concanavalin A-induced hepatitis in mice.

Lymphocyte infiltration is a manifest feature of hepatitis. To reveal the main site and mechanism of lymphocyte adhesion/extravasation in the hepatic vasculature during inflammation, we morphometrically and histologically analyzed these events in relation to adhesion molecule expression using a murine model of T-cell mediated hepatitis induced by concanavalin A (Con A). Although lymphocyte adhesion was restricted to the sinusoids in untreated mice, it increased in all the segments of porto-sinusoidal-hepatic venous system 8 hours after Con A injection; the number of adhering lymphocytes per unit vascular circumference was the largest in the sublobular veins, relatively large in the central veins and small hepatic veins, and relatively small in the sinusoids and negligible in the portal veins. At 20 hours, extravascular lymphocytes showed similar distribution to lymphocyte adhesion at 8 hours except in the portal veins, around which they were possibly accumulated by the translocation of extrasinusoidal lymphocytes. E-selectin and vascular cell adhesion molecule-1 (VCAM-1) were transiently expressed at 4 to 6 hours, whereas P-selectin and intercellular adhesion molecule-1 were not changed between 0 and 48 hours. In particular, E-selectin expression coincided with that of lymphocyte adhesion in distribution. Lymphocyte attachment was inhibited by pretreatment with anti-E-selectin monoclonal antibody (MAb) or anti-VCAM-1 MAb, and expression of E-selectin and VCAM-1 was suppressed by pretreatment with anti-tumor necrosis factor-alpha (TNF-alpha) MAb. Electron microscopically, lymphocytes were trapped by endothelial lamellipodia and traversed the endothelium by diapedesis. These results indicate that lymphocyte adhesion/transmigration preferentially takes place in the sublobular veins in association with TNF-alpha-induced endothelial activation, i.e., E-selectin and VCAM-1 expression and lamellipodia formation.

Bimodal role of endogenous interleukin-6 in concanavalin A-induced hepatitis in mice.

Acute concanavalin A (Con A)-induced hepatitis in mice is an animal model for hepatic injury induced by activated T cells. The evolution of hepatic involvement can be followed from hour to hour by measuring serum transaminase levels. We investigated the possible role of endogenous interleukin-6 (IL-6) in this model. We found serum IL-6 levels and splenic IL-6 mRNA during Con A-induced hepatitis to be significantly lower in interferon-gamma (IFN-gamma)-deficient mice, which are resistant against the Con A-induced syndrome, than in wild-type ones, suggesting that systemic IL-6 production favors development of hepatic injury. However, IL-6-deficient mice proved to be more susceptible to the disease than wild-type mice, indicating that endogenous IL-6 plays a predominantly hepatoprotective role. Experiments in which wild-type mice were treated with anti-IL-6 antibodies, before or after Con A challenge, allowed us to reconcile these contrasting observations. The antibody injections resulted in a biphasic alteration of serum IL-6 levels, initial neutralization being followed by rebound increased levels due to accumulation of IL-6 in the form of antigen-antibody complexes. The effect of antibody on disease severity differed depending on the time of injection. Antibody injection at 2.5 h post Con A resulted in delayed disease manifestation, whereas treatment initiated before Con A resulted in accelerated disease. We conclude that endogenous IL-6 plays a bimodal role. IL-6 present before Con A challenge as well as that induced in the very early phase after Con A injection triggers hepatoprotective pathways. Continuation of IL-6 production beyond this early phase, by some other pathway, seems to be harmful to hepatocytes.

Treatment of concanavalin A-induced hepatitis in mice with low molecular weight heparin

Background/Aims: Heparin has been noted to inhibit inflammation independent of its known anti-coagulant activity. In the present study, we examined the ability of heparin and low molecular weight heparin to prevent immune-mediated, concanavalin A-induced liver damage. Methods: Mice were pretreated with either heparin or low molecular weight heparin (Fragmin) prior to their inoculation with concanavalin A (10 mg/kg). Liver enzymes, liver histology, and the serum levels of tumor necrosis factor- a, interleukin-6, and interleukin-10 were examined in the control and treated mice. Results: The histopathologic damage in the liver, and the concanavalin A-induced release of aminotransferases, tumor necrosis factor- a, and interleukin-6 were significantly inhibited in mice pretreated with low molecular weight heparin, whereas the serum levels of the anti-inflammatory cytokine interleukin-10 were increased ( p<0.01). Interestingly, maximal inhibition was obtained with low low molecular weight heparin doses (5 and 1 μg/mouse, p<0.001), while higher doses were less effective. Concanavalin A-induced liver injury was not prevented by pretreatment of the mice with heparan sulphate ( p<0.001), which although it is structurally similar to heparin possesses neither anti-inflammatory nor anti-coagulant properties. Conclusions: This study demonstrates the efficacy of low molecular weight heparin in preventing immunemediated liver damage in mice.

Concanavalin A-induced Hepatitis in Mice is Prevented by Interleukin (IL)-10 and Exacerbated by Endogenous IL-10 Deficiency

One single intra-venous (i.v.) injection of Concanavalin A (Con A) into mice provokes a cell-mediated immunoinflammatory hepatitis. We have presently evaluated the immunopharma-cological effects of exogenous interleukin (IL)-10 and the role of endogenous IL-10 in this model by using exogenous IL-10, anti-IL-10 monoclonal antibody (mAb) and mice with disrupted IL-10 gene (IL-10 KO mice). Whilst exogenous IL-10 administered in a prophylactic (lh prior to Con A) and even “early” therapeutic fashion (30min after Con A) reduced the elevation of transaminase activities in plasma in a dose-dependent manner, observed in control mice, these biochemical markers of liver injury were significantly increased both in IL-10 KO mice as well as in those receiving anti-IL-10 mAb. Interestingly, doses of Con A lower than 20 mg/kg that were only capable of inducing slight serological signs of hepatitis in mice, exerted marked hepatitic effects when administered to either anti-IL-10 mAb-treated mice or to IL-10 KO mice. The disease modulating effects of exogenous IL-10 and either genetical or pharmacologically-induced IL-10 deficiency were associated with profound and opposite modifications of the Con A-induced increase in the circulating levels of IFN-y and TNF-a. Relative to control animals, the blood levels of these cytokines were diminished in IL-10-treated mice and augmented in both IL-10 KO mice and anti-IL-10 mAb-treated mice. These results prove the physiological antiinflammatory role of endogenous IL-10 in Con A induced hepatitis and the beneficial effects of IL-10 treatment to prevent this condition.

Production and role of interleukin-10 in concanavalin A-induced hepatitis in mice.

Experimental T-cell-mediated hepatitis induced by concanavalin A (Con A) involves the production of proinflammatory cytokines. Because interleukin (IL)-10 is a potent anti-inflammatory cytokine derived from macrophages and T cells and is produced within the liver, we investigated the role of IL-10 in modulating the hepatotoxicity and the secretion of cytokines following in vivo injection of Con A. IL-10 is produced early in the serum after Con A challenge. Neutralization of endogenous IL-10 by monoclonal antibodies (mAbs) increases the secretion of tumor necrosis factor alpha (TNF-alpha) (+111%), interferon gamma (IFN-gamma) (+92%), and IL-12 (+730%) 8 hours after Con A injection, and increases the hepatotoxicity, assessed by serum alanine transaminase (ALT) (+174%) measurement and by histology, 24 hours after induction of hepatitis. Conversely, preadministration of recombinant IL-10 reduces the production of these proinflammatory cytokines (-47%, -80%, and -47% for TNF-alpha, IL-12, and IFN-gamma, respectively), and decreases neutrophil infiltration and ALT serum concentration (-74%) 8 hours after Con A challenge. We conclude that IL-10, either endogenously produced or exogenously added, has a hepatoprotective role in Con A-induced hepatitis, through its suppressive property on proinflammatory cytokine production, and that it might be of therapeutic relevance in human liver diseases involving activated T cells.

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A previous study demonstrated that Fumigaclavine C (FC) had a potential immunosuppressive activity against concanavalin A-induced hepatitis in mice. However, the precise mechanisms of the anti-inflammatory and hepatoprotective effects of FC are incompletely delineated. This study further investigated the protective effects of FC on lipopolysaccharide (LPS)-induced murine RAW264.7 cells and the underlying molecular mechanism in liver kupffer cells. FC differentially attenuated the production of tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β), interleukin-6 (IL-6), interferon gamma (IFN-γ), and high mobility group box protein 1 (HMGB-1). Intriguingly, FC significantly suppressed LPS-induced HMGB-1 nucleo-cytoplasmic shuttling relocation and release. FC notably decreased the phosphorylation levels of phosphatidylinositol 3-kinase (PI3K), phosphoinositide-dependent kinase 1 (PDK1), protein kinase C beta II (PKCβII), and protein kinase C gamma (PKCγ). PKCβII/γ played an important part in this signaling pathway cascade. Furthermore, the docking simulation revealed that FC could directly bind to the HMGB-1 B box interfering with Lys90 and Leu145. All of these results indicated that FC exhibited anti-inflammatory and hepatoprotective effects through suppressing HMGB-1 relocation and release by interfering with Lys90 and Leu145.