ConA-induced Acute Liver Injury Research Articles

Concanavalin-A-Induced Acute Liver Injury in Mice.

Acute liver injury is a life-threatening disease. Although immune responses are involved in the development and exacerbation of acute liver injury, the cellular and molecular mechanisms are not fully understood. Intravenous administration of the plant lectin concanavalin A (ConA) is widely used as a model of acute liver injury. ConA triggers T cell activation and cytokine production by crosslinking glycoproteins, including the T cell receptor, leading to the infiltration of myeloid cells into the liver and the subsequent amplification of inflammation in the liver. Thus, the pathogenesis of ConA-induced acute liver injury is considered a model of immune-mediated acute liver injury or autoimmune hepatitis in humans. However, the severity of the liver injury and the analyses of immune cells and non-hematopoietic cells in the liver following ConA injection are significantly influenced by the experimental conditions. This article outlines protocols for ConA-induced acute liver injury in mice and evaluation methods for liver injury, immune cells, and non-hematopoietic cells in the liver. © 2024 Wiley Periodicals LLC. Basic Protocol 1: Induction of acute liver injury by ConA injection Basic Protocol 2: Evaluation of inflammatory cytokines in mouse plasma Basic Protocol 3: Preparation of liver sections and histological analysis of liver injury Basic Protocol 4: Preparation of liver immune cells Basic Protocol 5: Preparation of hepatocytes, endothelial cells, and hepatic stellate cells Basic Protocol 6: Flow cytometry of immune and non-hematopoietic liver cells Basic Protocol 7: Flow cytometric sorting of endothelial cells and hepatic stellate cells Basic Protocol 8: Quantitative reverse transcription polymerase chain reaction.

Interleukin 28A aggravates Con A-induced acute liver injury by promoting the recruitment of M1 macrophages.

Immune-mediated acute hepatic injury is characterized by the destruction of a large number of hepatocytes and severe liver function damage. Interleukin-28A (IL-28A), a member of the IL-10 family, is notable for its antiviral properties. However, despite advances in our understanding of IL-28A, its role in immune-mediated acute injury remains unclear. The present study investigated the role of IL-28A in concanavalin A (Con A)-induced acute immune liver injury. After Con A injection in mice, IL-28A level significantly increased. IL-28A deficiency was found to protect mice from acute liver injury, prolong survival time, and reduce serum aspartate aminotransferase and alanine aminotransferase levels. In contrast, recombinant IL-28A aggravated liver injury in mice. The proportion of activated M1 macrophages was significantly lower in the IL-28A-deficiency group than in the wild-type mouse group. In adoptive transfer experiments, M1 macrophages from WT could exacerbate mice acute liver injury symptoms in the IL-28A deficiency group. Furthermore, the expression of proinflammatory cytokines, including tumor necrosis factor-α (TNF-α), IL-12, IL-6, and IL-1β, by M1 macrophages decreased significantly in the IL-28A-deficiency group. Western blotting demonstrated that IL-28A deficiency could limit M1 macrophage polarization by modulating the nuclear factor (NF)-κB, mitogen-activated protein kinase (MAPK), and interferon regulatory factor (IRF) signaling pathways. In summary, IL-28A deletion plays an important protective role in the Con A-induced acute liver injury model and IL-28A deficiency inhibits the activation of M1 macrophages by inhibiting the NF-κB, MAPK, and IRF signaling pathways. These results provide a potential new target for the treatment of immune-related hepatic injury.

DNAM-1 Immunoreceptor Protects Mice from Concanavalin A-Induced Acute Liver Injury by Reducing Neutrophil Infiltration.

DNAX accessory molecule-1 (DNAM-1; CD226) is an activating immunoreceptor on T cells and NK cells. The interaction of DNAM-1 with its ligand CD155 expressed on hematopoietic and nonhematopoietic cells plays an important role in innate and adaptive immune responses. In this study, we investigated the role of the DNAM-1-CD155 axis in the pathogenesis of T cell-mediated Con A-induced acute liver injury. Unexpectedly, DNAM-1-deficient (Cd226-/-) mice exhibited more severe acute liver injury and higher concentrations of IL-6 and TNF-α than did wild-type (WT) mice after Con A injection. We found that a larger number of neutrophils infiltrated into the liver of Cd226-/- mice compared with WT mice after Con A injection. Depletion of neutrophils ameliorated liver injury and decreased IL-6 and TNF-α in Cd226-/- mice after Con A injection, suggesting that neutrophils exacerbate the liver injury in Cd226-/- mice. Hepatocytes produced more significant amounts of CXCL1, a chemoattractant for neutrophils, in Cd226-/- mice than in WT mice after Con A injection. In the coculture of hepatocytes with liver lymphocytes, either DNAM-1 deficiency in liver lymphocytes or CD155 deficiency in hepatocytes promoted CXCL1 production by hepatocytes. These results suggest that the interaction of DNAM-1 with CD155 inhibits CXCL1 production by hepatocytes, leading to ameliorating acute liver injury.

Circadian control of ConA-induced acute liver injury and inflammatory response via Bmal1 regulation of Junb

Circadian rhythms play significant roles in immune responses, and many inflammatory processes in liver diseases are associated with malfunctioning molecular clocks. However, the significance of the circadian clock in autoimmune hepatitis (AIH), which is characterised by immune-mediated hepatocyte destruction and extensive inflammatory cytokine production, remains unclear. We tested the difference in susceptibility to the immune-mediated liver injury induced by concanavalin A (ConA) at various time points throughout a day in mice and analysed the effects of global, hepatocyte, or myeloid cell deletion of the core clock gene, Bmal1 (basic helix-loop-helix ARNT-like 1), on liver injury and inflammatory responses. Multiple molecular biology techniques and mice with macrophage-specific knockdown of Junb, a Bmal1 target gene, were used to investigate the involvement of Junb in the circadian control of ConA-induced hepatitis. The susceptibility to ConA-induced liver injury is highly dependent on the timing of ConA injection. The treatment at Zeitgeber time 0 (lights on) triggers the highest mortality as well as the severest liver injury and inflammatory responses. Further study revealed that this timing effect was driven by macrophage, but not hepatocyte, Bmal1. Mechanistically, Bmal1 controls the diurnal variation of ConA-induced hepatitis by directly regulating the circadian transcription of Junb and promoting M1 macrophage activation. Inhibition of Junb in macrophages blunts the administration time-dependent effect of ConA and attenuates liver injury. Moreover, we demonstrated that Junb promotes macrophage inflammation by regulating AKT and extracellular signal-regulated kinase (ERK) signalling pathways. Our findings uncover a critical role of the Bmal1-Junb-AKT/ERK axis in the circadian control of ConA-induced hepatitis and provide new insights into the prevention and treatment of AIH. This study unveils a critical role of the Bmal1-Junb-AKT/ERK axis in the circadian control of ConA-induced liver injury, providing new insights into the prevention and treatment of immune-mediated hepatitis, including autoimmune hepatitis (AIH). The findings have scientific implications as they enhance our understanding of the circadian regulation of immune responses in liver diseases. Furthermore, clinically, this research offers opportunities for optimising treatment strategies in immune-mediated hepatitis by considering the timing of therapeutic interventions.

Deletion of Cyclic GMP-AMP Synthase Aggravates Concanavalin A-Induced Acute Hepatic Injury by Facilitating Leukocyte Chemotaxis

Growing evidence demonstrates that cyclic GMP-AMP synthase (cGAS), as a cytosolic DNA sensor, is essential for activating innate immunity and regulating inflammatory response against cellular damage. However, its role in immune-mediated hepatitis remains unclear. Here by challenging the cGAS knockout (KO) and their littermate wide-type (WT) mice with intravenous ConA injection to induce acute immune-mediated liver injury, we found that lack of cGAS drastically aggravated liver damage post ConA treatment for 24h, reflected by increased alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels and amplified hepatic necrosis. The number of apoptotic hepatocytes was also significantly increased in the KO mice. RNA-sequencing analysis revealed that leukocyte chemotaxis and migration-related genes were remarkably upregulated in the KO livers. Consistently, immunofluorescence assays illustrated that the infiltrating F4/80-positive macrophages, Ly6G-positive neutrophils, and CD3-positive T cells were all significantly increased in the KO liver sections. The hepatic expression of the pro-inflammatory genes was elevated as well. Supporting the in vivo findings, the knockdown of cGAS in cultured macrophages showed promoted migration potential and enhanced pro-inflammatory gene expression. These results collectively demonstrated that deletion of cGAS could aggravate ConA-induced acute liver injury, at least at the 24-h time point, and its mechanism might be related to facilitating leukocyte chemotaxis and promoting liver inflammatory response.

A Synbiotic Ameliorates Con A-Induced Autoimmune Hepatitis in Mice through Modulation of Gut Microbiota and Immune Imbalance.

Changes in the intestinal flora are related to autoimmune hepatitis (AIH) development. The aim of this study is to investigate the synergistic effects of probiotics and prebiotics on liver injury induced by concanavalin A (Con A). C57BL/6 mice are fed probiotics (Pro), prebiotics (Pre), synbiotic (Syn) for 7 days and then Con A is injected via tail veins to induce AIH. Additionally, methylprednisolone (MP) is gavaged 0.5h after the Con A injection. It is found that both Pro, Pre, Syn, and MP decrease the levels of serum transaminase, liver F4/80+ macrophage cells, and hepatocellular apoptosis. Pro, Pre, and Syn decrease proinflammatory cytokines, elevate levels of anti-inflammatory as well as restored immune imbalance in AIH. Besides, Pro, Pre, and Syn not only reshape the perturbed gut microbiota, but also maintain intestinal barrier integrity, block the activation of lipopolysaccharide (LPS)/TLR4/NF-κB pathway in the liver. Interestingly, the effects of Syn are superior to Pro or Pre alone in Con A-induced acute liver injury. Syn obviously facilitates AIH remission. The combined use of Pro and Pre is effective in improving Pro and Pre efficacy and can be an important tool for preventing and adjuvant treating patients for AIH.

Molecular mechanism of anti-inflammatory effects of the proteasome inhibitor MG-132 on Con A-induced acute liver injury in mice

MG-132, an aldehyde-based peptide proteasome inhibitor (PI) that binds to the proteasome and reversibly inhibits proteasome activity, has been widely used in experimental research. However, it is not clear whether MG-132 has anti-inflammatory effects on liver injury. The molecular mechanism of the anti-inflammatory effect of the PI MG-132 on Con A-induced acute liver injury (ALI) mice was investigated by ELISA, HE, q RT-PCR, and IHC. The results showed that the serum activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and TNF-α and IL-6 contents of mice in the high and medium dose groups were reduced compared with those in the ALI group. The superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels in liver tissues were significantly increased, and the malondialdehyde (MDA) content was decreased. The pathological sections of mice in the ALI group showed typical ALI manifestations such as significant central venous stasis of liver tissues, cell swelling, and inflammatory cell infiltration. The pathological damage of liver tissues was relieved significantly in the three dose groups, especially in the high-dose group. The transcriptional level of TLR4/NF-κB pathway key factors mRNA was significantly reduced, and the expression of TLR4 and NF-κB P65 protein in liver tissues was significantly and positively correlated with the contents of TNF-α and IL-1β (p < 0.01). Our findings suggest that MG-132 can alleviate the inflammatory response to Con A-induced ALI and exert a hepatoprotective effect, and its anti-inflammatory effect is related to the inhibition of TLR4/NF-κB signaling pathway activation.

Tivantinib alleviates inflammatory diseases by directly targeting NLRP3

NLRP3 inflammasome-mediated immune responses are involved in the pathogenesis of multiple inflammatory diseases, but few clinical drugs are identified that directly target the NLRP3 inflammasome to treat these diseases to date. Here, we show that the anticancer agent tivantinib is a selective inhibitor of NLRP3 and has a strong therapeutic effect on inflammasome-driven disease. Tivantinib specifically inhibits canonical and non-canonical NLRP3 inflammasome activation without affecting AIM2 and NLRC4 inflammasome activation. Mechanistically, Tivantinib inhibits NLRP3 inflammasome by directly blocking NLRP3 ATPase activity and subsequent inflammasome complex assembly. Invivo, Tivantinib reduces IL-1β production in mouse models of lipopolysaccharide (LPS)-induced systemic inflammation, monosodium urate (MSU)-induced peritonitis and Con A-induced acute liver injury (ALI), and also has remarkable preventive and therapeutic effects on experimental autoimmune encephalomyelitis (EAE). In conclusion, our study identifies the anticancer drug tivantinib as a specific inhibitor of NLRP3 and provides a promising therapeutic agent for inflammasome-driven disease.

The molecular mechanism of acute liver injury and inflammatory response induced by Concanavalin A

Acute liver injury is a common but urgent clinical condition, and its underlying mechanism remains to be further elucidated. Concanavalin A (ConA)-induced liver injury was investigated in the study. Different from the caspase-dependent cell apoptosis in lipopolysaccharide/D-aminogalactose (LPS/D-GalN) induced liver injury, ConA-induced hepatocyte death was independent on caspase. Increased hepatocytic expressions of mixed lineage kinase domain like (MLKL) and receptor-interacting protein kinase 1 (RIPK1), and higher serum concentration of tumor necrosis factor-α (TNF-α) were noticed in mice with ConA-induced liver injury. Inhibition of RIPK1 protein or deletion of MLKL gene could significantly attenuate the acute liver injury and improve mice survival. Besides, the ConA treatment induced severe hepatic inflammation in wide type (WT) mice in comparison with Mlkl−/− mice, suggesting the RIPK1-MLKL-mediated hepatocellular necroptosis might participate in the process of liver injury. Moreover, mitochondrial damage associated molecular patterns (DAMPs) were subsequently released after the hepatocyte death, and further activated the p38 mitogen-activated protein kinase (MAPK) pathway, which could be reduced by deletion or inhibition of Toll-like receptor 9 (TLR9). Taken together, our research revealed that ConA-induced acute liver injury was closely related to TNF-α-mediated cell necroptosis, and inhibiting RIPK1 or deleting MLKL gene could alleviate liver injury in mice. The mitochondrial DNA released by dead hepatocytes further activated neutrophils through TLR9, thus resulting in the exacerbation of liver injury.

Diallyl trisulfide protects against concanavalin A-induced acute liver injury in mice by inhibiting inflammation, oxidative stress and apoptosis

AimsTo investigate the protective effects and underlying mechanisms of diallyl trisulfide (DATS) against acute liver injury induced by concanavalin A (Con A). Materials and methodsDATS (20, 40, 80 mg/kg) were gavaged to ICR mice 1 h before Con A (20 mg/kg) tail vein injection. The survival rate of mice, alterations of serum biochemical markers and liver histopathology were measured to evaluate the protective effects of DATS at 24 h after Con A exposure. The indexes of inflammation, oxidative stress and apoptosis were determined to explore the possible mechanisms. Key findingsDATS pretreatment increased survival rate of mice in a dose-dependent manner, inhibited the increase of liver-to-spleen ratio and serum liver injury markers, and attenuated liver pathological damage induced by Con A. Further study showed that DATS pretreatment inhibited the activation of Kupffer cells/macrophages, release of tumor necrosis factor-α (TNF-α) and Caspase-1-dependent inflammation induced by Con A. Moreover, DATS pretreatment alleviated the oxidative stress induced by Con A, which was evidenced by increased superoxide dismutase (SOD) and catalase (CAT) activities and decreased malondialdehyde (MDA) content in DATS and Con A co-treated mice compared with Con A alone group. Finally, DATS pretreatment reduced eosinophilic body formation, TUNEL positive staining and increased Bcl-2/Bax ratio in liver of Con A-injected mice, indicating attenuated apoptosis. SignificanceCollectively, the results suggest that DATS displays potent protective effects against Con A-induced acute liver injury in mice possibly through inhibition of inflammation, oxidative stress and apoptosis.

Hepatocyte-Derived Igκ Exerts a Protective Effect against ConA-Induced Acute Liver Injury.

Immunoglobulin (Igκ) has been reported to be expressed in sorted liver epithelial cells of μMT mice, and the sequence characteristics of hepatocyte-derived Igκ were different from those of classical B-cell-derived Igκ. However, the physiological function of hepatocyte-derived Igκ is still unclear. The expression of Igκ was firstly identified in primary hepatocytes and normal liver cell line (NCTC1469), and hepatocyte-derived Igκ expression was elevated and displayed unique localization in hepatocytes of concanavalin A (ConA)-induced hepatitis model. Moreover, Igκ knockout mice were more sensitive to ConA-induced hepatitis and had higher serum aspartate aminotransferase (AST) levels, more severe histological injury and a greater number of terminal deoxynucleotide transferase-mediated deoxyuridine triphosphate nick end-labeling (TUNEL)-positive cells as compared with littermate controls. Furthermore, knockdown of Igκ in primary hepatocytes and NCTC1469 cells led to accelerated activation of the mitochondrial death pathway and caspase-3 cleavage in vitro, which might be related to inhibition of NF-κB signaling pathway and activation of JNK via the cytoskeleton dynamics. Taken together, these results indicate that hepatocyte-derived Igκ mediates cellular resistance to ConA-induced liver injury by inhibiting activation of caspase-3 and the mitochondrial death pathway, suggesting that Igκ plays an important role in hepatocyte survival and exerts a protective effect against ConA-induced liver injury in mice.

Amphiregulin alleviated concanavalin A-induced acute liver injury via IL-22

Objectives Amphiregulin (Areg), a glycoprotein from the epidermal growth factor receptor (EGFR) ligand family, has a well-documented protective role against tissue injury; however, its effects on immune-mediated liver injury are still unclear. Here, we used a concanavalin A (ConA)-induced acute liver hepatitis model to explore the effects of Areg on immune-mediated acute liver injury. Materials and methods Some C57BL/6 mice were administered ConA at a dose of 20 mg/kg (model mice), and some received 5 µg of Areg (treated mice). Then, their survival rates over 36 h were analyzed. After 5 h of treatment, liver function, hepatic histology, and apoptosis in liver tissue were investigated, and cytokine expression and neutrophil infiltration and activity in the liver were detected. Moreover, the protective effects of Areg were also evaluated without IL-22 in vivo. Results Our results showed that Areg administration increased acute liver failure (ALF) mouse survival, restored liver function, and alleviated liver damage. Interestingly, Areg administration increased IL-22 production in hepatic T cells and upregulated IL-22 concentrations in the serum and liver, whereas IL-22 neutralization completely abolished the therapeutic effect of Areg. Meanwhile, Areg administration was concomitant with increased expression of the anti-apoptotic proteins Bcl-2 and Bcl-xL, which are important in the hepatoprotective mechanism of IL-22. Conclusions Areg showed direct protective effects against ConA-induced acute liver injury, which suggests the potential therapeutic application of Areg in immune-mediated ALF.

Mycophenolate mofetil attenuates concanavalin A-induced acute liver injury through modulation of TLR4/NF-κB and Nrf2/HO-1 pathways.

Acute liver injury (ALI) is a serious health condition associated with rising morbidity and sudden progression. This study was designed to investigate the possible hepatocurative potential of two dose levels (30 and 60mg/kg) of Mycophenolate mofetil (MMF), an immune-suppressant agent, against Concanavalin A (Con A)-induced ALI in mice. A single dose of Con A (20mg/kg, IV) was used to induce ALI in mice. MMF (30mg/kg and 60mg/kg) was administered orally for 4days post Con A injection. MMF (30mg/kg) failed to cause significant amelioration in Con A-induced ALI while MMF (60mg/kg) significantly alleviated Con A-induced ALI. Administration of MMF (60mg/kg) significantly decreased Con A-induced increase in serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels. Additionally, MMF significantly restored the disrupted oxidant/antioxidants status induced by Con A. MMF caused marked increase in hepatic nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) levels. Moreover, MMF significantly reduced Con A-induced increase in the expression of hepatic toll-like receptor 4 (TLR4), nuclear factor kappa-B (NF-κB), tumor necrosis factor-α (TNF-α), interferon-γ (INF-γ) and interleukin-1β (Il-1β). Also, MMF administration significantly decreased Con A-induced increase in the immune-expression of pro-apoptotic Bcl-2-associated X protein (Bax) and markedly increased Con A-induced decrease in the anti-apoptotic B-cell lymphoma 2 protein (Bcl2). The observed ameliorative effect of MMF against Con A-induce ALI may be contributed to its anti-inflammatory, anti-oxidant and anti-apoptotic potentials taking into consideration that TLR4/NF-κB and Nrf2/HO-1 are the main implicated pathways. Schematic diagram summarizing the possible mechanisms underlying the ameliorative potential of Mycophenolate Mofetil against Con A-induced acute liver injury. Bax Bcl-2-associated X protein, Bcl2 B-cell lymphoma 2, MMF Mycophenolate mofetil, Con A Concanavalin A, GSH reduced glutathione, HO-1 Heme oxygenase-1, IL-1β Interleukin-1β, IFN-γ Interferon-γ, MDA Malondialdehyde, NF-κB Nuclear Factor Kappa B, Nrf2 Nuclear factor erythroid 2-related factor 2, NO Nitric Oxide, SOD Superoxide Dismutase, TLR4 Toll-like receptor 4, TNF-α tumor necrosis factor-α.

Maresin 1 mitigates concanavalin A-induced acute liver injury in mice by inhibiting ROS-mediated activation of NF-κB signaling

The liver is the most important metabolic and detoxifying organ in the human body, and liver damage can seriously affect bodily function and potentially be life threatening. Accumulating evidence suggests that maresin 1 (MaR1) exhibits protective and anti-inflammatory effects in some diseases, such as pneumonia and colitis; however, its role in acute hepatitis remains unclear. Here, we established a concanavalin A (ConA)-induced acute liver-injury mouse model to determine whether MaR1 administration can attenuate liver damage. Our results indicate that MaR1 confers protective effects against ConA-induced acute liver injury, improves liver function and survival, and reduces histopathological damage. Additionally, MaR1 attenuated the inflammatory response and reduced hepatocyte apoptosis while increasing mouse macrophage apoptosis and markedly decreasing levels of reactive oxygen species (ROS) in macrophages. We also found that MaR1 significantly inhibited ConA-induced activation of the nuclear factor-kappaB (NF-κB) pathway. This work will contribute to a better understanding of acute liver injury (ALI) and advancement towards its treatment.

The Protective Effect of Aesculus hippocastanum (Venoplant®) Against Concanavalin A-Induced Liver Injury

Aim: The present study was performed to investigate the effect of Aesculus hippocastanum (AH; Venoplant®) on concanavalin A (ConA)-induced acute liver injury and explore the mechanism in mice. Methods: ConA (20 mg/kg) was administered via tail vein injection to induce hepatic damage. The groups of AH (Venoplant®) were given at 65.8, 131.6, and 263.2 mg/kg by oral gavages for 20 days. The serum levels of aspartate transaminase (AST), alanine aminotransferase (ALT), total protein (TP), and albumin (Alb) were determined by automatic biochemical analyzer, and the Alb/globulin (A/G) ratio was calculated. Tumor necrosis factor-α (TNF-α) and IFN-γ levels were assayed by enzyme-linked immunosorbent assay. The liver tissue was attained by hematoxylin and eosin, and the histopathological changes were calculated. The cell apoptosis was assayed by terminal dUTP nick-end labeling. The malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione (GSH) content of liver tissue were assayed by related kits. The activity of caspase-3 was detected by spectrophotometry. The expressions of cytochrome c, Bax, Bcl-2, c-Jun N-terminal kinase (JNK), and p-JNK were detected by western blot. Results: The results showed that the levels of ALT, AST, IFN-γ, and TNF-α in AH (Venoplant®) groups were significantly lower than those in ConA-injured group, while the levels of TP, Alb, and A/G were significantly higher. The SOD and GSH levels were significantly increased, and the MDA level was decreased; liver histopathology was changed consistently with the serological indicators, AH (Venoplant®) treatment significantly reduced the pathological damage and cell apoptosis; while in AH (Venoplant®) group, the expressions of cytochrome c, caspase-3, Bax/Bcl-2 ratio, and p-JNK were significantly decreased. Conclusion: AH (Venoplant®) could significantly protect the ConA-induced acute liver injury in mice via inhibition of reactive oxygen species and JNK pathway.

Hepatoprotective activity of isostrictiniin from Nymphaea candida on Con A-induced acute liver injury in mice

This study is to investigate hepatoprotective activity of isostrictiniin from Nymphaea candida. Hepatic injury in mice was induced immunologically by caudal vein injecting Con A (20 mg/kg) on tenth day of isostrictiniin (25, 50, or 100 mg/kg) intragastric administration. The results demonstrated that pretreatment with isostrictiniin significantly and dose-dependently prevented increase of serum AST and ALT induced by Con A (P < 0.05). Isostrictiniin significantly reduced the levels of MDA and NO in the liver tissue and restored activities of antioxidant enzymes SOD and GSH compared with model group (P < 0.05). Furthermore, the increase of pro-inflammatory cytokines TNF-α, IL-1β, IL-6 and IL-18 levels were significantly suppressed by isostrictiniin pretreatment compared with model group (P < 0.05). Histopathological analysis showed that isostrictiniin attenuated the hepatocellular necrosis and reduction of inflammatory cells infiltration. The results indicates that preventive effect of isostrictiniin on acute liver injury may be attributed to its antioxidative and immunomodulatory activities.

Protective effects of specific cannabinoid receptor 2 agonist GW405833 on concanavalin A-induced acute liver injury in mice.

Cannabinoid receptor 2 (CB2R) is highly expressed in immune cells and plays an important role in regulating immune responses. In the current study, we investigated the effects of GW405833 (GW), a specific CB2R agonist, on acute liver injury induced by concanavalin A (Con A). In animal experiments, acute liver injury was induced in mice by injection of Con A (20 mg/kg, i.v.). The mice were treated with GW (20 mg/kg, i.p., 30 min after Con A injection) or GW plus the selective CB2R antagonist AM630 (2 mg/kg, i.p., 15 min after Con A injection). We found that Con A caused severe acute liver injury evidenced by significantly increased serum aminotransferase levels, massive hepatocyte apoptosis, and necrosis, as well as lymphocyte infiltration in liver tissues. Treatment with GW significantly ameliorated Con A-induced pathological injury in liver tissue, decreased serum aminotransferase levels, and decreased hepatocyte apoptosis. The therapeutic effects of GW were prevented by AM630. In cell experiments, we showed that CB2Rs were highly expressed in Jurkat T cells, but little expression in L02 liver cells. Treatment with GW (10-40 μg/mL) dose-dependently decreased the viability of Jurkat T cells and induced cell apoptosis, which was reversed by AM630. In the coculture of Jurkat T cells with L02 liver cells, GW dose-dependently protected L02 cells from apoptosis induced by Con A (5 μg/mL). The protective effect of GW was reversed by AM630 (1 μg/mL). Our results suggest that GW protects against Con A-induced acute liver injury in mice by inhibiting Jurkat T-cell proliferation through the CB2Rs.

Human liver stem cells attenuate concanavalin A-induced acute liver injury by modulating myeloid-derived suppressor cells and CD4+ T cells in mice

BackgroundAcute liver failure (ALF) is a serious threat to the life of people all over the world. Finding an effective way to manage ALF is important. Human liver stem cells (HLSCs) are early undifferentiated cells that have been implicated in the regeneration and functional reconstruction of the liver. In this study, we aimed to evaluate the protective effects of the HLSC line HYX1 against concanavalin A (ConA)-induced acute liver injury.MethodsHYX1 cells were characterized by microscopy, functional assays, gene expression, and western blot analyses. We showed that HYX1 cells can differentiate into hepatocytes. We intraperitoneally injected HYX1 cells in mice and administered ConA via caudal vein injection 3, 6, 12, 24, and 48 h later. The effects of HYX1 cell transplantation were evaluated through blood tests, histology, and flow cytometry.ResultsHYX1 cells reduced the levels of alanine transaminase (ALT), aspartate aminotransferase (AST), and total bilirubin (TBIL) in serum and dramatically decreased the severity of liver injuries. Mechanistically, HYX1 cells promoted myeloid-derived suppressor cell (MDSC) migration into the spleen and liver, while reducing CD4+ T cell levels in both tissues. In addition, HYX1 cells suppressed the secretion of proinflammatory cytokines, such as tumour necrosis factor-α (TNF-α) and interferon-γ (IFN-γ), but led to increased interleukin-10 (IL-10) production.ConclusionsThese results confirm the efficacy of HLSCs in the prevention of the ConA-induced acute liver injury through modulation of MDSCs and CD4+ T cell migration and cytokine secretion.

The Hepatoprotection by Oleanolic Acid Preconditioning: Focusing on PPARα Activation.

Objective Previous studies have characterized the hepatoprotective and anti-inflammatory properties of oleanolic acid (OA). This study aimed to investigate the molecular mechanisms of OA hepatoprotection in concanavalin A- (ConA-) induced acute liver injury. Materials and Methods ConA (20 mg/kg) was intravenously injected to induce acute liver injury in Balb/C mice. OA pretreatment (20, 40, and 80 mg/kg) was administered subcutaneously once daily for 3 consecutive days prior to treatment with ConA; 2, 8, and 24 h after ConA injection, the levels of serum liver enzymes and the histopathology of major factors and inflammatory cytokines were determined. Results OA reduced the release of serum liver enzymes and inflammatory factors and prevented ConA mediated damage to the liver. OA elevated the expression levels of peroxisome proliferator-activated receptor alpha (PPARα) and decreased the phosphorylation of c-Jun NH2-terminal kinase (JNK). Conclusion OA exhibits anti-inflammatory properties during ConA-induced acute liver injury by attenuating apoptosis and autophagy through activation of PPARα and downregulation of JNK signaling.

Protective effect of intraperitoneal transplantation of human liver-derived stem cells at different times against concanavalin A-induced acute liver injury in mice

Objective: To investigate the protective effect of intraperitoneal transplantation of human liver-derived stem cells at different times against concanavalin A (ConA)-induced acute liver injury in mice. Methods: A total of 88 male C57BL/6 mice were randomly divided into normal control group (group C), ConA model group (group M), and human liver-derived stem cells (HYX1)+ConA group (group E); according to the interval between phosphate buffer/HYX1 injection and ConA injection, Groups M and E were further divided into 3-hour groups (M1 and E1 groups), 6-hour groups (M2 and E2 groups), 12-hour groups (M3 and E3 groups), 24-hour groups (M4 and E4 groups), and 48-hour groups (M5 and E5 groups). The levels of alanine aminotransferase (ALT), aspartate transaminase (AST), and total bilirubin (TBil) in peripheral blood were measured, liver tissue sections were used to observe pathological changes, and the Ishak score for liver inflammation was determined. The independent samples t-test was used for comparison between groups, and P < 0.05 was considered statistically significant. Results: The levels of ALT, AST, and TBil in group C were (36.25±1.16) U/L, (120.20±5.77) U/L, and (2.20±0.23) μmol/L, respectively; the levels of ALT, AST, and TBil and Ishak score were (8 721.23±837.39) U/L, (8 110.31±290.10) U/L, (8.41±0.10) μmol/L, and (13.32±1.30), respectively, in group M1, (8 334.31±666.50) U/L, (7 560.20±760.34) U/L, (10.40±0.80) μmol/L, and (12.67±0.81), respectively, in group M2, (8 960.75±551.93) U/L, (8 535.62±675.14) U/L, (10.95±1.43) μmol/L, and (14.57±0.65), respectively, in group M3, (8 618.57±886.40) U/L, (11 440.54 ± 1 327.86) U/L, (13.30±1.86) μmol/L, and (13.21±1.06), respectively, in group M4, and (10 170.13±1 112.37) U/L, (11 470.56±1 108.40) U/L, (12.75±1.55) μmol/L, and (15.07±1.58), respectively, in group M5. The levels of ALT, AST, and TBil and Ishak score were (1 016.35±163.47) U/L, (952.30±103.91) U/L, (7.77±0.62) μmol/L, and (3.50±0.21), respectively, in group E1, (42.10±6.20) U/L, (126.72±13.33) U/L, (3.41±0.53) μmol/L, and (2.01±0.40), respectively, in group E2, (44.21±4.30) U/L, (216.71±35.88) U/L, (3.47±0.44) μmol/L, and (2.13±0.25), respectively, in group E3, (2 909.69±212.14) U/L, (2 988.43±333.70) U/L, (7.03±0.93) μmol/L, and (4.70±0.50), respectively, in group E4, and (7 874.26±799.60) U/L, (10 940.54±947.35) U/L, (10.53±1.09) μmol/L, and (8.60±0.83), respectively, in group E5. Groups M1-M5 had significantly higher levels of ALT, AST, and TBil than group C (all P < 0.01), and groups M1-M4 had significantly higher levels of AST and ALT than groups E1-E4 (all P < 0.01), while there were no significant differences in the levels of AST and ALT between groups M5 and E5 (both P > 0.05). The pathological sections of liver tissue showed that compared with group M, group E had significant reductions in the degree of necrosis and Ishak score (both P < 0.05). Conclusion: Intraperitoneal transplantation of human liver-derived stem cells has a protective effect against ConA-induced acute liver injury in mice, and the injection at 6 and 12 hours in advance has the best protective effect.