表没食子儿茶素没食子酸酯(EGCG)对ConA所致小鼠肝损伤的保护作用

目的探讨表没食子儿茶素没食子酸酯(EGCG)对刀豆蛋白A(ConA)诱导的小鼠肝损伤的保护作用及其作用机制。方法 40只小鼠随机分为对照组、EGCG对照组、ConA模型组及EGCG+ConA组。采用ELISA法检测血清ALT、AST、TNF-α、IFN-γ、IL-4及IL-6的变化,HE法检测小鼠肝脏形态学改变。结果 ConA模型组小鼠血清转氨酶水平明显高于对照组(P<0.05),EGCG对照组与对照组比较无变化(P>0.05)。与ConA模型组相比,EGCG+ConA组小鼠血清转氨酶水平下降(P<0.05)。ConA模型组小鼠肝脏病理切片示较多肝细胞坏死,对照组和EGCG对照组小鼠肝脏形态学基本正常,EGCG+ConA组示肝细胞炎症坏死程度较ConA模型组有所减轻。ConA模型组小鼠血清TNF-α、IFN-γ、IL-4及IL-6水平明显高于对照组(P<0.05),EGCG对照组与对照组比较无明显差异(P>0.05)。EGCG+ConA组小鼠血清TNF-α、IFN-γ、IL-4及IL-6水平均下降,与ConA模型组比较有显著性差异(P<0.05)。结论 EGCG对ConA所致小鼠肝损伤有明显的保护作用,可能与其对炎性因子的调节有关。     

(-)-Epigallocatechin-3-gallate protects mice from concanavalin A-induced hepatitis through suppressing immune-mediated liver injury

(-)-Epigallocatechin-3-gallate (EGCG) is the major active component of green tea. Increasing evidence has suggested that EGCG exhibits anti-inflammatory, anti-oxidant and immunosuppressive effects. In this study, we investigated the effect of EGCG on concanavalin A (ConA)-induced hepatitis (CIH) in mice, a model of immune-mediated liver injury in humans. We pretreated mice with EGCG before ConA injection, and then measured alanine aminotransferase (ALT) levels in plasma, inflammatory infiltration and hepatocyte apoptosis in liver. Potential therapeutic mechanisms were elucidated further by measuring several inflammatory mediators. Mice pretreated with EGCG exhibited much less increased ALT levels in plasma, reduced inflammatory infiltration and hepatocyte apoptosis in liver compared with control mice pretreated with vehicle solutions. We further investigated the mechanisms of the protective effects of EGCG. In EGCG-pretreated mice, we found abrogated tumour necrosis factor (TNF)-alpha and interferon (IFN)-gamma at both protein levels in plasma and mRNA levels in liver. At the same time, the concentration of nitrite in plasma and inducible nitric oxide synthase production in liver were both down-regulated in these mice. Moreover, IFN-inducible protein-10 and macrophage inflammatory protein-1alpha expressions in liver were decreased significantly. Therefore, EGCG is capable of regulating immune-mediated liver injury in vivo. The protective effect depended on its suppressive effect on the production of important inflammatory mediators.     

表没食子儿茶素没食子酸酯( EGCG) 对免疫性肝损伤的保护作用及其机制研究

目的:探讨表没食子儿茶素没食子酸酯(EGCG)对雷公藤甲素(TP)诱导的免疫性肝损伤的保护性作用及其作用机制。方法:雌性C57BL/6 小鼠随机分为4 组,即正常对照组、EGCG 对照组、TP 组、EGCG 治疗组。以赖氏法检测血清中ALT 水平,以分光光度法检测肝匀浆中丙二醛(MDA)、超氧化物歧化酶(SOD)和还原型谷胱甘肽(GSH)的变化情况,以HE染色观测小鼠肝脏组织形态学变化,以ELISA 方法检测肝脏中白细胞介素(IL)-17 和IL-6 的表达水平,以Western blot 方法检测肝脏中Toll 样受体4(TLR4)的表达情况。结果:TP 组小鼠血清转氨酶水平明显高于正常对照组(P<0.005),EGCG 对照组与正常对照组比较无变化(P>0.05),而EGCG 治疗组小鼠血清转氨酶水平与TP 组相比下降明显(P<0.005)。TP 组小鼠肝脏病理切片示较多肝细胞坏死和中性粒细胞浸润,EGCG 对照组和正常对照组小鼠肝脏形态学基本正常,EGCG 治疗组示肝细胞炎症坏死程度较TP 组有大幅减轻。TP 组小鼠肝脏中MDA、IL-17 及IL-6 水平明显高于正常对照组(P<0.005),而SOD和GSH 水平明显低于正常对照组(SOD,P<0.05;GSH,P<0.005),EGCG 对照组与正常对照组比较无变化(P>0.05),EGCG 治疗组小鼠肝脏中MDA、IL-17 及IL-6 水平均下降明显(P<0.005),而SOD 和GSH 水平均增高,与TP 组比较有显著性差异(SOD,P<0.05;GSH,P<0.005)。TP 组肝脏TLR4 蛋白表达水平高于正常对照组,EGCG 对照组与正常对照组比较无变化(P>0.05),而EGCG 治疗组TLR4 水平显著降低。结论:EGCG 对TP 所致小鼠肝损伤有明显的保护作用,可能与其抗氧化作用及对炎症因子的调节有关。     

Quercetin Protects Mice from ConA-Induced Hepatitis by Inhibiting HMGB1-TLR Expression and Down-Regulating the Nuclear Factor Kappa B Pathway

The dietary flavonoid quercetin has hepatoprotective effects. We analyzed the effects of quercetin on concanavalin A (ConA)-induced hepatitis in mice and its underlying molecular mechanisms of action. Mice were administered quercetin (50 mg/kg body weight, i.p.) or vehicle 30 min before intravenous administration of ConA. Quercetin pretreatment significantly reduced the ConA-induced elevations in plasma aminotransferase concentrations and liver necrosis, as well as reducing serum concentrations of the pro-inflammatory cytokines tumor necrosis factor (TNF)-α, interferon-γ, and interleukin-4. Quercetin pretreatment also reduced expression of high-mobility group box 1 protein (HMGB1) and toll-like receptor (TLR)-2 and TLR-4 messenger RNA (mRNA) and protein in liver tissues. Quercetin pretreatment significantly inhibited degradation of inhibitory kappa B alpha and modulated ConA-induced nuclear translocation in the liver of nuclear factor kappa B (NF-κB) p65. These results demonstrate that quercetin protects against ConA-mediated hepatitis in mice by attenuating the HMGB1–TLRs–NF-κB signaling pathway.     

EGCG对ConA诱导的肝损伤小鼠NF-κB和ICAM-1表达的影响

目的通过观察表没食：于儿茶素没食子酸酯（EGCG）对ConA诱导的急性肝损伤小鼠肝组织中NF-κB及ICAM-1表达的影响,来探讨EGCG对小鼠的肝保护机制。方法C57BL／6小鼠分成4组：对照组、EGCG对照组、ConA模型组．EGCG＋ConA组。EGCG对照组及EGCG＋ConA组小鼠给予EGCGEl服（5mg／kg）10d后,予模型组小鼠静脉注射ConA（15mg／kg）建造肝损伤模型。采血及留取肝组织,HE法检测肝组织病理变化,ELISA法检测NF-KB及ICAM-1的表达。结果ConA模型组小鼠肝损伤明显,NF-κB及ICAM-1的表达明显增多,与对照组比较有显著性差异（P〈0．05）;EGCG治疗组肝损伤减轻且伴NF-KB及ICAM-1的表达下降,与模型组比较差异明显（P〈0．05）。结论EGCG对ConA诱导的免疫性肝损伤小鼠有保护作用．其机制可能与调节NF-κB及ICAM-1的表达有关。     

微小RNA-7敲减对ConA诱导的小鼠急性肝损伤的影响

目的:研究微小RNA-7(miR-7)敲减(KD)对急性肝损伤(ALI)模型小鼠的影响。方法:野生型(WT)小鼠和miR-7KD小鼠腹腔注射30 mg/kg刀豆蛋白(ConA)建立急性肝损伤模型;48 h后,观察小鼠肝脏的形态、重量及其脏器指数变化;HE染色观察小鼠肝脏组织病理学变化;血清学方法检查血清中谷丙转氨酶(ALT)的水平;ELISA法检测血清中细胞因子IL-4和IFN-γ的水平;流式细胞术检测肝脏组织中CD4~+T细胞的比例及其相关的细胞因子IL-4和IFN-γ的表达变化。结果:与对照组相比,miR-7敲减后急性肝损伤小鼠的肝脏组织颜色变浅,重量减轻,重量指数明显增加(P0.05);HE染色显示miR-7KD小鼠血清炎症细胞浸润显著增多;血清学方法检测发现急性肝损伤小鼠血清ALT的水平明显上升(P0.05);ELISA法检测显示miR-7KD小鼠血清中IFN-γ水平明显升高(P0.01),而IL-4的表达水平则明显降低(P0.01);流式细胞术检测结果显示,miR-7KD小鼠肝脏中CD4+T细胞比例显著升高(P0.01),其相关的细胞因子IFN-γ的表达水平也显著上调(P0.01),而IL-4的水平没有发生明显变化。结论:敲减miR-7基因可明显促进ConA诱导的小鼠急性肝损伤。     

淫羊藿苷对ConA诱导的小鼠肝脏损伤保护机理的研究

目的:利用刀豆蛋白A(ConA)诱导建立小鼠肝炎模型,观察淫羊藿苷对该损伤模型保护作用的细胞免疫学和分子免疫学机制。方法:采用C57BL/6雄性小鼠,随机分为淫羊藿苷+ConA组、生理盐水+ConA组、淫羊藿苷+生理盐水组。小鼠尾静脉注射ConA,建立T细胞介导的免疫性肝脏损伤模型;采用转氨酶试剂盒测定各组小鼠血液中转氨酶含量;组织病理学观察实验小鼠肝脏组织和肝细胞坏死变化;采用ELISA试剂盒测定血清中炎性细胞因子IFN-γ、TNF-α含量;流式细胞术观察注射ConA后肝脏淋巴细胞的活化变化。结果:与ConA对照组相比,淫羊藿苷干预组小鼠血液中ALT和AST水平明显降低,P<0.01;IFN-γ、TNF-α含量明显降低,P<0.05;H&E染色可见淫羊藿苷干预组小鼠肝细胞核完整,未见炎性细胞的浸润,而ConA对照组小鼠肝细胞核固缩,部分核膜破裂,肝组织内有炎症细胞和红细胞浸润;流式细胞技术发现淫羊藿苷可明显延缓由ConA引起的肝脏NKT细胞的活化,减弱T细胞的浸润。结论:淫羊藿苷对ConA诱导的小鼠肝脏损伤有明显的保护作用,其机理可能与淫羊藿苷降低血液中IFN-γ、TNF-α表达及影响肝脏NKT细胞的活化有关。     

Curcumin Protects Against Concanavalin A-Induced Hepatitis in Mice Through Inhibiting the Cytoplasmic Translocation and Expression of High Mobility Group Box 1

The aims of this study were to examine the anti-inflammatory effect of curcumin on concanavalin A (ConA) induced hepatitis in mice, and to elucidate its underlying molecular mechanisms. Mice received curcumin by gavage before ConA intravenous administration. The results showed that curcumin pretreatment attenuated ConA-induced hepatitis. Enzyme linked immunosorbent assay (ELISA) results showed that serum levels of high mobility group box 1 (HMGB1) increased at 4 h and reached its peak value at 12 h after challenge with ConA; but this increase was significantly inhibited by curcumin. Furthermore, curcumin significantly decreased the HMGB1 translocation from nucleus to cytoplasm of hepatocytes in ConA-induced mice. The levels of HMGB1 mRNA and protein expression in the liver were also significantly lowered in curcumin-treated mice. In addition, curcumin inhibited intrahepatic expression of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6 protein. In conclusion, the results indicated that curcumin protected against ConA-induced hepatitis in mice; and the beneficial effects may be partly through inhibition of HMGB1 translocation in hepatocytes, release into the plasma and expression in livers.     

EGCG对ConA诱导的肝损伤小鼠TNF-α与IL-17表达的影响

目的探讨表没食子儿茶素没食子酸酯(EGCG)对ConA诱导的小鼠肝损伤的保护作用及其作用机制。方法 40只小鼠随机分为正常对照组、EGCG对照组、ConA模型组及EGCG+ConA组。采用HE法检测小鼠肝脏形态学改变,ELISA法检测血清ALT、AST的变化,采用免疫组化方法和Western blot方法检测各组小鼠肝组织中TNF-α与IL-17的变化。结果 ConA模型组ALT、AST的含量比对照组明显升高(0.05),EGCG对照组与正常对照组比较无变化(0.05),EGCG+ConA组比ConA模型组含量下降(0.05)。ConA模型组小鼠肝脏显示较多肝细胞坏死,正常对照组和EGCG对照组小鼠肝脏正常,EGCG+ConA组肝细胞炎症坏死程度较ConA模型组有所减轻。ConA模型组小鼠肝组织中TNF-α与IL-17水平较正常对照组和EGCG对照组明显升高(0.05),EGCG对照组与正常对照组比较无明显差异(0.05),EGCG+ConA组比ConA模型组下降(0.05)。结论 EGCG对ConA所致小鼠肝损伤有明显的保护作用,机制可能与其对炎性因子TNF-α与IL-17的调节有关。     

激活FXR抑制MRL/lpr狼疮小鼠肝损害的研究

 目的:观察法尼酯衍生物X受体（FXR）激活是否减轻MRL/lpr狼疮小鼠肝损害。方法:检测FXR在MRL/lpr狼疮小鼠及正常BALB/c小鼠肝脏的表达;观察BALB/c小鼠和鹅去氧胆酸（CDCA）激活FXR的MRL/lpr小鼠再以伴刀豆球蛋白A(ConA)诱导肝脏炎症反应后的肝脏酶学、炎症因子及病理学的变化。结果:FXR在MRL/lpr狼疮小鼠肝脏中低表达;ConA能在MRL/lpr小鼠诱导出较对照BALB/c小鼠更严重的肝损害;激活FXR减轻MRL/lpr狼疮小鼠ConA诱导的肝脏炎症损伤,并减少一系列炎症因子的释放。结论: CDCA激活FXR 后,能减轻狼疮小鼠肝脏损害。FXR可能是系统性红斑狼疮肝损害的一个保护性因素,激活FXR可能成为狼疮肝损害的一个治疗途径。     

NCPP treatment alleviates ConA-induced hepatitis via reducing CD4+T activation and NO production

Corynebacterium parvum (CP), a kind of immunomodulator, has been well documented in many diseases. Non-cell C. parvum product (NCPP) is a newly-found nano-preparation. To investigate the effect of NCPP on Con A-induced murine severe hepatitis, we pretreated mice with NCPP intraperitoneally. After 12 h, ConA (25 μg/g body wt) was injected intravenously to provoke severe hepatitis and the degree of liver injury was evaluated by serum transaminase analysis and heptatic tissue pathology. Results have shown that levels of serum transaminase and degree of liver injury in ConA/NCPP groups had significantly declined than those in ConA/PBS groups. Notably, results of flow cytometry have demonstrated that activation of CD4+T cells in ConA/NCPP groups has been down-regulated, compared with ConA/PBS groups. Further, levels of serum and KC-related nitric oxide (NO) was displayed significantly lower in ConA/NCPP groups than those in ConA/PBS groups. The results indicate that NCPP may alleviate ConA-induced hepatitis by reducing CD4+T activation and NO production.     

High mobility group box chromosomal protein 1 in acute-on-chronic liver failure patients and mice with ConA-induced acute liver injury

High mobility group box chromosomal protein 1 (HMGB1) is an important proinflammatory molecule in many inflammatory disorders, but little is known about its role in acute-on-chronic liver failure (ACLF). Here, we investigated the relationship between the expression of HMGB1 and the disease onset and severity of ACLF patients and mice with acute liver injury/failure induced by concanavalin A (ConA). Peripheral blood mononuclear cells (PBMCs) and serum from ACLF patients were collected, and a mouse model of acute liver injury/failure was induced by ConA. HMGB1 mRNA expression in patient PBMCs or in murine livers and serum HMGB1 protein in ACLF patients and mice were assayed by RT-PCR and Western blotting, respectively. HMGB1 translocation in hepatocytes of ConA-treated mice was assessed by immunohistochemical staining. Up-regulated HMGB1 mRNA levels in PBMCs and accumulated protein in serum were both correlated with disease severity in ACLF patients. In the animal model, HMGB1 levels increased at 4 h and reached its peak value at 8-12 h after challenge with ConA, which suggests that HMGB1 is a relatively late proinflammatory cytokine compared with TNF-α. Translocation of HMGB1 from the nucleus to the cytoplasm in hepatocytes was correlated with the severity of liver injury in mice. While specific anti-HMGB1 antibodies and nicotine protected mice from acute liver injury/failure by reducing mortality and improving liver tissue injury, treatment with recombinant HMGB1 led to an increased mortality due to ConA challenge. Thus, the data from the present study suggest that HMGB1 plays a critical role in the systemic inflammation of ACLF and could be a potential therapeutic target in the treatment of ACLF.     

Protective role of urinary trypsin inhibitor in lung expression of proinflammatory cytokines accompanied by lethal liver injury in mice

Urinary trypsin inhibitor (UTI), a serine protease inhibitor, has been widely used for patients with inflammatory disorders including disseminated intravascular coagulation, shock, and pancreatitis in Japan, since it reportedly exhibits anti-inflammatory properties aside from its blocking of the protease pathway both in vitro and in vivo. In accordance with other reports, our previous studies using UTI-null (–/–) mice showed that UTI protects against systemic inflammatory responses in vivo. Recently, we also revealed the protective role of UTI against lethal liver injury induced by lipopolysaccharide and D-galactosamine (LPS/D-GalN). However, the anti-inflammatory role of UTI has not been sufficiently clarified using the model. The present study determined the effects of endogenous UTI on lung inflammation accompanied by lethal liver injury induced by LPS/D-GalN in the context of the lung expression of proinflammatory cytokines. After LPS/D-GalN challenge, protein levels of interleukin-1β, tumor necrosis factor-α, macrophage inflammatory protein-1α, and macrophage chemoattractant protein-1 in the lung homogenates were elevated in both genotypes, but to a greater extent in UTI (–/–) than in WT mice (P < 0.05 for TNF-α). The IFN-γ level was also significantly greater in LPS/D-GalN challenged UTI (–/–) mice than in other mice (P < 0.01). These results suggest that UTI protects against the local inflammatory response accompanied by severe liver injury, which supports its anti-inflammatory properties in vivo.     

Toll-like receptor 2 mediates inflammatory cytokine induction but not sensitization for liver injury by Propioni- bacterium acnes

Recognition of Gram-positive bacteria by Toll-like receptor 2 (TLR2) induces activation of proinflammatory pathways. In mice, sensitization with the Gram-positive Propionibacterium acnes followed by a challenge with the TLR4 ligand, lipopolysaccharide (LPS), results in fulminant hepatic failure. Here, we investigated the role of TLR2 in liver sensitization to LPS-induced injury. Stimulation of Chinese hamster ovary cells and peritoneal macrophages with heat-killed P. acnes required expression of TLR2 but not of TLR4, suggesting that P. acnes was a TLR2 ligand. Cell activation by P. acnes was myeloid differentiation primary-response protein 88 (MyD88)-dependent, and it was augmented by coexpression of CD14 in mouse peritoneal macrophages. In vitro, P. acnes behaved as a TLR2 ligand and induced TLR4 hetero- and TLR2 homotolerance in peritoneal macrophages. In vivo priming of wild-type mice with P. acnes, but not with the selective TLR2 ligands peptidoglycan and lipotheicoic acid, resulted in hepatocyte necrosis, hyperelevated serum levels of tumor necrosis factor alpha (TNF-alpha), interleukin (IL)-6, interferon-gamma (IFN-gamma), and IL-12 (p40/p70), and increased RNA expression of proinflammatory cytokines (IL-12p40, IL-1alpha, IL-6, IL-1beta, IL-18, IFN-gamma) in the liver after a LPS challenge. Furthermore, P. acnes priming sensitized TLR2-deficient (TLR2-/-) but not MyD88-/- mice to LPS-induced injury, evidenced by hepatocyte necrosis, increased levels of serum TNF-alpha, IFN-gamma, IL-6, and liver proinflammatory cytokine mRNA expression. IFN-gamma, a cytokine sensitizing to endotoxin, was induced by P. acnes in splenocytes of TLR2-/- and TLR9-/- but not MyD88-/- mice. These results suggest that although P. acnes triggers TLR2-mediated cell activation, TLR2-independent but MyD88-dependent mechanisms mediate in vivo sensitization by P. acnes for LPS-induced liver injury.     

Vesnarinone inhibits immune-mediated but not fas (CD95) agonist-mediated hepatic injury

Previous studies have shown that the administration of concanavalin A (ConA) into mice induces immune-mediated liver injury, which can be largely abrogated by neutralizing tumor necrosis factor(TNF)α. Vesnarinone is an experimental drug which is known to inhibit TNFα release. Here we demonstrate that vesnarinone inhibits ConA-induced hepatic injury. In a dose-dependent manner, vesnarinone inhibits in several mouse strains the increase of serum aminotransferase concentrations. Additional experiments show that vesnarinone inhibits ConA-mediated accumulation of DNA fragmentation in the liver. Furthermore, the drug significantly reduces the levels of circulating TNFα and interleukin-6 (IL-6). Vesnarinone does not modulate TNFα and IL-6 action on hepatic cells, as shown by its failure to reduce the cytokine specific-stimulation of acute phase plasma proteins in the rat hepatoma H-35 cell line. Neither vesnarinone nor anti-TNFα protect against direct liver injury induced by a sublethal dose of agonist anti-Fas (CD95) antibody. Taken together, these results suggest that vesnarinone blocks hepatic injury, in part by inhibiting the release of TNFα in vivo.     

Lactobacillus casei Zhang 对扑热息痛诱导的小鼠急性肝损伤的保护作用

目的:研究益生菌Lactobacillus casei Zhang(Lcz)对扑热息痛(APAP)所致小鼠急性肝损伤的保护作用及其机制。方法:C57BL/6 小鼠被随机分为空白组(Ctrl)、APAP 诱导急性肝损伤模型组(Acetaminophen ,APAP)、阳性药物组(N-Acetylcysteine,NAC)、Lcz 预防组(Lcz/ APAP)和Lcz 对照组(Lcz)。Lcz(1伊109 CFU/ ml)连续灌胃30 d 后,NAC 组在APAP 处理前1 h 腹腔注NAC(150 mg/ kg)。APAP、NAC 以及Lcz/ APAP 组均腹腔注射APAP(300 mg/ kg)。APAP 作用18 h 后,采集血液和收集肝脏组织,检测血清中谷丙转氨酶(ALT)和谷草转氨酶(AST)的水平。通过Western blot 检测肝脏组织中血红素氧化酶(HO-1)、超氧化物歧化酶2(SOD2)、Bcl-2 以及TLR4 的表达水平。结果:Lcz 能抑制APAP 诱导的急性肝损伤血清中ALT 和AST 水平。Lcz 提高了HO-1、SOD2 和Bcl-2 的蛋白表达水平,而降低了APAP 诱导的TLR4 的表达。结论:益生菌Lcz对APAP 诱导的小鼠急性肝损伤有保护作用,其保肝作用机制可能与其抗氧化和抗炎活性有关。     

Chlorogenic Acid Attenuates Lipopolysaccharide-Induced Acute Kidney Injury by Inhibiting TLR4/NF-κB Signal Pathway

Chlorogenic acid (CGA), a polyphenolic compound, exists widely in medicinal herbs, which has been shown a strong antioxidant and anti-inflammatory effect. This study investigated the protective effects and mechanism of CGA on lipopolysaccharide (LPS)-induced acute kidney injury (AKI). Treatment of CGA successfully ameliorates LPS-induced renal function and pathological damage. Moreover, CGA dose-dependently suppressed LPS-induced blood urea nitrogen (BUN), creatinine levels, and inflammatory cytokines TNF-α, IL-6, and IL-1β in serum and tissue. The relative proteins’ expression of TLR4/NF-κB signal pathway was assessed by western blot analysis. Our results showed that CGA dose-dependently attenuated LPS-induced kidney histopathologic changes, serum BUN, and creatinine levels. CGA also suppressed LPS-induced TNF-α, IL-6, and IL-1β production both in serum and kidney tissues. Furthermore, our results showed that CGA significantly inhibited the LPS-induced expression of phosphorylated NF-κB p65 and IκB as well as the expression of TLR4 signal. In conclusion, our results provide a mechanistic explanation for the anti-inflammatory effects of CGA in LPS-induced AKI mice through inhibiting TLR4/NF-κB signaling pathway.     

NK T cells stimulated with a ligand for TLR2 at least partly contribute to liver injury caused by Escherichia coli infection in mice

Fas ligand (Fas L) expression was induced on intrahepatic NK1.1(+) T cells in vivo after an intraperitoneal inoculation of Escherichia coli. Liver injury after E. coli infection, as assessed by serum GPT level and histological examination, was significantly reduced in Jalpha281(-/-) mice lacking NK1.1(+) T cells or in gld/gld mice bearing mutated Fas L, indicating that NK T cells at least partly contribute to E. coli-induced liver injury in a Fas/Fas L-dependent manner. Bacterial numbers in organs and cytokine levels in serum of Jalpha281(-/-) mice did not differ from those of Jalpha281(+/+) mice following E. coli infection. Intrahepatic NK1.1(+) T cells, which preferentially expressed Toll-like receptor 2 (TLR2) mRNA, responded in vitro to synthetic lipoprotein, a ligand for TLR2, by inducing Fas L expression on their surface. In a manner analogous to E. coli infection, lipoprotein and LPS could additively induce Fas L expression on NK1.1(+) T cells, leading to liver injury in vivo in normal mice but not in gld/gld mice. In conclusion, it is suggested that induction of Fas L on NK T cells in response to bacterial components such as lipoproteins plays an important role in pathogenesis of E. coli-induced liver injury in mice.     

Cross-regulation by TLR4 and T cell Ig mucin-3 determines severity of liver injury in a CCl4-induced mouse model

Acute liver injury is a common pathological basis for a variety of acute liver diseases in the clinic, which can eventually lead to liver fibrosis and even liver failure. In this study, we found that T cell Ig and mucin domain protein 3 (Tim-3) and TLR4 receptors play important roles in CCl4-induced acute liver injury. Tim-3 is a negative regulator that is expressed by T cells and macrophages. Using antibodies against Tim-3 (anti-Tim-3 Ab), we studied the Tim-3 signal in an animal model of acute liver injury and found that a large number of inflammatory factors were upregulated. In vitro experimental data shown that anti-Tim-3 Ab treatment increased interferon-ɣ production by concanavalin A (ConA)-stimulated spleen T cells, and we found that the expression level of interleukin (IL)-6 was increased in a macrophage/spleen T cell coculture system, while administration of galectin-9 (Gal-9, a Tim-3 ligand) reduced the IL-6 production. This indicates the importance of the Tim-3/Gal-9 signalling pathway in maintaining hepatic homeostasis. The Tim-3 signalling pathway inhibits TLR4-mediated NF-κB activity, and an anti-Tim-3 Ab does not affect the liver injury in TLR4-deficient mice. Regulation between Tim-3 and TLR4 determines the severity of liver damage. The negative regulation of Tim-3 reflects the protective mechanisms of patients with impaired liver function, and these results provide important information about innate and adaptive responses in the regulation of liver damage. This finding is potentially important for the study of early liver injury.     

Artesunate Protects LPS-Induced Acute Lung Injury by Inhibiting TLR4 Expression and Inducing Nrf2 Activation

Artesunate, a derivative of artemisinin, has been reported to have anti-inflammatory property. However, few studies showed the protective effects of artesunate on lung injury. In this study, we aimed to investigate the effects of artesunate on LPS-induced lung injury in mice. The mice were treated with artesunate 1 h before or after LPS treatment. The effects of artesunate on lung MPO activity and malondialdehyde (MDA) content were detected. The lung wet/dry radio and the numbers of inflammatory cells in BALF were also measured. ELISA was used to evaluate the levels of TNF-α, IL-1β, and IL-6 in BALF. Western blot analysis was adapted to detect TLR4 and Nrf2 signaling pathways. The results showed that artesunate protected against LPS-induced ALI by decreasing the numbers of inflammatory cells, lung edema, MPO activity, and MDA content. Furthermore, artesunate significantly inhibited the levels of TNF-α, IL-1β, and IL-6. Artesunate also inhibited LPS-induced IL-6 and IL-8 production in the A549 cells. In addition, artesunate dose-dependently suppressed LPS-induced TLR4 expression and NF-κB activation. The expression of Nrf2 and HO-1 were also up-regulated by artesunate. The data suggest that artesunate possesses anti-inflammatory and anti-oxidant properties against LPS-induced ALI via inhibiting TLR4 signaling pathway and activating Nrf2 signaling pathway.