Protective effect of SKLB010 against d-galactosamine/lipopolysaccharide-induced acute liver failure via nuclear factor-κB signaling pathway in macrophages

Acute liver failure is characterized by the sudden loss of hepatic function and a high mortality. SKLB010, a derivative of thiazolidinediones, has been proved to be effective in protecting mice from acute liver failure caused by concanavalin A and carbon tetrachloride in our previous work. The purpose of the current study was to evaluate whether SKLB010 could prevent acute liver injury caused by d-galactosamine/lipopolysaccharide (LPS) in mice, and to investigate the underlying mechanisms. In the macrophage-mediated D-GalN/LPS model of acute liver injury, serum enzyme activity was suppressed and liver injury was attenuated by SKLB010. The serum levels of TNF-α and hepatic TNF-α mRNA expression were also markedly decreased after the treatment of SKLB010. In the liver of mice receiving injections of D-GalN/LPS, hepatocytes apoptosis and the infiltration of monocytes/macrophages were blocked by SKLB010. Furthermore, the survival rate of mice following D-GalN/LPS treatment was significantly improved by a single injection with SKLB010. In vivo, the luminescence intensity was suppressed by SKLB010 in NF-κB-luc mice after D-GalN/LPS treatment. In vitro, the production of tumor necrosis factor (TNF)-α and nitrite/nitrate in LPS-stimulated RAW264.7 macrophages was decreased by SKLB010 in a dose-dependent manner. Our further studies demonstrated that SKLB010 inhibited the phosphorylation of IκBα and p38MAPK, and the DNA binding activity of NF-κB in RAW264.7 cells. In conclusion, treatment with only a single injection of SKLB010 could significantly attenuate acute inflammation in mice induced by D-GalN/LPS, and these effects are likely associated with the inhibition of NF-κB activity.     

Vitisin A suppresses LPS-induced NO production by inhibiting ERK,p38, and NF-κB activation in RAW 264.7 cells

Vitisin A, a resveratrol tetramer isolated from Vitis vinifera roots, exhibits antioxidative, anticancer, antiapoptotic, and anti-inflammatory effects. It also inhibits nitric oxide (NO) production. Here, we examined the mechanism by which vitisin A inhibits NO production in lipopolysaccharide (LPS)-induced RAW 264.7 macrophage cells. Vitisin A dose dependently inhibited LPS-induced NO production and inducible NO synthase (iNOS) expression. In contrast, the production of proinflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) was not altered by vitisin A. To investigate the signaling pathway for NO inhibition by vitisin A, we examined nuclear factor-κB (NF-κB) activation in the mitogen-activated protein kinase (MAPK) pathway, an inflammation-induced signal pathway in RAW 264.7 cells. Vitisin A inhibited LPS-induced extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 phosphorylation and suppressed LPS-induced NF-κB activation in RAW 264.7 cells. This suggests that vitisin A decreased NO production via downregulation of ERK1/2 and p38 and the NF-κB signal pathway in RAW 264.7 cells.     

双环醇对脂多糖诱导巨噬细胞iNOS蛋白的表达和NF-κB活化的抑制作用

目的炎症是肝炎病毒或其它因素所致的肝损伤的一个共同特征,该文目的系研究抗肝炎新药双环醇对与炎症反应相关分子的调节作用。方法以无毒性浓度双环醇预先与巨噬细胞株RAW264.7和小鼠腹腔巨噬细胞温孵1h后,加入一定量脂多糖(LPS)共同培养适当时间以诱导上述细胞的活化,培养上清中NO2-的含量和TNF-α的水平分别用Griess试剂及L929细胞株生物法测定,用Westernblot方法测定iNOS蛋白的表达和NF-κB的活化。结果双环醇在0.1～0.5mmol.L-1剂量依赖性降低1mg.L-1LPS引起的RAW264.7和小鼠腹腔巨噬细胞NO的释放以及TNF-α的分泌,双环醇0.5mmol.L-1能够明显抑制1mg.L-1LPS引起的iNOS蛋白的表达和NF-κB的活化。结论双环醇对与炎症相关的调控因子iNOS蛋白的表达和NF-     

Okra polysaccharide-2 plays a vital role on the activation of RAW264.7 cells by TLR2/4-mediated signal transduction pathways

Polysaccharide is the main active component of okra (Abelmoschus esculentus L.) and it can effectively stimulate the activation of macrophages. However, the immune regulatory mechanism is still not clear. Therefore, the present study aimed to reveal the possible mechanism by investigating the effect of okra polysaccharide-2 (RPS-2) on Toll-like receptor (TLR) 2/4-mediated signal transduction pathways in RAW264.7 murine macrophage cells. In order to confirm whether RPS-2 stimulated macrophages activation via TLR2 or TLR4, RAW264.7 murine macrophage cells were pretreated with TLR2/4 inhibitors for 1 h before RPS-2 treatment, and then the NO, IL-10, TNF-α levels were tested. The results indicated that both TLR2 and TLR4 were the keys of immune regulatory effect of RPS-2. Afterwards, the effect of RPS-2 on NF-κB and MAPKs signaling pathways were studied by western blot analysis. It showed RPS-2 induced the phosphorylation of p65, IκBα, p38, ERK1/2 and JNK. At the same time, the specific inhibitors reduced these phosphorylation levels as well as NO, IL-10 and TNF-α amounts. In a word, RPS-2 activated macrophages by NF-κB and MAPKs signal transduction pathways.     

丹参酮II-A通过调控TLR4/IκBα/NFκB信号通路抑制LPS诱导的细胞炎症

目的建立脂多糖(LPS)诱导的小鼠单核巨噬细胞(RAW264.7)炎症模型,探究丹参酮II-A(Tan IIA)的抗炎活性及其机制。方法CCK-8法测定Tan IIA对细胞活力的影响;迁移小室测定Tan IIA对LPS诱导细胞迁移能力作用;ELISA法测定细胞上清液中小鼠肿瘤坏死因子α(tumor necrosis factoralpha,TNF-α)、白介素6(interleukin 6,IL-6)、IL^-1β、单核细胞趋化蛋白-1(monocyte chemoattractant protein,MCP-1)的含量;Western blot法检测基质金属蛋白酶2(matrix metalloproteinases,MMP-2)、MMP-9、Toll样受体-4(TLR4)、IκB-α、p-IκB-α、NFκB和p-NFκB蛋白的表达。结果Tan IIA对LPS诱导的RAW264.7细胞培养液中炎症因子TNF-α、IL-6、IL^-1β和MCP-1的分泌有明显的抑制作用;明显下调MMP-2、MMP-9、TLR4、p-IκB-α和p-NFκB的蛋白的表达,抑制IκB-α磷酸化和NFκB的入核和活化。结论Tan IIA可通过抑制MMP-2和MMP-9的表达以及TLR4/κB-α/NF-κB信号通路,调控TNF-α、IL-6、IL^-1β等炎症因子的释放而发挥抗炎活性。     

基于TLR4/MyD88/NF-κB信号通路研究黄连素对小鼠巨噬细胞极化的干预作用

目的:基于Toll样受体4(TLR4)/髓样分化因子88(MyD88)/核因子κB(NF-κB)信号通路研究黄连素对小鼠巨噬细胞极化的影响。方法:以小鼠巨噬细胞RAW264.7为对象,以阿托伐他汀钙为阳性对照,经脂多糖(LPS)诱导以复制炎症细胞模型,采用酶联免疫吸附测定法检测低、中、高剂量黄连素(5、10、20μmol/L)作用24 h后细胞培养液中肿瘤坏死因子α(TNF-α)、白细胞介素6(IL-6)、NF-κB含量,采用实时荧光定量聚合酶链反应法检测细胞中TLR4、MyD88 mRNA的表达水平,采用Western blotting法检测细胞中TLR4、MyD88、诱导型一氧化氮合酶(iNOS)、CD206蛋白的表达水平。结果:与空白对照组比较,LPS诱导组细胞培养液中TNF-α、IL-6、NF-κB含量,细胞中TLR4、MyD88 mRNA的相对表达量以及TLR4、MyD88、iNOS蛋白相对表达量均显著升高(P<0.05)。与LPS诱导组比较,阿托伐他汀钙组和黄连素中、高剂量组TNF-α、IL-6含量,TRL4、MyD88 mRNA及其蛋白的相对表达量以及各给药组NF-κB含量和i NOS蛋白的相对表达量均显著降低,且黄连素高剂量组NF-κB含量显著低于阿托伐他汀钙组(P<0.05);阿托伐他汀钙组和黄连素高剂量组CD206蛋白的相对表达量均显著升高,且黄连素高剂量组CD206蛋白的相对表达量显著高于阿托伐他汀钙组(P<0.05)。结论:不同剂量的黄连素均可不同程度地干预小鼠巨噬细胞极化,其机制可能与调控TLR4/MyD88/NF-κB信号通路有关。     

Protective effect of forsythoside B against lipopolysaccharide-induced acute lung injury by attenuating the TLR4/NF-κB pathway

Acute lung injury (ALI), which is mainly triggered by infection, pneumonia, vasculitis, and sepsis, has no specific and effective therapy except for primary supportive treatment or bedside care. Excessive inflammation caused by innate immune cells is the major characteristic of ALI. Forsythoside B, a phenylethanoside compound, possesses good antioxidant and anti-bacterial properties in vivo and in vitro. In this study, the therapeutic potential of forsythoside B and its mechanism of action were investigated in a lipopolysaccharide (LPS)-induced ALI mouse model. The results showed that LPS-induced edema exudation and lung pathological changes in mice were significantly suppressed by forsythoside B pre-treatment. Furthermore, it also attenuated lung inflammation caused by LPS stimulation, evidenced by decreased inflammatory cell infiltration and down-regulated expression of cytokines, chemokines, and inducible enzymes. The anti-inflammation property of forsythoside B was confirmed in vitro using LPS-stimulated RAW 264.7 macrophages. Moreover, it alleviated LPS-induced inflammation by inhibiting the activation of TLR4/NF-κB signaling pathway in vivo and in vitro. In conclusion, the results demonstrated that forsythoside B protects against LPS-induced ALI by attenuating inflammatory cell infiltration and suppressing TLR4/NF-κB-mediated lung inflammation. Therefore, it might be a potential therapeutic agent for ALI caused by sepsis.     

Peroxiredoxin 1-mediated activation of TLR4/NF-κB pathway contributes to neuroinflammatory injury in intracerebral hemorrhage

The proinflammatory properties of extracellular peroxiredoxins (Prxs) via induction of Toll-like receptor 4 (TLR4) activation have been gradually revealed under diverse stress conditions, including cerebral ischemia but not hemorrhage. Prx1 is proposed to be a major hemorrhagic stress-inducible isoform of Prxs during acute and subacute phases of intracerebral hemorrhage (ICH). However, the potential of Prx1 in the neuroinflammatory injury after ICH remains unclear. This study investigated the proinflammatory effect and underlying mechanism of extracellular Prx1 in cultured murine macrophages and a collagenase-induced mouse ICH model. The current results show that incubation of exogenous Prx1 (0–50 nM) with murine RAW264.7 macrophages resulted in increased expression of TLR4, nuclear translocation of nuclear factor κB (NF-κB) p65 and production of proinflammatory mediators (NO, TNF-a and IL-6) in a concentration-dependent manner. In addition, ICH induced murine neurological deficits, cerebral edema and neuropathological alterations, such as neuron injury, astrocyte and microglia/macrophage activation, and neutrophil and T lymphocyte invasion up to 72 h after ICH. Moreover, ICH stimulated Prx1 expression and extracellular release, TLR4/NF-κB signaling activation, reflected by increases in TLR4 expression, extracellular signal-regulated kinase (ERK) 1/2 and NF-κB activation, and production of cytokines (TNF-α, IL-6 and IL-17). Taken together, these findings suggest that extracellular Prx1-mediated TLR4/NF-κB pathway activation probably contributes to neuroinflammatory injury after ICH, and thus blocking Prx1-TLR4 signaling might provide a novel anti-neuroinflammatory strategy with extended therapeutic window for hemorrhagic stroke.     

Diallyl-disulfide,an organosulfur compound of garlic,attenuates airway inflammation via activation of the Nrf-2/HO-1 pathway and NF-kappaB suppression

Diallyl disulfide (DADS) is a major organosulfur compound found in garlic oil that is widely used as a flavoring agent. In this study, we evaluated the effects of DADS on airway inflammation using an ovalbumin-induced model of allergic asthma and RAW264.7 cells. DADS decreased nitric oxide production with a reduction in the levels of interleukins (IL)-1β and IL-6 in RAW264.7 cells stimulated with LPS. DADS also reduced the expression of proinflammatory proteins including inducible nitric oxide synthase (iNOS), nuclear factor (NF)-κB, and matrix metalloproteinase (MMP)-9, and it enhanced the expression of antioxidant proteins including Nrf-2 and hemeoxygenase (HO)-1. In in vivo experiments, DADS decreased the inflammatory cell count in the bronchoalveolar lavage fluid (BALF) with IL-4, IL-5, IL-13, and immunoglobulin (Ig) E. These results were consistent with the histological analysis. DADS attenuated the airway inflammation and mucus hypersecretion induced by OVA challenge. In addition, DADS induced the activation of Nrf-2 and the expression of HO-1. In contrast, DADS reduced the activation of NF-κB, iNOS and MMP-9. In conclusion, DADS reduced the airway inflammation via regulation of Nrf-2/HO-1 and NF-κB. These results suggest that DADS might represent a useful new oral therapy to treat allergic asthma.     

Water extract of processed Hydrangea macrophylla (Thunb.) Ser. leaf attenuates the expression of pro-inflammatory mediators by suppressing Akt-mediated NF-κB activation

Although Hydrangea macrophylla is native to Northeast Asia and widely cultivated in many parts of the world, no studies on its anti-inflammatory effects have been reported. In this study, we evaluated the anti-inflammatory effect of a water extract of processed H. macrophylla leaf (WH) in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells. WH inhibited the expression of LPS-stimulated pro-inflammatory mediators such as nitric oxide (NO), prostaglandin E₂ (PGE₂), and tumor necrosis factor-α (TNF-α), as well as their regulatory genes inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), and TNF-α without any accompanying cytotoxicity. Moreover, WH significantly suppressed the LPS-induced DNA-binding activity of nuclear factor-κB (NF-κB), as well as the nuclear translocation of the NF-κB subunits, p65 and p50 by suppressing of IκBα phosphorylation and degradation. WH also increased Akt dephosphorylation, leading to the suppression of the DNA-binding activity of NF-κB in LPS-stimulated RAW264.7 macrophage cells. Our results indicate that WH downregulates the expression of pro-inflammatory mediators such as NO, PGE₂, and TNF-α by suppressing the Akt-mediated NF-κB activity in LPS-stimulated RAW264.7 macrophage cells.     

Britanin suppresses LPS-induced nitric oxide,PGE2 and cytokine production via NF-κB and MAPK inactivation in RAW 264.7 cells

Little is known about the biological properties of britanin, which is isolated from the flowers of Inula japonica (Inulae Flos). Based on our previous studies that Inulae Flos had anti-inflammation and anti-asthmatic activities, we tried to find the bioactive compounds from it. In this study, the anti-inflammatory effects of britanin on the inflammatory mediators as well as on nuclear factor (NF)-кB and mitogen-activated protein (MAP) kinase activation were evaluated in RAW 264.7 cells. Britanin inhibited the production of nitric oxide (NO) and prostaglandin E2 (PGE₂) along with the expression of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2 in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. In addition, britanin reduced the release of pro-inflammatory cytokines, such as TNF-α, IL-1β, and IL-6. Furthermore, the phosphorylations of MAP kinases (p38 and JNK) in LPS-stimulated RAW 264.7 cells were suppressed by britanin. Moreover, britanin inhibited the NF-κB activation induced by LPS, which was associated with the abrogation of IκBα degradation and subsequent decreases in nuclear p65 levels. This study suggests that the anti-inflammatory activities of britanin might be attributed to the inhibition of iNOS and COX-2 and cytokine expression at least in part, through the attenuation of the phosphorylations of MAP kinases and NF-κB activation via IκBα degradation in macrophages. We conclude that britanin may have potential for the treatment of inflammatory diseases through the down-regulation of MAP kinases and NF-κB mediated activation of macrophages.     

4-hydroxybenzo[d]oxazol-2(3H)-one ameliorates LPS/D-GalN-induced acute liver injury by inhibiting TLR4/NF-κB and MAPK signaling pathways in mice

The purpose of this study was to synthesize 4-hydroxybenzo[d]oxazol-2(3H)-one (HBO) and to investigate its protective effects on lipopolysaccharide (LPS)/D-galactosamine (D-GalN)-induced acute liver injury. HBO (C₇H₅O₃N) was synthesized based on 2-nitro-resorcinol and identified by physicochemical analysis. In the animal experiment, mice were pretreated with HBO (50, 100, 200 mg/kg) for 10 days. At the end of pretreatment, the animals were injected with LPS (10 µg/kg)/D-GalN (700 mg/kg). The results showed that HBO significantly alleviated liver injury induced by LPS/D-GalN in mice. It remarkably decreased inflammatory response by reducing the levels of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β). Moreover, HBO notably attenuated hepatocyte apoptosis by inhibiting the release of Cytochrome C (Cyt C) from mitochondria into the cytoplasm and regulating the expression of B-cell lymphoma-2 (Bcl-2) family. Furthermore, the result showed that HBO inhibited the expressions of nuclear factor kappa-B p50 (NF-κBp50), toll-like receptor 4 (TLR4), and myeloid differentiation factor 88 (MyD88), as well as the phosphorylation of inhibitor of nuclear factor kappa-B (IκB), inhibitor of nuclear factor kappa-B kinase-α/β (IKK-α/β), nuclear factor kappa-B p65 (NF-κBp65), suggesting that HBO had a certain influence on the TLR4/NF-κB pathway. In addition, the mitogen-activated protein kinase (MAPK) signaling pathway was also affected by HBO, as evidenced by the decrease in the phosphorylation levels of extracellular regulated protein kinase 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38). In conclusion, our study suggested that HBO could protect against LPS/D-GalN-induced liver injury, moreover, treatment with HBO appeared to be capable of further regulating the TLR4/NF-κB and MAPK signaling pathways.     

Secoisolariciresinol diglucoside suppresses Dextran sulfate sodium salt-induced colitis through inhibiting NLRP1 inflammasome

Inflammatory bowel disease (IBD) is a chronic and recurrent intestinal inflammatory disease with high risks for colorectal cancer and extremely affect people's health. Secoisolariciresinol diglucoside (SDG), a major component of lignans, exerts anti-inflammatory effects against digestive system diseases through a multi-target mechanism. However, the effect of SDG on IBD is not clear. In the present study, we aimed to investigate the effects of SDG on IBD and elucidate the underlying mechanism. The Dextran Sulfate Sodium Salt (DSS)-induced colitis model and lipopolysaccharide (LPS) stimulated RAW264.7 mouse macrophages cellular inflammation model were established. Morphological and pathological changes in colitis tissue in mice were observed by HE staining. Macrophage infiltration was detected by flow cytometry. The levels of nucleotide oligomerization domain-like receptor protein 1 (NLRP1) inflammasome complexes, nuclear factor-kappa B (NF-κB) and inflammatory cytokines were determined using quantitative real-time polymerase chain reaction, western blotting, and enzyme-linked immunosorbent assay. The results showed that SDG significantly attenuated the pathological severity and the number of macrophage infiltration of colitis in mice. Besides, SDG decreased the levels of inflammatory cytokines (IL-1β, IL-18 and TNF-α) and inhibited the activation of the NLRP1 inflammasome in DSS-induced colitis mice and RAW264.7 mouse macrophages. Moreover, the inhibitory effect of SDG was partly dependent on the disruption of NF-κB activation. Our results indicated that SDG relieves colitis by inhibiting NLRP1 inflammasome, and partly dependent on the disruption of NF-κB activation. Therefore, SDG may be a potential treatment option for IBD.     

Anemoside B4 prevents acute ulcerative colitis through inhibiting of TLR4/NF-κB/MAPK signaling pathway

Anemoside B4 (B4) is a compound extracted from Pulsatilla chinensis(P. chinensis). Pharmacological studies have proved that it has certain anti-inflammatory activity. Acute ulcerative colitis (ulcerative colitis) is a non-specific inflammatory disease whose pathogenesis is not completely known, and there is no effective drugs. The purpose of this study was to investigate the protective effect of B4 on ulcerative colitis and its mechanism. In this study, the C57BL/6 mice model of ulcerative colitis was established by DSS [3% (w/v)] and treated with intraperitoneal injection of B4 and oral administration of mesalazine, respectively. During the experiment, the clinical symptoms of the mice were scored by the disease activity index (DAI). Histopathological changes were observed by HE staining. In addition, the effect of LPS on Raw264.7 cells was also studied. In vivo studies showed that B4 could prevent DSS-induced colitis mice from losing weight, shortening colon length and improving pathological changes of colon tissues. B4 significantly reduced levels of inflammatory cytokines IL-1β, IL-6, and TNF-α in colon tissues. In vitro experiments, B4 was almost nontoxic to Raw264.7 cells and could protect the Raw264.7 cells induced by LPS. In terms of mechanism, B4 significantly inhibited the activation of the TLR4 signaling pathway induced by DSS and down-regulate the expression of key proteins in the TLR4/NF-κB/MAPK signaling pathway in Raw264.7 cells induced by LPS. These findings suggest that the inhibition of B4 on ulcerative colitis may be through the TLR4/NF-κB/MAPK pathway. Therefore, B4 may be used as a potential drug for the treatment of ulcerative colitis.     

Immunostimulatory activity of aqueous extract isolated from Prunella vulgaris

Prunella vulgaris (P. vulgaris) has been used as a traditional medicine in the clinical treatment of herpetic keratitis and for its antioxidative and antimicrobial activities. In this study, we examined the immunostimulatory and antitumor activity of P. vulgaris in murine macrophage RAW 264.7 cells. Thus, we investigated the effects of an aqueous extract of P. vulgaris (PVAE) on macrophage function. We found that PVAE stimulated macrophage phagocytic activity, nitric oxide (NO) production and cytostatic activity. In addition, PVAE induced gene expression and production of macrophage-related cytokines such as TNF-α, IL-1β and IL-6. Transient transfection revealed that NF-κB mediated the PVAE-induced increases in macrophage-related cytokine expression levels. Mitogen-activated protein kinases (MAP Kinase) were also significantly activated by the PVAE-induced NF-κB activation. Pretreatment with NF-κB inhibitor and MAP Kinase inhibitors inhibited the NO production and the phagocytic activity induced by PVAE. This demonstrates that PVAE stimulates macrophage activation via NF-κB transactivation and MAP kinase activation.     

Protective effects of morin on lipopolysaccharide/d-galactosamine-induced acute liver injury by inhibiting TLR4/NF-κB and activating Nrf2/HO-1 signaling pathways

Morin, a bioactive flavonoid extracted from the bark of Moraceae plants and many medicinal herbs, has anti-inflammatory and antioxidative effects. In this research, we explored the protective effects of morin against lipopolysaccharide (LPS) and d-galactosamine (D-GalN) induced acute liver injury in mice. Mice were given an intraperitoneal injection of morin before LPS and D-GalN treatment and the HepG2 cells were only given morin to investigate its effects. The results showed that morin markedly inhibited the production of serum alanine transaminase (ALT), aspartate aminotransferase (AST), interleukin-6 (IL-6), tumor necrosis factor (TNF-α) and hepatic TNF-α, IL-6, and myeloperoxidase (MPO) induced by LPS/D-GalN. In order to evaluate morin effect in the future, we investigated the expression of nuclear factor E2 related factor 2 (Nrf2), nuclear factor-kappaB (NF-κB), toll like receptor 4 (TLR4) on liver injury. Taken together, these results suggested that morin could exert the anti-inflammatory and anti-oxidative effects against LPS/D-GalN-induced acute liver injury by activating Nrf2 signal pathways and inhibiting NF-κB activation.     

Protective effects of probiotic Lactobacillus casei Zhang against endotoxin- and d-galactosamine-induced liver injury in rats via anti-oxidative and anti-inflammatory capacities

Lactobacillus casei Zhang (LcZ) has been recently isolated from the traditional Mongolian beverage koumiss and has a set of favorable probiotic properties, including aciduricity, bile resistance and ability to colonize the gastrointestinal tract. We have previously reported the anti-oxidative properties of LcZ in the hyperlipidemic rats. In this study, the hepatoprotective effects of LcZ against lipopolysaccharide (LPS) and d-galactosamine (D-GalN)-induced liver injury were investigated. We found that pretreatment with LcZ significantly improved survival of rats challenged with LPS/D-GalN. In addition, pretreatment with LcZ significantly decreased alanine transaminase (ALT) and aspartate aminotransferase (AST) levels in LPS/D-GalN-challenged rats, which were accompanied by diminished liver injuries, reduced malondialdehyde (MDA) content and increased superoxide dismutase (SOD) activity in liver homogenates. Pretreatment with LcZ also markedly reduced LPS/D-GalN-induced production of hepatic nitric oxide (NO), activation of inducible nitric oxide synthase (iNOS) and expression of tumor necrosis factor-α (TNF-α). Furthermore, hepatic toll-like receptor 4 (TLR4) mRNA and protein levels, the phosphorylation of I-κB and translocation of nuclear factor κB (NF-κB) were significantly down-regulated by pretreatment with LcZ. These results suggest that pretreatment with LcZ protects against LPS/D-GalN-induced liver injury in rats via its anti-oxidative and anti-inflammatory capacities. The hepatoprotective effects of LcZ are associated with an inhibition of TLR4 expression and TLR4 signaling.