Chikusetsusaponin V inhibits inflammatory responses via NF-κB and MAPK signaling pathways in LPS-induced RAW 264.7 macrophages

Excessive activation of macrophages is implicated in various inflammation resulted injuries. Saponins from Panax japonicus (SPJ) have been shown to possess anti-inflammatory activities. However, whether Chikusetsusaponin V (CsV), the most abundant component of SPJ, can exert anti-inflammatory activities is unknown. The present study was aimed to investigate the anti-inflammatory effects of CsV in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells and the underlying mechanisms. Our data showed that CsV dose-dependently inhibited NO, iNOS, TNF-α and IL-1β expressions in LPS-stimulated RAW264.7 cells. Increased protein levels of nuclear NF-κB and elevated phosphorylation levels of ERK and JNK in LPS-stimulated RAW 264.7 cells were also found downregulated by CsV treatment. Furthermore, the increase of CD14 and TLR4 mRNA expression due to LPS stimulation were significantly reversed by CsV treatment. These results suggested that CsV attenuated LPS-induced inflammatory responses partly via TLR4/CD14-mediated NF-κB and MAPK pathways.     

A novel fibrinogenase from Agkistrodon acutus venom protects against LPS-induced endotoxemia via regulating NF-κB pathway

Abstract

Context: Endotoxins including lipopolysaccharide (LPS) could cause endotoxemia which often results in excessive inflammation, organ dysfunction, sepsis, disseminated intravascular coagulation (DIC) or even death. Previously, a novel fibrinogenase (FII) showed protective effects on LPS-induced DIC via activating protein C and suppressing inflammatory cytokines.

Objective: To evaluate whether FII has protective effect on LPS-induced endotoxemia in mice and learn about the role of NF-κB pathway in TNF-α producing process.

Methods: BALB/C mice were intraperitoneally injected (i.p.) with (a) 30?mg/kg LPS, (b) LPS?+?0.3?mg/kg FII, (c) LPS?+?1.0?mg/kg FII, (d) LPS?+?3.0?mg/kg FII or (e) saline. Both survival rate and organ function were tested, including alanine aminotransferase (ALT), blood urine nitrogen (BUN) and tissue section, and TNF-α was examined by ELISA. RAW 264.7 macrophage was administered with (a) LPS, (b) LPS?+?FII, (c) FII alone or (d) saline, and TNF-α and phosphorylation (P)-NF-κB (P65) were determined by Western blot.

Results: The administration of LPS led to 65% mortality rate, a rise of serum TNF-α, BUN and ALT levels, and both liver and renal tissue damage were observed. While FII treatment significantly increased the survival rate of LPS-induced endotoxemia mice model, histopathology and protein analysis results also revealed that FII remarkably protected liver and renal from LPS damage as well as decreasing TNF-α level. In vitro, FII significantly decreased LPS-induced TNF-α production and the expression of P-NF-κB (P65).

Conclusions: Our findings suggested that FII had protective effect on LPS-induced endotoxemia and organ injuries by suppressing the activation of NF-κB which decreased TNF-α level.     

Licochalcone A Attenuates Lipopolysaccharide-Induced Acute Kidney Injury by Inhibiting NF-κB Activation

Licochalcone A (Lico A), a flavonoid found in licorice root (Glycyrrhiza glabra), has been reported to have anti-inflammatory activity. However, the protective effects of Lico A on lipopolysaccharide (LPS)-induced acute kidney injury (AKI) remains unclear. In this study, using a mouse model of LPS-induced AKI, we investigated the protective effects and mechanism of Lico A on LPS-induced AKI in mice. LPS-induced kidney injury was assessed by detecting kidney histological study, blood urea nitrogen (BUN), and creatinine levels. The production of inflammatory cytokines TNF-α, IL-6, and IL-1β in serum and kidney tissues was detected by ELISA. The activation of NF-κB was measured by western blot analysis. Our results showed that Lico A dose-dependently attenuated LPS-induced kidney histopathologic changes, serum BUN, and creatinine levels. Lico A also suppressed LPS-induced TNF-α, IL-6, and IL-1β production both in serum and kidney tissues. Furthermore, our results showed that Lico A significantly inhibited LPS-induced NF-κB activation. In conclusion, our results suggest that Lico A has protective effects against LPS-induced AKI and Lico A exhibits its anti-inflammatory effects through inhibiting LPS-induced NF-κB activation.     

Inhibition of PKR ameliorates lipopolysaccharide-induced acute lung injury by suppressing NF-κB pathway in mice

Acute lung injury (ALI) is characterized by dramatic lung inflammation and alveolar epithelial cell death. Although protein kinase R (PKR) (double-stranded RNA-activated serine/threonine kinase) has been implicated in inflammatory response to bacterial cell wall components, whether it plays roles in lipopolysaccharide (LPS)-induced ALI remains unclear. This study was aimed to reveal whether and how PKR was involved in LPS-induced ALI pathology and the potential effects of its specific inhibitor, C16 (C₁₃H₈N₄OS). During the experiment, mice received C16 (100 or 500 ug/kg) intraperitoneally 1?h before intratracheal LPS instillation. Then, whole lung lavage was collected for analysis of total protein levels and proinflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and IL-6. The lungs were tested for Western blot, transferase-mediated dUTP nick-end labeling (TUNEL) stain and immunohistochemistry. Results showed that PKR phosphorylation increased significantly after LPS instillation. Furthermore, PKR specific inhibition attenuated LPS-induced lung injury (hematoxylin and eosin stain), reduced lung protein permeability (total protein levels in whole lung lavage) and suppressed proinflammatory cytokines (TNF-α, IL-1β and IL-6) and lung apoptosis (TUNEL stain and caspase3 activation). Moreover, mechanism-study showed that C16 significantly suppressed I kappa B kinase (IKK)/I kappa B alpha (IκBα)/NF-κB signaling pathway after LPS challenge. These findings suggested that PKR inhibition ameliorated LPS-induced lung inflammation and apoptosis in mice by suppressing NF-κB signaling pathway.     

Cepharanthine, an Alkaloid from Stephania cepharantha Hayata, Inhibits the Inflammatory Response in the RAW264.7 Cell and Mouse Models

The aim of this study was to investigate the protective effects of cepharanthine (CEP) on inflammation in lipopolysaccharide (LPS)-stimulated RAW264.7 cells in vitro and a LPS-induced lung injury model in vivo. RAW264.7 cells were treated with various concentrations of CEP for 1 h followed by incubation with or without 1 μg/ml LPS for 18 h. TNF-α, IL-6, and IL-1β in the supernatants were measured by ELISA. Nuclear factor-κB (NF-κB) and mitogen-activated protein kinase pathways were analyzed by Western blot. Mice were randomly divided into control group, LPS group, CEP?+?LPS group, and dexamethasone?+?LPS group. A male BALB/c mouse model of acute lung injury was induced by LPS. Bronchoalveolar lavage fluid was collected for inflammatory cell count and cytokine assays. Histopathologic examination was performed on mice that were not subjected to bronchoalveolar lavage fluid collection. CEP dose-dependently inhibited the release of TNF-α, IL-6, and IL-1β in LPS-stimulated RAW264.7 cells. Significantly, CEP dose-dependently suppressed NF-κB activation, IκBα degradation, and phosphorylation of ERK, JNK, and p38 induced by LPS. In vivo, it was also observed that CEP attenuated lung histopathologic changes and down-regulated the level of pro-inflammatory cytokines, including TNF-α, IL-1β, and IL-6, in the mouse acute lung injury model. These results suggest that CEP potentially decreases inflammation in vitro and in vivo and might be a therapeutic agent against inflammatory diseases.     

Protective effect of gossypol on lipopolysaccharide-induced acute lung injury in mice

Objective

Gossypol has been reported to have anti-inflammatory properties. The purpose of this study was to evaluate the effect of gossypol on acute lung injury (ALI) induced by lipopolysaccharide (LPS) in mice.

Methods

Male BALB/c mice were pretreated with gossypol 1 h before intranasal instillation of LPS. Then, 7 h after LPS administration, the myeloperoxidase in histology of lungs, lung wet/dry ratio and inflammatory cells in the bronchoalveolar lavage fluid (BALF) were determined. The levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) in the BALF were measured by ELISA. The extent of phosphorylation of IκB-α, p65 NF-κB, p46–p54 JNK, p42–p44 ERK, and p38 were detected by western blot.

Results

Gossypol markedly attenuated the LPS-induced histological alterations in the lung and inhibited the production of TNF-α, IL-1β and IL-6. Additionally, gossypol reduced the inflammatory cells in BALF, decreased the wet/dry ratio of lungs and inhibited the phosphorylation of IκB-α, p65 NF-κB, p46–p54 JNK, p42–p44 ERK, and p38 caused by LPS.

Conclusion

The data suggest that anti-inflammatory effects of gossypol against the LPS-induced ALI may be due to its ability of inhibition of the NF-κB and MAPKs signaling pathways. Gossypol may be a promising potential therapeutic reagent for ALI treatment.     

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.     

p-Cymene Modulates In Vitro and In Vivo Cytokine Production by Inhibiting MAPK and NF-κB Activation

The present study was designed to investigate the effects of p-cymene on lipopolysaccharide (LPS)-induced inflammatory cytokine production both in vitro and in vivo. The production of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and interleukin-10 (IL-10) in LPS-stimulated RAW 264.7 cells and C57BL/6 mice was evaluated by sandwich ELISA. Meanwhile, the mRNA levels of cytokine genes were examined in vitro by semiquantitative RT-PCR. In a further study, we analyzed the activation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways by western blotting. We found that p-cymene significantly regulated TNF-α, IL-1β, and IL-6 production in LPS-stimulated RAW 264.7 cells. Furthermore, the levels of relative mRNAs were also found to be downregulated. In in vivo trail, p-cymene markedly suppressed the production of TNF-α and IL-1β and increased IL-10 secretion. We also found that p-cymene inhibited LPS-induced activation of extracellular signal receptor-activated kinase 1/2, p38, c-Jun N-terminal kinase, and IκBα. These results suggest that p-cymene may have a potential anti-inflammatory action on cytokine production by blocking NF-κB and MAPK signaling pathways.     

Resveratrol protects BV2 mouse microglial cells against LPS-induced inflammatory injury by altering the miR-146a-5p/TRAF6/NF-κB axis

Abstract

Objective: To investigate the role of miR-146a-5p in the effects of resveratrol (RSV) on inflammatory response in BV2 mouse microglial cells.

Materials and methods: BV2 cells were pretreated by RSV and stimulated with lipopolysaccharide (LPS). Cell Viability was checked using a MTT assay. Real-Time PCR was performed to detect the levels of pro-inflammatory cytokines (tumor necrosisfactor-α－TNF-α, interleukin-1β－IL-1β and interleukin-6 － IL-6) and miR-146a-5p expression. Western blot was used to analyze the protein expression of TNF receptor associated factor 6 (TRAF6) and phospho-nuclear factor kappa B (pNF-κB). Gain-of-function and loss-of-function analysis of miR-146a-5p was performed using transfection of miR-146a-5p mimic and miR-146a-5p inhibitor, respectively.

Results: Pretreatment with RSV significantly and dose dependently inhibited LPS-induced production of TNF-α, IL-1β and IL-6 in BV2 cells. MiR-146a-5p was significantly upregulated after LPS treatment, and further increased in RSV and LPS-co-treated cells. MiR-146a-5p overexpression via miR-146a-5p mimic transfection downregulated the mRNA level of TNF-α, IL-1β and IL-6, as well as abrogated the protein expression of TRAF6 and pNF-κB in BV2 cells exposed to LPS. More importantly, the reducion of TNF-α, IL-1β and IL-6 level by RSV were reversed by miR-146a-5p silence via miR-146a-5p inhibitor transfection. Furthermore, silencing miR-146a-5p attenuated the inhibitory effect of RSV on the TRAF6/NF-κB pathway which was activated after induction with LPS. Conclusions: RSV can suppress LPS-induced inflammatory injury via modulating the miR-146a-5p/TRAF6/NF-κB axis in BV2 mouse microglial cells.     

罗哌卡因通过 HMGB1 / NF-κB 通路减轻 LPS 诱导的小鼠急性 肺损伤

目的 探讨罗哌卡因 ( ropivacaine, Rop) 对脂多糖 ( lipopolysaccharide, LPS) 诱导的小鼠急性 肺损伤 (acute lung injury, ALI) 的作用及其机制。 方法 气管内滴注 LPS 诱导肺损伤小鼠模型, 并将小鼠 随机分为 6 组: 对照组、 LPS 组、 罗哌卡因 0. 25、 0. 5、 1 μmol / L 组和右美托咪定 (dexmedetomidine, Dex) 100 μg / kg 组。 Hematoxylin-eosin (H&E) 染色评估肺组织的组织病理学变化; ELISA 法测定肺组织中髓过 氧化物酶 (myeloperoxidase, MPO)、 丙二醛 ( malondialdehyde, MDA)、 超氧化物歧化酶 ( superoxide dismutase, SOD) 和谷胱甘肽过氧化物酶 ( glutathione peroxidase, GSH-Px) 的活性; 检测血清中 IL-6、 IL-1β 和肿瘤坏死因子-α (tumor necrosis factor-α, TNF-α) 的表达; Western 印迹检测 HMGB1 / NF-κB 通路相关蛋 白的表达。 结果 与对照组比较, LPS 诱导肺泡外膜增厚、 出血和肺水肿; 肺损伤评分和肺含水量增加; MPO 和 MDA 活性增加, SOD 和 GSH-Px 水平降低; IL-6、 IL-1β 和 TNF-α 水平升高; HMGB1 蛋白和 NF-κB P65 磷酸化水平升高, 有显著性差异 (P< 0. 05)。 与 LPS 组比较, 罗哌卡因 0. 5、 1 μmol / L 组小鼠肺损伤 程度明显减轻; MPO 和 MDA 活性降低, SOD 和 GSH-Px 水平升高; IL-6、 IL-1β 和 TNF-α 水平降低; HMGB1 蛋白和 NF-κB P65 磷酸化水平降低, 有显著性差异 (P< 0. 05)。 结论 罗哌卡因通过抑制 HMGB1 / NF-κB 通路, 有效减弱了 LPS 引起的肺组织损伤。     

Plumbagin,a Vitamin K3 Analogue,abrogates Lipopolysaccharide-Induced Oxidative Stress,Inflammation and Endotoxic Shock via NF-κB Suppression

Plumbagin has been reported to modulate cellular redox status and suppress NF-κB. In the present study, we investigated the effect of plumbagin on lipopolysaccharide (LPS)-induced endotoxic shock, oxidative stress and inflammatory parameters in vitro and in vivo. Plumbagin inhibited LPS-induced nitric oxide, TNF-α, IL-6 and prostaglandin-E2 production in a concentration-dependent manner in RAW 264.7 cells without inducing any cell death. Plumbagin modulated cellular redox status in RAW cells. Plumbagin treatment significantly reduced MAPkinase and NF-κB activation in macrophages. Plumbagin prevented mice from endotoxic shock-associated mortality and decreased serum levels of pro-inflammatory markers. Plumbagin administration ameliorated LPS-induced oxidative stress in peritoneal macrophages and splenocytes. Plumbagin also attenuated endotoxic shock-associated changes in liver and lung histopathology and decreased the activation of ERK and NF-κB in liver. These findings demonstrate the efficacy of plumbagin in preventing LPS-induced endotoxemia and also provide mechanistic insights into the anti-inflammatory effects of plumbagin.     

Anti-inflammatory Role of Pilose Antler Peptide in LPS-Induced Lung Injury

The present study was designed to investigate the effects of pilose antler peptide (PAP) on lipopolysaccharide (LPS)-induced lung injury. BalB/c mice intraperitoneally received PAP (10 and 20 mg/kg) or dexamethasone (2 mg/kg) 1 h prior to intratracheal instillation of LPS. PAP significantly decreased lung wet-to-dry weight (W/D) ratio and lung myeloperoxidase (MPO) activity and restored LPS-induced lung histopathological changes. PAP also increased super oxide dismutase (SOD) level and inhibited malondialdehyde (MDA) content and levels of pro-inflammatory cytokines including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) in bronchoalveolar lavage fluid (BALF) in LPS-stimulated mice. Furthermore, we demonstrated that PAP inhibited Rho/NF-κB pathway in LPS-induced mice. Our experimental results indicated that the protective mechanism of PAP might be attributed partly to the inhibition of Rho/NF-κB pathway.     

Glycogen synthase kinase-3β inactivation inhibits tumor necrosis factor-α production in microglia by modulating nuclear factor κB and MLK3/JNK signaling cascades

Background

Deciphering the mechanisms that modulate the inflammatory response induced by microglial activation not only improves our insight into neuroinflammation but also provides avenues for designing novel therapies that could halt inflammation-induced neuronal degeneration. Decreasing glycogen synthase kinase-3β (GSK-3β) activity has therapeutic benefits in inflammatory diseases. However, the exact molecular mechanisms underlying GSK-3β inactivation-mediated suppression of the inflammatory response induced by microglial activation have not been completely clarified. Tumor necrosis factor-α (TNF-α) plays a central role in injury caused by neuroinflammation. We investigated the regulatory effect of GSK-3β on TNF-α production by microglia to discern the molecular mechanisms of this modulation.

Methods

Lipopolysaccharide (LPS) was used to induce an inflammatory response in cultured primary microglia or murine BV-2 microglial cells. Release of TNF-α was measured by ELISA. Signaling molecules were analyzed by western blotting, and activation of NF-κB and AP-1 was measured by ELISA-based DNA binding analysis and luciferase reporter assay. Protein interaction was examined by coimmunoprecipitation.

Results

Inhibition of GSK-3β by selective GSK-3β inhibitors or by RNA interference attenuated LPS-induced TNF-α production in cultured microglia. Exploration of the mechanisms by which GSK-3β positively regulates inflammatory response showed that LPS-induced IκB-α degradation, NF-κBp65 nuclear translocation, and p65 DNA binding activity were not affected by inhibition of GSK-3β activity. However, GSK-3β inactivation inhibited transactivation activity of p65 by deacetylating p65 at lysine 310. Furthermore, we also demonstrated a functional interaction between mixed lineage kinase 3 (MLK3) and GSK-3β during LPS-induced TNF-α production in microglia. The phosphorylated levels of MLK3, MKK4, and JNK were increased upon LPS treatment. Decreasing GSK-3β activity blocked MLK3 signaling cascades through disruption of MLK3 dimerization-induced autophosphorylation, ultimately leading to a decrease in TNF-α secretion.

Conclusion

These results suggest that inactivation of GSK-3β might represent a potential strategy to downregulate microglia-mediated inflammatory processes.

     

Apigenin exhibits anti-inflammatory effects in LPS-stimulated BV2 microglia through activating GSK3β/Nrf2 signaling pathway

Abstract

Objective: Apigenin is a natural flavonoid compound extracted from Matricaria chamomilla. We evaluated the anti-inflammatory effects of apigenin in this study using the Lipopolysaccharide (LPS)-stimulated BV2 microglia.

Methods: BV2 cells were treated with apigenin for 1?h and then treated with LPS. The inflammatory cytokine productions were tested by qRT-PCR and ELISA. The expression of GSK3β, Nrf2, and NF-κB signaling pathways were measured by western blot analysis.

Results: Apigenin significantly attenuated LPS-induced TNF-α, IL-1β, and IL-6 production. Apigenin suppressed LPS-induced NF-κB activation. Furthermore, GSK3β, Nrf2, and HO-1 were concentration-dependently increased by apigenin. The suppression of apigenin on LPS-induced inflammatory response and NF-κB activation were prevented when Nrf2 was knocked out or by GSK3β inhibitor.

Conclusions: Collectively, apigenin suppressed LPS-induced microglia activation via activating GSK3β/Nrf2 signaling pathway.     

Ellagic acid protects against LPS-induced acute lung injury through inhibition of nuclear factor kappa B,proinflammatory cytokines and enhancement of interleukin-10

Ellagic acid is a naturally occurring polyphenolic compound which is found in many fruits, nut galls and plant extracts. In the present study, we explored the ability of ellagic acid to modulate lipopolysaccharides (LPS) response using macrophage-mediated inflammatory conditions and acute lung injury (ALI). The data showed that ellagic acid reduced TNF-α, IL-6 and IL-1β secretions, enhance IL-10 production by LPS-stimulated RAW 264.7 macrophages in vitro. In murine ALI model, mice were treated with ellagic acid prior to LPS challenge. The data showed that ellagic acid possess a protective effect on LPS-induced ALI in mice. The underlying mechanism may be through shocking the NF-κB pathway to attenuate the nonspecific pulmonary inflammation induced by LPS administration.     

Cavidine Ameliorates Lipopolysaccharide-Induced Acute Lung Injury <Emphasis Type="Italic">via</Emphasis> NF-κB Signaling Pathway <Emphasis Type="Italic">in vivo</Emphasis> and <Emphasis Type="Italic">in vitro</Emphasis>

Acute lung injury (ALI) is characterized by widespread inflammation in the lungs and alveolar-capillary destruction, causing high morbidity and mortality. Cavidine, isolated from Corydalis impatiens, have been exhibited to have potent anti-inflammatory effects in previous studies. The purpose of this study was to evaluate the protective effect of cavidine on lipopolysaccharide (LPS)-induced ALI and to enunciate the underlying in vivo and in vitro mechanisms. Mice were intraperitoneally administrated with cavidine (1, 3, or 10 mg/kg) at 1 and 12 h, prior to the induction of ALI by intranasal administration of LPS (30 mg/kg). Blood samples, lung tissues, and bronchoalveolar lavage fluid (BALF) were harvested after LPS challenge. Furthermore, we used LPS-induced lung epithelial cells A549 to examine the mechanism of cavidine to lung injury. The results showed that pretreatment with cavidine significantly decreased lung wet-to-dry weight (W/D) ratio, reduced pro-inflammatory cytokine levels including TNF-α and IL-6 in BALF and serum from LPS-stimulated mice, and attenuated lung histopathological changes. In addition, western blot results showed that cavidine inhibited the phosphorylation of nuclear factor-kappaB (NF-κB) p65 and IκBα induced by LPS. In conclusion, our results demonstrate that cavidine protects against LPS-induced acute lung injury in mice via inhibiting of pro-inflammatory cytokine TNF-α and IL-6 production and NF-κB signaling pathway activation. Taken together, cavidine may be useful for the prevention and treatment of pulmonary inflammatory diseases, such as ALI.     

Cytoprotection of Perfluorocarbon on PMVECs In Vitro

Lipopolysaccharide (LPS) can activate endothelial cells and induce inflammatory injury. Toll-like receptor-4 (TLR-4) is integrally involved in LPS signaling and has a requisite role in the activation of nuclear factor (NF)-κB. A number of studies have demonstrated the cytoprotective action of perfluorocarbon (PFC) both in vivo and in vitro, but the exact mechanisms have yet to be elucidated. In this study, we examined in an in vitro model the cytoprotective effect of PFC on LPS-stimulated pulmonary vascular endothelial cells (PMVECs). Intercellular adhesion molecule-1 (ICAM-1), tumor necrosis factor-α (TNF-α), and interleukin-8 (IL-8) were significantly increased in the LPS-stimulated PMVECs groups. The expression of TLR-4 mRNA and protein in LPS groups was markedly increased. Meanwhile, NF-κB was activated. There were no significant effects of PFC alone on any of the factors studied while the coculture group showed significant downregulation of the secretion of ICAM-1, TNF-α, and IL-8; the expression of TLR-4 mRNA; and the activity of NF-κB. LPS can induce PMVEC inflammatory injury via the activation of TLR-4 and subsequent activation of NF-κB. PFC is able to protect PMVECs from LPS-induced inflammatory injury by blocking the initiation of the LPS signaling pathway.     

Protective effect of astragaloside IV on lipopolysaccharide-induced cardiac dysfunction via downregulation of inflammatory signaling in mice

Abstract

Context: Astragaloside IV (ASI) is a major and active saponin derivative of Astragalus membranaceus (Fisch) Bge. The anti-inflammatory properties of ASI are important for its cardioprotective effects. However, the molecular mechanisms of the protective effect of ASI on lipopolysaccharide (LPS)-induced cardiac dysfunction is yet to be elucidated.

Objective: This study was designed to investigate the therapeutic effects and possible mechanisms of ASI against LPS-induced septic cardiac dysfunction and inflammation in mice.

Materials and methods: Mice were intraperitoneally injected with ASI (20?mg/kg) for 1 week before LPS challenge (10?mg/kg, i.p.). Left ventricular performance and morphology were analyzed using echocardiography 6?h after LPS induction. Activities of lactate dehydrogenase (LDH) in serum were measured and serum levels of cardiac troponin I (cTnI) were quantified by ELISA. Serum levels of tumor necrosis factor-α (TNF-α), monocyte chemotactic protein 1 (MCP-1), interleukin-6 (IL-6) and IL-1β were also quantified by ELISA. The protein expressions of NF-кB p65 and p-AKT in heart tissues were detected using Western blot analysis.

Results: LPS administration deteriorated cardiac function and was attenuated by ASI pretreatment. ASI attenuated LPS-induced the increase of LDH and cTnI activities in mice. ASI also prevented NF-кB activation and subsequent myocardial inflammatory responses in endotoxemic mice. The effects of ASI were closely associated with the phosphatidylinositol-3-kinase (PI3K/AKT) signaling pathway, as characterized by ASI-induced activation in phospho-Akt. ASI also extended the lifespan of toxemic mice.

Conclusion: ASI significantly attenuated LPS-induced cardiac dysfunction and inflammatory mediator production by inhibiting NF-кB and activating PI3K/AKT signaling pathway.