Kaempferol regulates MAPKs and NF-κB signaling pathways to attenuate LPS-induced acute lung injury in mice

Recent studies show that mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-κB) signaling pathways are two pivotal roles contributing to the development of lipopolysaccharide (LPS)-induced acute lung injury (ALI). The present study aimed to investigate the protective effect of kaempferol (Kae), a naturally occurring flavonoid compound, on ALI and explore its possible mechanisms. Male BALB/c mice with ALI, induced by intranasal instillation of LPS, were treated or not with Kae (100mg/kg, intragastrically) 1h prior to LPS exposure. Kae treatment attenuated pulmonary edema of mice with ALI after LPS challenge, as it markedly decreased the lung W/D ratio of lung samples, protein concentration and the amounts of inflammatory cells in BALF. Similarly, LPS mediated overproduction of proinflammatory cytokines in BALF, including TNF-α, IL-1β and IL-6, was strongly reduced by Kae. Histological studies demonstrated that Kae substantially inhibited LPS-induced alveolar wall thickness, alveolar hemorrhage and leukocytes infiltration in lung tissue with evidence of reduced myeloperoxidase (MPO) activity. Kae also efficiently increased superoxide dismutase (SOD) activity of lung sample when compared with LPS group, which was obviously reduced by LPS administration. In addition, Western blot analysis indicated that the activation of MAPKs and NF-κB signaling pathways stimulated by LPS was significantly blocked by Kae. Taken together, our results suggest that Kae exhibits a protective effect on LPS-induced ALI via suppression of MAPKs and NF-κB signaling pathways, which may involve the inhibition of tissue oxidative injury and pulmonary inflammatory process.     

Genipin alleviates LPS-induced acute lung injury by inhibiting NF-κB and NLRP3 signaling pathways

Genipin has been reported to have anti-inflammatory effect. However, its role on lipopolysaccharide (LPS)-induced acute lung injury (ALI) has not been explored. This study aimed to evaluate the effect of genipin on murine model of acute lung injury induced by LPS. The mice were treated with genipin 1 h before LPS administration. 12 h later, the myeloperoxidase (MPO) in lung tissues and lung wet/dry ratio were detected. The levels of TNF-α, IL-1β and IL-6 in bronchoalveolar lavage fluid (BALF) were measured by ELISA. Apart from this, we use western blot to detect the protein expression in the NF-κB and NLRP3 signaling pathways. The results showed that the treatment of genipin markedly attenuated the lung wet/dry ratio and the MPO activity. Moreover, it also inhibited the levels of TNF-α, IL-1β, IL-6 in the BALF. In addition, genipin significantly inhibited LPS-induced NF-κB and NLRP3 activation. In conclusion, these results demonstrate that genipin protected against LPS-induced ALI through inhibiting NF-κB and NLRP3 signaling pathways.     

Therapeutic effect of methyl salicylate 2-O-β-d-lactoside on LPS-induced acute lung injury by inhibiting TAK1/NF-kappaB phosphorylation and NLRP3 expression

Acute lung injury (ALI), characterized by pulmonary edema and inflammatory cell infiltration, is a common syndrome of acute hypoxemic respiratory failure. Methyl salicylate 2-O-β-d-lactoside (MSL), a natural derivative of salicylate extracted from Gaultheria yunnanensis (Franch.) Rehder, was reported to have potent anti-inflammatory effects on the progression of collagen or adjuvant-induced arthritis in vivo and in vitro. The aim of this study is to investigate the therapeutic effect of MSL on lipopolysaccharide (LPS)-induced acute lung injury and reveal underlying molecular mechanisms. Our results showed that MSL significantly ameliorated pulmonary edema and histological severities, and inhibited IL-6 and IL-1β production in LPS-induced ALI mice. MSL also reduced MPO activity in lung tissues and the number of inflammatory cells in BALF. Moreover, we found that MSL significantly inhibited LPS-induced TAK1 and NF-κB p65 phosphorylation, as well as the expression of NLRP3 protein in lung tissues. Furthermore, MSL significantly inhibited LPS-induced TAK1 and NF-κB p65 phosphorylation in Raw264.7 cells. In addition, MSL significantly inhibited nuclear translocation of NF-κB p65 in cells treated with LPS in vitro. Taken together, our results suggested that MSL exhibited a therapeutic effect on LPS-induced ALI by inhibiting TAK1/NF-κB phosphorylation and NLRP3 expression.     

Protective effect of taraxasterol on acute lung injury induced by lipopolysaccharide in mice

Taraxasterol, a pentacyclic-triterpene isolated from Taraxacum officinale, has been reported to have potent anti-inflammatory properties. However, the effect of taraxasterol on lipopolysaccharide (LPS)-induced mice acute lung injury has not been investigated. The aims of this study were to investigate whether taraxasterol could ameliorate the inflammation response in LPS-induced acute lung injury and to clarify the possible mechanism. Male BALB/c mice were pretreated with taraxasterol 1 h before intranasal instillation of LPS. 7 h after LPS administration, the myeloperoxidase (MPO) in lung tissues, lung wet/dry ratio and inflammatory cells in the bronchoalveolar lavage fluid (BALF) were detected. The levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), 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 determined by western blotting. The results showed that taraxasterol attenuated the infiltration of inflammatory cells, the activity of myeloperoxidase (MPO), lung wet/dry ratio, and the expression of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) in a dose-dependent manner. Additionally, western blotting results showed that taraxasterol inhibited the phosphorylation of IκB-α, p65 NF-κB, p46–p54 JNK, p42–p44 ERK, and p38 caused by LPS. Our data suggest that anti-inflammatory effects of taraxasterol against the LPS-induced ALI may be due to its ability of inhibition of the NF-κB and MAPK signaling pathways.     

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

Catalpol, an iridiod glucoside isolated from Rehmannia glutinosa, has been reported to have anti-inflammatory properties. Although anti-inflammatory activity of catalpol already reported, its involvement in lung protection has not been reported. Thus, we investigated the role of catalpol on lipopolysaccharide (LPS)-induced acute lung injury in this study. Mice acute lung injury model was induced by intranasal instillation of LPS. Catalpol was administrated 1 h prior to or after LPS exposure. The severity of pulmonary injury was evaluated 12 h after LPS administration. The results showed that catalpol inhibited lung W/D ratio, myeloperoxidase activity of lung samples, the amounts of inflammatory cells and TNF-α, IL-6, IL-4 and IL-1β in BALF induced by LPS. The production of IL-10 in BALF was up-regulated by catalpol. In vitro, catalpol inhibited TNF-α, IL-6, IL-4 and IL-1β production and up-regulated IL-10 expression in LPS-stimulated alveolar macrophages. Moreover, western blot analysis showed that the activation of NF-κB and MAPK signaling pathways was inhibited by catalpol. Furthermore, catalpol was found to inhibit TLR4 expression induced by LPS. In conclusion, catalpol potently protected against LPS-induced ALI. The protective effect may attribute to the inhibition of TLR4-mediated NF-κB and MAPK signaling pathways.     

Rapamycin ameliorates lipopolysaccharide-induced acute lung injury by inhibiting IL-1β and IL-18 production

Interleukin (IL)-1β and IL-18 play central and detrimental roles in the development of acute lung injury (ALI), and mammalian target of rapamycin (mTOR) is involved in regulating IL-1β and IL-18 production. However, it is not clear whether the mTOR specific inhibitor rapamycin can attenuate lipopolysaccharide (LPS)-induced ALI by modulating IL-1β and IL-18 production. In this study, we found that rapamycin ameliorated LPS-induced ALI by inhibiting NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome-mediated IL-1β and IL-18 secretion. Mechanistically, elevated autophagy and decreased nuclear factor (NF)-κB activation were associated with downregulated IL-1β and IL-18. Moreover, rapamycin reduced leukocyte infiltration in the lung tissue and bronchoalveolar lavage fluid (BALF), and contributed to the alleviation of LPS-induced ALI. Consistently, rapamycin also significantly inhibited IL-1β and IL-18 production by RAW264.7 cells via increased autophagy and decreased NF-κB signaling in vitro. Our results demonstrated that rapamycin protects mice against LPS-induced ALI partly by inhibiting the production and secretion of IL-1β and IL-18. mTOR and rapamycin might represent an appropriate therapeutic target and strategy for preventing ALI induced by LPS.     

NecroX-5 alleviate lipopolysaccharide-induced acute respiratory distress syndrome by inhibiting TXNIP/NLRP3 and NF-κB

The activation of NLRP3 inflammasome and NF-κB pathway, associating with oxidative stress, have been implicated in the development of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). NecroX-5 has been reported to exhibit the effects of anti-oxidation and anti-stress in various diseases. However, the role of NecroX-5 in ALI has not been explicitly demonstrated. The aim of this study was to explore the therapeutic effects and potential mechanism action of NecroX-5 on ALI. Here, we found that NecroX-5 pretreatment dramatically diminished the levels of IL-1β, IL-18 and ROS in in RAW264.7 cells challenged with LPS and ATP. Furthermore, NecroX-5 suppressed the activation of NLRP3 inflammasome and NF-κB signal pathway. In addition, NecroX-5 also inhibited the thioredoxin-interacting protein (TXNIP) expression. In vivo, NecroX-5 reduced the LPS-induced lung histopathological injury, the number of TUNEL-positive cells, lung wet/dry (W/D) ratio, levels of total protein and inflammatory cytokines in the bronchoalveolar lavage fluid (BALF) in mice. Additionally, LPS-induced upregulation of myeloperoxidase (MPO), ROS production and malondialdehyde (MDA) were inhibited by NecroX-5 administration. Thus, our results demonstrate that NecroX-5 protects against LPS-induced ALI by inhibiting TXNIP/NLRP3 and NF-κB.     

β-Patchoulene from patchouli oil protects against LPS-induced acute lung injury via suppressing NF-κB and activating Nrf2 pathways

β-Patchoulene (β-PAE), a tricyclic sesquiterpene isolated from the essential oil of the leaves and stems of Pogostemon cablin (Blanco) Benth., has been reported to have potent anti-inflammatory activity. The aim of this study was to evaluate the potential protective effect of β-PAE on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice and to illuminate the underlying mechanisms. ALI was induced by intracheal instillation of LPS into lung, and dexamethasone (DEX) was used as a positive control. Results indicated that pretreatment with β-PAE significantly decreased the mortality rate of mice and lung W/D weight ratio, ameliorated lung pathological changes as compared to model group. Meanwhile, β-PAE pretreatment markedly inhibited the increase of TNF-α, IL-6 and IL-1β secretions in the bronchoalveolar lavage fluid, and prevented LPS-induced elevations of MPO activity and MDA level in the lung. Additionally, β-PAE pretreatment significantly elevated miR-146a expression and suppressed the LPS-induced activation of NF-κB and expression of its mediated genes (TNF-α, IL-6 and IL-1β). β-PAE was also observed to markedly upregulate the Nrf2 and HO-1 expression and activate the antioxidant genes (NQO-1, GCLC and HO-1). Taken together, β-PAE possessed protective effect against LPS-induced ALI, which might be associated with its differential regulation of NF-κB and Nrf2 activities and up-regulation of expression of miR-146a. The results rendered β-PAE a promising anti-inflammatory agent worthy of further development into a pharmaceutical drug for the treatment of ALI.     

Heme oxygenase-1 ameliorates LPS-induced acute lung injury correlated with downregulation of interleukin-33

Although studies have shown that heme oxygenase-1 (HO-1) can abrogate leukocyte recruitment and tissue injury after LPS stimulation, the underlying mechanisms remain incompletely understood. Interleukin (IL)-33, a new member of the IL-1 family, is found to play a crucial immunoregulatory effect on the MD2/TLR4 complex expression. Moreover, TLR4 further promotes the activation of NF-κB and the production of proinflammatory mediators, which exacerbate neutrophil infiltration and organ damage. The present study was designed to determine whether the protection of HO-1 against LPS-induced acute lung injury (ALI) is involved in downregulation of IL-33. We observed that the levels of IL-33 mRNA and protein in LPS-stimulated macrophages were strongly suppressed by a potent HO-1 inducer, CoPP, treatment. Meanwhile, CoPP significantly reduced the expression of TLR4 and TNF-α in IL-33-pretreated macrophages followed LPS challenge. In the murine model of LPS-induced ALI, CoPP treatment resulted in a remarkable decrease in LPS-mediated leukocyte exudation, Evans blue dye albumin (EBA) leakage as well as histopathologic disruption. Notably, CoPP treatment markedly inhibited the expression of IL-33 and TLR4 in lung tissues under LPS stimulation. Therefore, these data suggest that the cytoprotection of HO-1 in LPS-induced pulmonary injury is associated with negative regulation of IL-33 and TLR4-mediated inflammatory response.     

Heme oxygenase-1 ameliorates LPS-induced acute lung injury correlated with downregulation of interleukin-33

Although studies have shown that heme oxygenase-1 (HO-1) can abrogate leukocyte recruitment and tissue injury after LPS stimulation, the underlying mechanisms remain incompletely understood. Interleukin (IL)-33, a new member of the IL-1 family, is found to play a crucial immunoregulatory effect on the MD2/TLR4 complex expression. Moreover, TLR4 further promotes the activation of NF-κB and the production of proinflammatory mediators, which exacerbate neutrophil infiltration and organ damage. The present study was designed to determine whether the protection of HO-1 against LPS-induced acute lung injury (ALI) is involved in downregulation of IL-33. We observed that the levels of IL-33 mRNA and protein in LPS-stimulated macrophages were strongly suppressed by a potent HO-1 inducer, CoPP, treatment. Meanwhile, CoPP significantly reduced the expression of TLR4 and TNF-α in IL-33-pretreated macrophages followed LPS challenge. In the murine model of LPS-induced ALI, CoPP treatment resulted in a remarkable decrease in LPS-mediated leukocyte exudation, Evans blue dye albumin (EBA) leakage as well as histopathologic disruption. Notably, CoPP treatment markedly inhibited the expression of IL-33 and TLR4 in lung tissues under LPS stimulation. Therefore, these data suggest that the cytoprotection of HO-1 in LPS-induced pulmonary injury is associated with negative regulation of IL-33 and TLR4-mediated inflammatory response.     

Soyasaponin Ab inhibits lipopolysaccharide-induced acute lung injury in mice

Soyasaponin Ab (SA) has been reported to have anti-inflammatory effect. However, the effects of SA on lipopolysaccharide (LPS)-induced acute lung injury (ALI) have not been reported. The aim of this study was to investigate the anti-inflammatory effects of SA on LPS-induced ALI and clarify the possible mechanism. The mice were stimulated with LPS to induce ALI. SA was given 1 h after LPS treatment. 12 h later, lung tissues were collected to assess pathological changes and edema. Bronchoalveolar lavage fluid (BALF) was collected to assess inflammatory cytokines and nitric oxide (NO) production. In vitro, mice alveolar macrophages were used to investigate the anti-inflammatory mechanism of SA. Our results showed that SA attenuated LPS-induced lung pathological changes, edema, the expression of cycloxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in lung tissues, as well as TNF-α, IL-6, IL-1β, and NO production in mice. Meanwhile, SA up-regulated the activities of superoxide dismutase (SOD) and catalase decreased by LPS in mice. SA also inhibited LPS-induced TNF-α, IL-6 and IL-1β production as well as NF-κB activation in alveolar macrophages. Furthermore, SA could activate Liver X Receptor Alpha (LXRα) and knockdown of LXRα by RNAi abrogated the anti-inflammatory effects of SA. In conclusion, the current study demonstrated that SA exhibited protective effects against LPS-induced acute lung injury and the possible mechanism was involved in activating LXRα, thereby inhibiting LPS-induced inflammatory response.     

D(−)-Salicin inhibits the LPS-induced inflammation in RAW264.7 cells and mouse models

D(−)-Salicin is a traditional medicine which has been known to exhibit anti-inflammation and other therapeutic activities. The present study aimed to investigate whether D(−)-Salicin inhibited the LPS-induced inflammation in vivo and in vitro. We evaluated the effect of D(−)-Salicin on cytokines (TNF-α, IL-1β, IL-6 and IL-10) in vivo and in vitro by enzyme-linked immunosorbent assay and signaling pathways (MAPKs and NF-κB) in vivo by Western blot. The results showed that D(−)-Salicin markedly decreased TNF-α, IL-1β and IL-6 concentrations and increased IL-10 concentration. In addition, western blot analysis indicated that D(−)-Salicin suppressed the activation of MAPKs and NF-κB signaling pathways stimulated by LPS. To examine whether D(−)-Salicin ameliorated LPS-induced lung inflammation, inhibitors of MAPKs and NF-κB signaling pathways were administrated intraperitoneally to mice. Interference with specific inhibitors revealed that D(−)-Salicin-mediated cytokine suppression was through MAPKs and NF-κB pathways. In the mouse model of acute lung injury, histopathologic examination indicted that D(−)-Salicin suppressed edema induced by LPS. So it is suggest that D(−)-Salicin might be a potential therapeutic agent against inflammatory diseases.     

Protective effects of pogostone against LPS-induced acute lung injury in mice via regulation of Keap1–Nrf2/NF-κB signaling pathways

Pogostone, a major component of Pogostemon cablin, has been demonstrated to possess antibacterial, anti-fungal, immunosuppressive and anti-inflammatory properties. To investigate the potential therapeutic effect of pogostone on lipopolysaccharide (LPS)-induced acute lung injury (ALI), mice were pretreated with pogostone prior to LPS exposure. After LPS challenge, the lungs were excised and the histological changes, wet to dry weight ratios, MPO activity reflecting neutrophil infiltration, and MDA activity reflecting oxidative stress were examined. The inflammatory cytokines in the BALF were determined by ELISA assay. Moreover, the expressions of p65 and phosphorylated p65 subunit of NF-κB, and Nrf2 in the nucleus in lung tissues were measured by Western blot analysis, and meanwhile the dependent genes of NF-κB and Nrf2 were assessed by RT-qPCR. The results showed that pretreatment with pogostone markedly improved survival rate, attenuated the histological alterations in the lung, reduced the MPO and MDA levels, decreased the wet/dry weight ratio of lungs, down-regulated the level of pro-inflammatory mediators including TNF-a, IL-1β and IL-6. Furthermore, pretreatment with pogostone enhanced the Nrf2 dependent genes including NQO-1, GCLC and HO-1 but suppressed NF-κB regulated genes including TNF-α, IL-1β and IL-6. The mechanism behind the protective effect was correlated with its regulation on the balance between Keap1–Nrf2 and NF-κB signaling pathways. Therefore, pogostone may be considered as a potential therapeutic agent for preventing and treating ALI.     

胆红素对内毒素致大鼠急性肺损伤的保护作用

目的探讨胆红素对内毒素致急性肺损伤(ALI)的保护作用及其可能机制。方法将雄性Wis-tar大鼠30只随机分为正常对照组、ALI模型组和胆红素干预组。检测肺系数(LI)、支气管肺泡灌洗液(BALF)中白细胞(WBC)计数和中性粒细胞(PMN)百分比、蛋白质含量(Pr)、肺泡通透指数(LPI);采用原位杂交技术半定量法和免疫组织化学染色测定肺血管内皮细胞间黏附分子1(ICAM-1)mRNA、核因子κB(NF-κB)和其抑制蛋白I-κBα的表达。结果①ALI模型组LI、BALF中WBC计数、PMN百分比和Pr及LPI均显著高于正常对照组(P均<0.01);胆红素干预组LI、BALF中WBC计数和LPI均显著低于ALI模型组(P均<0.01),PMN百分比和Pr也明显低于ALI模型组(P均<0.05),且与正常对照组差异无统计学意义(P>0.05)。②ALI模型组肺血管内皮ICAM-1 mRNA表达和胞核NF-κB含量与正常对照组比较显著升高(P均<0.01),胞质I-κBα水平却明显降低(P<0.01);胆红素干预组ICAM-1 mRNA表达和胞核NF-κB与模型组相比明显减低(P<0.01),胞质I-κBα含量显著升高(P<0.01),但与正常对照组比较差异有统计学意义(分别P<0.05、P<0.01)。结论胆红素通过抑制NF-κB和ICAM-1 mRNA的表达而减少中性粒细胞肺内浸润来对抗大鼠急性肺损伤。     

S-allylmercaptocysteine ameliorates lipopolysaccharide-induced acute lung injury in mice by inhibiting inflammation and oxidative stress via nuclear factor kappa B and Keap1/Nrf2 pathways

The garlic-derived organosulfur compound S-allylmercaptocysteine (SAMC) has been reported to exhibit anti-inflammatory and anti-oxidative activities, whereas its potential therapeutic effect on lipopolysaccharide (LPS)-induced acute lung injury (ALI) is unknown. In this study, we focused on exploring the therapeutic effects of SAMC on LPS-induced ALI mice and the involvement of underlying molecular mechanisms. BalB/c mice were treated with SAMC (10, 30 and 60 mg/kg) or positive control N-acetylcysteine (NAC, 500 mg/kg) by gavage after intratracheal instillation of LPS for 30 min and were sacrificed 24 h after LPS administration. Our results indicate that the treatment with SAMC not only ameliorated the histological changes but also decreased LPS-triggered lung edema. Moreover, SAMC displayed an anti-inflammatory effect through reducing inflammatory cells infiltration, myeloperoxidase (MPO) formation and inhibiting pro-inflammatory cytokines/mediator production including tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX2) via suppressing the activation of nuclear factor-kappaB (NF-κB) signaling pathway. Furthermore, SAMC attenuated oxidative stress evoked by LPS via diminishing malondialdehyde (MDA) formation and reversing glutathione (GSH) and superoxide dismutase (SOD) depletion. Meanwhile, SAMC up-regulated expressions of endogenous antioxidant/detoxifying proteins including heme oxygenase-1 (HO-1) and NAD(P)H: quinone oxidoreductase 1(NQO1) through reversing the suppression of Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid-2 related factor 2 (Nrf2) signaling pathway. Our results demonstrate that SAMC effectively attenuated LPS-induced ALI which was largely dependent upon inhibition of inflammation and oxidative stress via NF-κB and Keap1/Nrf2 signaling pathways.     

Ginsenoside Rg3 ameliorates lipopolysaccharide-induced acute lung injury in mice through inactivating the nuclear factor-κB (NF-κB) signaling pathway

Ginsenoside Rg3 (GRg3), one of the major active saponins isolated from ginseng (the root of Panax ginseng C.A. Meyer, Araliaceae), has been reported with many health benefits. Currently, the protective effect of GRg3 on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice was investigated. The results indicated that GRg3 treatment could greatly attenuate LPS-induced histopathological alterations in the lung in a concentration-dependent manner. LPS-induced increase of lung wet-to-dry weight ratio (W/D ratio) was also dose-dependently reduced by GRg3 treatment. LPS-induced increases of the total cells, neutrophils and macrophages in the bronchoalveolar lavage fluids (BALFs) were significantly inhibited by GRg3 treatment in a dose-dependent fashion. The levels of pro-inflammatory cytokines including TNF-α, IL-1β and IL-6 in BALFs increased after LPS-induced ALI, which was inhibited by GRg3. Western blot results showed that during ALI LPS activated NF-κB pathway in the lung tissues by upregulating NF-κB p65 phosphorylation and its downstream COX-2 expression; however, these effects of LPS were inhibited by GRg3 treatment. Taken together, these findings in present study suggested that GRg3 provided protective effects against LPS-induced ALI in animal model and might harbor the potential to be considered as drug for the treatment of ALI in clinic.     

Anti-inflammatory effect of Yam Glycoprotein on lipopolysaccharide-induced acute lung injury via the NLRP3 and NF-κB/TLR4 signaling pathway

Acute lung injury (ALI) is a common lung disease accompanied by acute and persistent pulmonary inflammatory response syndrome, which leads to alveolar epithelial cells and capillary endothelial cell damage. Yam glycoprotein, separated from traditional Chinese yam, has been shown to have anti-inflammatory and immunomodulatory effects. In this experiment, we mainly studied the therapeutic effect and mechanism of a glycoprotein on the lipopolysaccharide (LPS)-induced ALI mice. An oral glycoprotein method was used to treat the mouse ALI model induced by LPS injection in the peritoneal cavity. Afterward, we measured the wet/dry (W/D) ratio, the activity of myeloperoxidase (MPO), the oxidative index superoxide dismutase (SOD), malondialdehyde (MDA), glutathione peroxidase (GSH-PX) and the production of inflammatory cytokines interleukin-1β (IL-1β), tumour necrosis factor-α (TNF-α), and interleukin-6 (IL-6) to evaluate the effect of yam glycoprotein on lung tissue changes. We examined the protein expression of TLR4, ASC, NF-κBp65, p-NF-κBp65, Caspase-1, IκB, NLRP3, p-IκB, and β-actin by western blot analysis. Immunohistochemical analyses of NLRP3 and p-p65 in lung tissue were carried out to assess the mechanism of glycoprotein action. This result suggests that glycoprotein markedly depressed LPS-induced lung W/D ratio, MPO activity, MDA content SOD and GSH-Px depletion, and the contents of inflammatory cytokines IL-1β, IL-6, and TNF-α. Moreover, glycoprotein blocked TLR4/NF-κBp65 signaling activation and NLRP3inflammasome expression in LPS-induced ALI mice. As this particular study shows, glycoprotein has a safeguarding effects on LPS-induced ALI mice, possibly via activating NLRP3inflammasome and TLR4/NF-κB signaling pathways.     

Naringin attenuates acute lung injury in LPS-treated mice by inhibiting NF-κB pathway

Naringin has been reported as an effective anti-inflammatory compound. We previously showed that naringin had antitussive effect on experimentally induced cough in guinea pigs. However, the effects and mechanism of naringin on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice are not fully understood. In this study, our aim was to evaluate the anti-inflammatory activities of naringin on LPS-induced ALI in mice and clarify its underlying mechanisms of action. We found that in vivo pretreatment with naringin markedly decreased the lung wet weight to dry weight ratio, and led to significant attenuation of LPS-induced evident lung histopathological changes. Meanwhile, naringin significantly reduced bronchoalveolar lavage fluid (BALF) total cell and neutrophil (PMN) counts after LPS challenge. Furthermore, naringin inhibited myeloperoxidase (MPO: a marker enzyme of neutrophil granule) and inducible nitric oxide synthase (iNOS) activities in lung tissue and alleviated LPS-induced tumor neurosis factor-α (TNF-α) secretion in BALF in a dose-dependent manner. Additionally, Western blotting showed that naringin efficiently blunt NF-κB activation by inhibiting the degradation of I?B-α and the translocation of p65. Taken together, these results suggest that naringin shows anti-inflammatory effects through inhibiting lung edema, MPO and iNOS activities, TNF-α secretion and pulmonary neutrophil infiltration by blockade of NF-κB in LPS-induced ALI.     

氯胺酮对内毒素小鼠肺泡巨噬细胞核因子-κB活化的影响

目的观察不同浓度的氯胺酮对脂多糖(LPS)诱发的小鼠肺泡巨噬细胞核因子(NF)-κB的活化,进一步探讨氯胺酮对急性肺损伤(ALI)/急性呼吸窘迫综合征(ARDS)的应用前景。方法在小鼠肺泡巨噬细胞(PAM)培养液中加入脂多糖(LPS)10μg/ml得到内毒素肺损伤细胞模型。实验分为LPS刺激组(加LPS10μg/ml)、氯胺酮干预组1(同时加入LPS10μg/ml和氯胺酮10μmol/L)、氯胺酮干预组2(同时加入LPS10μg/ml和氯胺酮100μmol/L)、氯胺酮干预组3(同时加入LPS10μg/ml和氯胺酮1000μmol/L)4组。分别于刺激后0.5,1,4,6h留取细胞,用免疫组织化学染色图像分析法检测细胞核中NF-κB活性。结果①LPS+不同浓度的氯胺酮(10,100,1000μmol/L)后,NF-κBp50活性与LPS组相比在1h和4h处有明显的下降(P<0.05),且有剂量依赖性,氯胺酮浓度越大,NF-κBp50活性下降越明显,各组之间差异有统计学意义(P<0.05)。②NF-κBp65活性的检测与NF-κBp50的检测结果相似。结论氯胺酮通过对PAM内NF-κB活化的抑制,可阻止和延缓LPS诱发的ALI的发生,可能有一定的肺保护作用。