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.     

Schisandrin A protects against lipopolysaccharide-induced mastitis through activating Nrf2 signaling pathway and inducing autophagy

Schisandrin A (Sch A), a dibenzocyclooctadiene lignan extracted from Schisandra chinensis (Turcz.) Baill., has anti-oxidant and anti-inflammatory effects, but the effect on masitits has not been studied. Therefore, we investigated the effect of Sch A in cell and mouse models of lipopolysaccharide (LPS)-induced mastitis. Studies in vivo showed that Sch A reduced LPS-induced mammary injury and the production of pro-inflammatory mediators. Sch A also decreased the levels of pro-inflammatory mediators and activated nuclear factor-E2 associated factor 2 (Nrf2) signaling pathway in mouse mammary epithelial cells (mMECs). The Nrf2 inhibitor partially abrogated the downregulation of Sch A on LPS-induced inflammatory response. In addition, LPS stimulation suppressed autophagy, while both Sch A and the autophagy inducer rapamycin activated autophagy in mMECs, which down-regulated inflammatory response. Sch A also restrained LPS-induced phosphorylation of mammalian target of rapamycin (mTOR) and activated AMP-activated protein kinase (AMPK) and unc-51 like kinase 1 (ULK1). In summary, these results suggest that Sch A exerts protective effects in LPS-induced mastitis models by activating Nrf2 signaling pathway and inducing autophagy and the autophagy is initiated by suppressing mTOR signaling pathway and activating AMPK-ULK1 signaling pathway.     

MiR-342 attenuates lipopolysaccharide-induced acute lung injury via inhibiting MAPK1 expression

Micro RNA (miRNA) and mitogen-activated protein kinase (MAPK) are reported as the crucial regulators of inflammatory responses in acute lung injury (ALI). This study will explore the role of the miR-342/MAPK1 axis in regulation of lipopolysaccharide (LPS)-induced ALI. We found that miR-342 was down-regulated in LPS-induced A549 cells compared with the control group with DMSO, accompanied by elevated inflammatory cytokines and apoptosis. Over-expression of miR-342 reduced LPS-induced inflammatory responses and apoptosis in LPS-stimulated A549 cells, and had a protective role in LPS-treated mice with ALI by decreasing levels of inflammatory cytokines, improving survival of mice with ALI, and ameliorating the lung permeability. Dual-luciferase reporter gene assay demonstrated that miR-342 regulated the expression of MAPK1 by directly targeting its 3′ untranslated region (3′-UTR). Mechanistically, MAPK1 silencing abrogated LPS-induced inflammatory injury in A549 cells, and partially enhanced the protective effect of miR-342. Therefore, miR-342 attenuates LPS-induced ALI by targeting MAPK1 expression, thereby protecting against A549 cell injury induced by LPS and lung injury of mice with ALI.     

5'-Monophosphate-activated protein kinase (AMPK) improves autophagic activity in diabetes and diabetic complications

Diabetes mellitus (DM), an endocrine disorder, will be one of the leading causes of death world-wide in about two decades. Cellular injuries and disorders of energy metabolism are two key factors in the pathogenesis of diabetes, which also become the important causes for the process of diabetic complications. AMPK is a key enzyme in maintaining metabolic homeostasis and has been implicated in the activation of autophagy in distinct tissues. An increasing number of researchers have confirmed that autophagy is a potential factor to affect or induce diabetes and its complications nowadays, which could remove cytotoxic proteins and dysfunctional organelles. This review will summarize the regulation of autophagy and AMPK in diabetes and its complications, and explore how AMPK stimulates autophagy in different diabetic syndromes. A deeper understanding of the regulation and activity of AMPK in autophagy would enhance its development as a promising therapeutic target for diabetes treatment.Abbreviations: ACC, carboxylase; AdipoR, adiponectin receptors; ADP, adenosine diphosphate; AMP, adenosine monophosphate; AMPK, 5′-monophosphate-activated protein kinase; ATP, adenosine triphosphate; CaMKK, Ca²⁺ calmodulin-dependent protein kinase kinase; DEPTOR, DEP domain-containing mTOR-interacting protein; DM, Diabetes mellitus; DN, Diabetic nephropathy; ERK, extracellular signal-regulated kinase; FoxO, forkhead box class O; GFRs, glomerular filtration rates; IKK, IκB kinase; JLDG, Jinlida granule; JNK, janus kinase; LC3, light chain 3; LKB1, liver kinase B1; mTOR, mammalian target of rapamycin; mTORC1, mammalian target of rapamycin (mTOR) complex 1; PKC, protein kinase C; PRAS40, proline-rich Akt substrate 40 kDa; RAPTOR, regulator associated protein of mTOR; SOGA, suppressor of glucose form autophagy; SQSTM1, sequestosome 1; STZ, streptozotocin; TSC, tuberous sclerosis complex; ULK1, Unc-51-like kinase 1; VPS34, vacuolar protein-sorting 34KEY WORDS: Diabetes, Autophagy, AMP-activated protein kinases, Diabetic complications     

L6H9 attenuates LPS-induced acute lung injury in rats through targeting MD2

Acute lung injury (ALI) is a clinical syndrome characterized by respiratory failure and acute inflammatory response. Myeloid differentiation protein 2 (MD2) has been reported to play a pivotal role in the recognition of LPS and LPS-mediates inflammatory response. There have been no clinically effective therapeutic drugs for ALI. L6H9, an inhibitor of MD2, showed anti-inflammatory effects and cardiac protective activity. However, its effect on ALI has not been elucidated. In this study, intratracheal instillation of LPS was employed to induce ALI in rats. L6H9 pretreatment attenuates LPS-induced pathological variations in lung tissue and pulmonary edema. LPS instillation enhanced lung microvascular permeability, thereby causing inflammatory cells flow into bronchoalveolar lavage fluid (BALF). However, L6H9 inhibited the LPS-induced upregulation of total protein concentration and the number of inflammatory cells in BALF. In the meantime, macrophages infiltration in lung tissue induced by LPS was also mitigated by L6H9 treatment. Furthermore, L6H9 suppressed LPS-induced inflammatory cytokines expression in BALF, serum, and lung tissue. It is noteworthy that LPS-induced MD2/TLR4 complex formation was inhibited by L6H9 in lung tissue. On the whole, these results show that L6H9 can attenuate LPS-induced ALI in vivo by targeting MD2. Our study provide new candidate for the treatment of ALI.     

Role of M3 mAChR in in vivo and in vitro models of LPS-induced inflammatory response

OBJECTIVE: We tested the potential role of the mAChR in lipopolysaccharide (LPS)-induced inflammatory response in in vivo and in vitro models and a possible signaling pathway involved in the inflammatory process. METHODS: Anesthetized mice were challenged with intratracheal LPS to induce acute lung injury. The cytology and histopathology changes, expression of cytokines and pulmonary vascular permeability were used to evaluate the effects of the cholinergic agent. Alveolar macrophage cell line NR8383 was also used to confirm the role of mAChRs and the molecular mechanisms underlying the LPS-induced events. RESULTS: LPS-induced acute lung injury (ALI) was significantly improved by atropine (a non-selective mAChR antagonist) and 4-DAMP (a M3 mAChR antagonist), as indicated by the diminution of neutrophil infiltration, pulmonary vascular permeability and IL-6 and TNF-α production. LPS-induced TNF-α production from the alveolar macrophage was significantly inhibited by atropine and 4-DAMP, but not pirenzepine (a M1 mAChR antagonist) and methoctramine (a M2 mAChR antagonist). Interestingly, LPS-induced TNF-α production was enhanced by the muscarinic receptor agonist pilocarpine, and treatment with pilocarpine alone was able to trigger TNF-α production from the alveolar macrophage, which was effectively attenuated by 4-DAMP. Western blot analysis showed that LPS-induced degradation of IκBα was strongly blocked by atropine/4-DAMP both in vivo and in vitro, indicating that M3 mAChR was involved in LPS-induced lung inflammation by mediating the NF-κB signaling pathway. CONCLUSION: Our findings bring the evidence that the blockage of mAChR exerts anti-inflammatory properties, in which the M3 mAChR plays an important role in the LPS-induced lung inflammation.     

Obeticholic acid alleviate lipopolysaccharide-induced acute lung injury via its anti-inflammatory effects in mice

Acute lung injury (ALI) is a common disease that may result in acute respiratory failure and death. However, there are still no effective treatments for ALI. Several studies have shown that farnesoid X receptor (FXR) has an anti-inflammatory effect. We investigated the effects of obeticholic acid (OCA), an agonist of FXR, on Lipopolysaccharide (LPS)-induced ALI in mice. Sixty male mice were randomly divided into six groups, and orally administered with or without OCA once daily for 3 consecutive days before LPS (1.0 mg/kg). Animals were sacrificed at 0 h, 2 h or 6 h after LPS. As expected, OCA enhanced pulmonary FXR activity. OCA prevented LPS-induced ALI. Additional experiment showed that OCA alleviated LPS-induced up-regulation of pulmonary pro-inflammatory and chemokine genes. Moreover, OCA also repressed LPS-induced the release of TNF-α and KC in serum and bronchoalveolar lavage fluid. In contrast, OCA further up-regulated LPS-induced the expression of Il-10, an anti-inflammatory cytokine. Further study showed that OCA inhibited LPS-evoked NF-κB signaling in the lungs. OCA attenuated LPS-induced ERK1/2, JNK, p38 and Akt phosphorylation in the lungs. Overall, these results suggest that OCA prevent LPS-induced ALI may be through enhancing pulmonary FXR activity and then blockading several inflammatory signaling pathways.     

sRAGE对脂多糖介导的小鼠急性肺损伤的保护作用

目的探讨可溶性晚期糖基化终末产物受体(sRAGE)对脂多糖(LPS)介导的小鼠急性肺损伤(ALI)的保护作用。方法向小鼠气管内滴注LPS建立ALI模型,造模后1h sRAGE组腹腔注射100μg sRAGE,于24 h留取标本,检测各组动物支气管肺泡灌洗液(BALF)中白细胞及中性粒细胞数量、蛋白浓度和肿瘤坏死因子(TNF)α-水平,并对肺组织进行病理学观察。结果LPS滴注24 h后,BALF中白细胞总数和中性粒细胞数量显著增加,蛋白含量升高,TNFα-释放增多,肺组织出现典型的ALI病理损害,sRAGE干预显著降低了BALF中白细胞及中性粒细胞数量、蛋白含量和TNFα-水平,减轻了LPS引起的肺组织病理改变。结论应用sRAGE阻止RAGE信号通过抑制LPS引起的肺内中性粒细胞聚集、肺毛细血管渗出、炎症因子TNFα-释放,对ALI发挥保护作用。     

Inhibition of spleen tyrosine kinase signaling protects against acute lung injury through blockade of NADPH oxidase and IL-17A in neutrophils and γδ T cells respectively in mice

Acute lung injury (ALI) is one of the most serious complications in critically ill patients which often leads to morbidity and mortality. ALI characterized by severe inflammation of lungs occurs due to uncontrolled inflammatory immune response. However, the immunological mechanism(s) are far from being understood. The spleen tyrosine kinase (SYK), a key component of immune receptor signaling, plays a critical role in the modulation of inflammatory signaling in different immune cells. However, its role in ALI remains to be explored. Therefore, in this study, we investigated the effect of R406, a SYK inhibitor in lipopolysaccharide (LPS)-induced ALI mouse model. LPS led to increased SYK expression in neutrophils and gamma delta (γδ) T cells. This was associated with increased neutrophilic airway inflammation, vascular permeability, myeloperoxidase activity in the lung with upregulated expression of NADPH oxidase (NOX2)/MCP-1/TNF-α in neutrophils and IL-17A in γδ T cells/lung. Pulmonary inflammation was associated with higher mortality in mice with ALI. Inhibition of SYK signaling using R406 in the lung led to blockade of neutrophilic airway inflammation, vascular permeability, pro-inflammatory cytokine release and oxidative stress in innate immune cells, i.e. γδ T cells and neutrophils and the lung. R406 administered LPS group had better survival rate than LPS group. This suggests that SYK upregulation in γδ T cells and neutrophils plays an important role in inflammatory process during ALI. In conclusion, R406 exhibited a great potential to block the LPS-induced airway inflammation and mortality which could be developed as a potential future therapy in ALI.     

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.     

泮托拉唑对急性肺损伤模型大鼠和人肺微血管内皮细胞损伤的作用及作用机制

目的 探讨泮托拉唑对急性肺损伤(ALI)模型大鼠和人肺微血管内皮细胞(HPMECs)损伤的作用及作用机制.方法 将48只SD大鼠随机分为正常对照组,脂多糖组,阳性对照组,泮托拉唑低、高剂量组和泮托拉唑高剂量+氯喹组,各8只.除正常对照组外,其余各组大鼠均腹腔注射5 mg/kg脂多糖复制ALI模型;阳性对照组大鼠腹腔注射...     

Lactoferrin protects against lipopolysaccharide-induced acute lung injury in mice

Lactoferrin (LF) plays various anti-inflammatory roles in inflammation experimentally induced by lipopolysaccharides (LPS). But the protective effects of LF on LPS-induced acute lung injury (ALI) have not been elucidated. In this study, we aimed to study the effects of LF on ALI caused by LPS in mice. At 1h before or after LPS injection, an intraperitoneal injection of LF (5mg/body) was administered. Lung specimens and the bronchoalveolar lavage fluid (BALF) were isolated for histopathological examinations and biochemical analyses 12h after LPS exposure. We found that both prophylactic and therapeutic administration of LF significantly decreased the W/D ratio of the lung and protein concentration in the BALF. LF significantly reduced the pulmonary myeloperoxidase activity and the number of total cells in the BALF 12h after LPS challenge. LF treatment markedly attenuated lung edema, alveolar hemorrhage and inflammatory cells infiltration. Moreover, LF also decreased the production of TNF-α and increased interleukin-10 in the BALF. These results firstly indicate that LF may protect against LPS-induced ALI in mice.     

Protective effects of apocynin nitrone on acute lung injury induced by lipopolysaccharide in rats

Acute lung injury (ALI) is a major cause of mortality and morbidity worldwide. In a previous study we reported the synthesis of a series of apocynin derivatives. Although the anti-inflammatory activity of them contributes to these cytoprotective effects. However, the mechanisms and effects of improving LPS-induced ALI in vivo remain unknown, so the purpose of our investigation was designed to reveal the effect of apocynin derivatives on LPS-induced acute lung injury in rats. The present study showed that apocynin derivatives reduces overall protein levels and tumor necrosis factor α (TNF-α) level, inhibits the activation of NADPH oxidase, and increases the levels of superoxide dismutase (SOD). Especially, compound 11 significantly reduces pulmonary vascular permeability, white blood cell content and protein expressions of p67^phox and p47^phox. These results suggest that compound 11 can ameliorate ALI induced by LPS through inhibition of NADPH oxidase.     

Effectiveness of liposomal-N-acetylcysteine against LPS-induced lung injuries in rodents

Acute lung injury (ALI) and its most severe form, the acute respiratory distress syndrome (ARDS) are frequent complications in critically ill patients and are responsible for significant morbidity and mortality. So far, experimental evidence supports the role of oxidants and oxidative injury in the pathogenesis of ALI/ARDS. In this study, the antioxidant effects of conventional N-acetylcysteine (NAC) and liposomally entrapped N-acetylcysteine (L-NAC) were evaluated in experimental animals challenged with lipopolysaccharide (LPS). Rats were pretreated with empty liposomes, NAC, or L-NAC (25mg/kg body weight, iv); 4h later were challenged with LPS (E. coli, LPS 0111:B4) and sacrificed 20h later. Challenge of saline (SAL)-pretreated animals with LPS resulted in lung injury as evidenced by increases in wet lung weight (edema), increases in lipid peroxidation (marker of oxidative stress), decreases of lung angiotensin-converting enzyme (ACE) (injury marker for pulmonary endothelial cells) and increases in the pro-inflammatory eicosanoids, thromboxane B(2) and leukotriene B(4). The LPS challenge also increased pulmonary myeloperoxidase activity and chloramine concentrations indicative of neutrophil infiltration and activation of the inflammatory response. Pretreatment of animals with L-NAC resulted in significant increases in the levels of non-protein thiols and NAC levels in lung homogenates (p<0.05) and bronchoalveolar lavage fluids (p<0.001), respectively. L-NAC was significantly (p<0.05) more effective than NAC or empty liposomes in attenuating the LPS-induced lung injuries as indicated by the aforementioned injury markers. Our results suggested that the delivery of NAC as a liposomal formulation improved its prophylactic effectiveness against LPS-induced lung injuries.     

DATS对LPS诱导ALI小鼠抗氧化功能及ICAM-1表达的影响

目的探讨二烯丙基三硫(DATS)对脂多糖(LPS)诱导急性肺损伤(ALI)小鼠抗氧化功能及细胞间黏附分子-1(ICAM-1)的影响。方法腹腔注射LPS复制小鼠ALI模型,实验动物随机分为生理盐水对照组、ALI组、DATS预防组、DATS治疗组。测定肺系数、肺组织湿/干重量比值(W/D),以及肺组织丙二醛(MDA)含量、髓过氧化物酶(MPO)活性、超氧化物歧化酶(SOD)活性、总抗氧化能力(T-AOC)活性及ICAM-1的表达。结果 ALI组肺系数、肺组织W/D明显升高,肺组织MDA含量增加,MPO活性升高、SOD活性及T-AOC活性降低,ICAM-1表达增加;预防性应用DATS可减轻肺水肿,减少MDA生成,降低MPO活性、增加SOD活性及T-AOC活性,并使ICAM-1表达减少。DATS治疗组与ALI组相比,各指标均无明显变化。结论预防性应用DATS对LPS诱导的ALI小鼠可发挥抗氧化作用,减轻肺损伤程度。     

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 effects of pravastatin in murine lipopolysaccharide-induced acute lung injury

1. The present study was designed to determine whether pravastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, could attenuate acute lung injury (ALI) induced by lipopolysaccharide (LPS) in BALB/c mice. 2. Acute lung injury was induced successfully by intratracheal administraiton of LPS (3 microg/g) in BALB/c mice. Pravastatin (3, 10 and 30 mg/kg, i.p.) was administered to mice 24 h prior to and then again concomitant with LPS exposure. 3. Challenge with LPS alone produced a significant increase in lung index and the wet/dry weight ratio compared with control animals. Pulmonary microvascular leakage, as indicated by albumin content in the bronchoalveolar lavage fluid (BALF) and extravasation of Evans blue dye albumin into lung tissue, was apparently increased in LPS-exposed mice. Lipopolysaccharide exposure also produced a significant lung inflammatory response, reflected by myeloperoxidase activity and inflammatory cell counts in BALF. Furthermore, histological examination showed that mice exposed to LPS also exhibited prominent inflammatory cell infiltration and occasional alveolar haemorrhage. 4. Pravastatin (3, 10 or 30 mg/kg, i.p.) produced a significant reduction in multiple indices of LPS-induced pulmonary vascular leak and inflammatory cell infiltration into lung tissue. Elevated tumour necrosis factor (TNF)-alpha levels in lung tissue homogenates of ALI mice were significantly decreased after administration of 10 or 30 mg/kg pravastatin. 5. These findings confirm significant protection by pravastatin against LPS-induced lung vascular leak and inflammation and implicate a potential role for statins in the management of ALI. The inhibitory effect of pravastatin was associated with its effect in decreasing TNF-alpha.     

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。     

Sclareol ameliorate lipopolysaccharide-induced acute lung injury through inhibition of MAPK and induction of HO-1 signaling

Sclareol is a natural fragrance compound that is used widely in the cosmetic and food industries. This study examined the effect of sclareol on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. Mice were treated with sclareol 1 h before an intratracheal (I.T.) LPS challenge to induce an ALI model. The effects on lung tissue and lung injury were evaluated 6 h after LPS induction. Pretreatment with sclareol noticeably improved the LPS-induced histological alterations and edema in lung tissue. Sclareol also inhibited the release of pro-inflammatory mediators. Differences in nitric oxide (NO), tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β), IL-6, and IL-10 were found in the bronchoalveolar lavage fluid (BALF) 6 h after LPS-induced lung injury. This study also found a reduced number of total cells and reduced protein concentrations in the BALF. There were also changes in the pulmonary wet/dry (W/D) weight ratio, antioxidant enzyme activity, and myeloperoxidase activity in lung tissues. Sclareol effectively blocked the phosphorylation of mitogen-activated protein kinases (MAPKs) and impeded the protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). The compound boosted the expression of heme oxygenase-1 (HO-1) and inhibited the breakdown of nuclear factor-kappa B (NF-κB) and inhibitor of kappa B (IκBα). To the best of the authors' knowledge, this study is the first to demonstrate that sclareol effectively inhibits acute lung edema, and the results suggest that sclareol may be a potential agent for the treatment of ALI. The potential therapeutic benefits may include the attenuation of LPS-induced pulmonary inflammation due to sclareol's effects on several pathways, including NF-κB, MAPKs and HO-1, as well as the regulation of antioxidant enzyme activity.