Asiatic Acid Inhibits Lipopolysaccharide-Induced Acute Lung Injury in Mice

Asiatic acid (AA), a major triterpene isolated from Centella asiatica (L.) Urban, is known to exert various pharmacological activities, including anti-inflammatory and antioxidant effects. The aim of this study was to evaluate the anti-inflammatory effects of AA on lipopolysaccharide (LPS)-induced acute lung injury (ALI) and clarify the underlying mechanisms. Lung pathological changes were assessed by H&E staining. The myeloperoxidase (MPO) activity was detected by MPO assay. The levels of inflammatory cytokines were measured by ELISA. TLR4 and NF-kB expression was detected by Western blot analysis. AA obviously inhibited LPS-induced lung histopathological changes, MPO activity, and inflammatory cell numbers in bronchoalveolar lavage fluid (BALF). Treatment of AA also inhibited LPS-induced TNF-α, IL-6, and IL-1β production. Furthermore, Western blot analysis showed that AA inhibited LPS-induced TLR4 expression and NF-kB activation. In conclusion, AA inhibited LPS-induced ALI in mice by inhibiting inflammatory cytokine production, which is mediated via blocking of the TLR4/NF-kB signaling pathway.     

Azilsartan attenuates lipopolysaccharide-induced acute lung injury via the Nrf2/HO-1 signaling pathway

Acute lung injury (ALI) is a severe complication of sepsis and hemorrhagic shock with high morbidity. In the present study, the protective effect of Azilsartan on lipopolysaccharide (LPS)-induced ALI in mice was investigated to explore the potential therapeutic property of Azilsartan for the treatment of ALI. LPS was used to induce an ALI model in mice. Hematoxylin–eosin (HE) staining sections were then evaluated for the pathological state of lung tissues. Bronchoalveolar lavage fluid (BALF) protein concentration, wet/dry weight ratios of lung tissues, and pulmonary myeloperoxidase (MPO) activity were detected to determine the degree of pulmonary injury. The number of total cells, macrophages, and neutrophils in BALF were counted using a hemocytometer to illustrate the inflammatory cell infiltration. The lung function was monitored using a spirometer. The concentrations of interleukin-1β (IL-1β), monocyte chemoattractant protein-1 (MCP-1), and interleukin-8 (IL-8) were determined using enzyme-linked immunosorbent assay (ELISA). Oxidative stress was evaluated by the superoxide dismutase (SOD) activity, glutathione (GSH), and malondialdehyde (MDA) concentrations in the lung tissue. The expressions of nuclear erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) were determined using Western blot analysis. Azilsartan therapy alleviated LPS-induced lung tissue damage, increased BALF protein concentration, lung wet to dry weight ratio, MPO activity, and macrophage and neutrophils infiltration. Also, Azilsartan ameliorated the production of inflammatory factors (IL-1β, MCP-1, and IL-8). Azilsartan ameliorated LPS-impaired lung SOD activity, the GSH concentration, and the MDA concentration. Mechanistically, Azilsartan activated the LPS-impaired Nrf2/HO-1 signaling pathway. Azilsartan therapy attenuates LPS-induced ALI via the Nrf2/HO-1 signaling pathway.

     

Protective Effect of Amygdalin on LPS-Induced Acute Lung Injury by Inhibiting NF-κB and NLRP3 Signaling Pathways

The acute lung injury (ALI) is a leading cause of morbidity and mortality in critically ill patients. Amygdalin is derived from the bitter apricot kernel, an efficacious Chinese herbal medicine. Although amygdalin is used by many cancer patients as an antitumor agent, there is no report about the effect of amygdalin on acute lung injury. Here we explored the protective effect of amygdalin on ALI using lipopolysaccharide (LPS)-induced murine model by detecting the lung wet/dry ratio, the myeloperoxidase (MPO) in lung tissues, inflammatory cells in the bronchoalveolar lavage fluid (BALF), inflammatory cytokines production, as well as NLRP3 and NF-κB signaling pathways. The results showed that amygdalin significantly reduced LPS-induced infiltration of inflammatory cells and the production of TNF-α, IL-1β, and IL-6 in the BALF. The activity of MPO and lung wet/dry ratio were also attenuated by amygdalin. Furthermore, the western blotting analysis showed that amygdalin remarkably inhibited LPS-induced NF-κB and NLRP3 activation. These findings indicate that amygdalin has a protective effect on LPS-induced ALI in mice. The mechanism may be related to the inhibition of NF-κB and NLRP3 signaling pathways.     

藤黄酸减轻脂多糖诱导的小鼠急性肺损伤

目的探讨藤黄酸(GA)对脂多糖(LPS)所致小鼠急性肺损伤的保护作用及其机制。方法采用尾静脉注射LPS(4 mg/kg)建立小鼠急性肺损伤模型。实验将小鼠随机分为对照组(control组)、模型组(model组)、藤黄酸组(GA组)和藤黄酸预处理组(GA+LPS组),6 h后测定肺湿/干重比值(W/D);检测髓过氧化物酶(MPO)活性;检测肺泡灌洗液(BALF)中蛋白含量和白细胞计数;ELISA检测肺匀浆中白介素-1β(IL-1β)和肿瘤坏死因子-α(TNF-α)含量。结果模型组小鼠肺W/D、MPO活性、BALF中蛋白含量和白细胞数量均增加,肺组织IL-1β和TNF-α水平升高(均P0.01);藤黄酸预处理可减轻LPS引起的以上指标变化(均P0.05)。结论 GA可减轻LPS诱导的急性肺损伤,其机制可能与降低肺组织IL-1β和TNF-α的含量、抑制中性粒细胞在肺部的聚集和减轻肺部水肿相关。     

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.     

Protective Effect of p-Cymene on Lipopolysaccharide-Induced Acute Lung Injury in Mice

In the previous study, the anti-inflammatory effect of p-cymene had been found. In this study, we investigated anti-inflammatory effects of p-cymene on acute lung injury using lipopolysaccharide (LPS)-induced acute lung injury (ALI) mouse model. The cell counting in the bronchoalveolar lavage fluid (BALF) was measured. The animal lung edema degree was evaluated by wet/dry weight (W/D) ratio. The superoxidase dismutase (SOD) activity and myeloperoxidase (MPO) activity was assayed by SOD and MPO kits, respectively. The levels of inflammatory mediators including tumor necrosis factor alpha (TNF-α), IL-1β, and IL-6 were assayed by enzyme-linked immunosorbent assay method. The pathological changes of the lung tissues were observed by hematoxylin and eosin staining. The inflammatory signal pathway-related protein levels of NF-κB were measured using Western blotting. The data showed that treatment with the p-cymene markedly attenuated inflammatory cell numbers in the BALF, decreased NF-κB protein level in the lungs, improved SOD activity, and inhibited MPO activity. Histological studies demonstrated that p-cymene substantially inhibited LPS-induced neutrophils in the lung tissue compared with the model group. The results indicated that p-cymene had a protective effect on LPS-induced ALI in mice.     

The Effects of Morin on Lipopolysaccharide-Induced Acute Lung Injury by Suppressing the Lung NLRP3 Inflammasome

In previous study, the anti-inflammatory effect of morin had been found. In this study, we investigated anti-inflammatory effects of morin on acute lung injury using lipopolysaccharide (LPS)-induced acute lung injury (ALI) mouse model. The cell counting in the bronchoalveolar lavage fluid (BALF) was measured. The animal lung edema degree was evaluated by wet/dry weight (W/D) ratio. The superoxidase dismutase (SOD) activity and myeloperoxidase (MPO) activity were assayed by SOD and MPO kits, respectively. The levels of inflammatory mediators including tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-18, and IL-6 were assayed by enzyme-linked immunosorbent assay method. Pathological changes of lung tissues were observed by hematoxylin and eosin (HE) staining. The protein level of lung NACHT, LRR, and PYD domains-containing protein 3 (NLRP3) inflammasome was measured by Western blotting. The data showed that treatment with the morin markedly attenuated inflammatory cell numbers in the BALF, decreased lung NLRP3 inflammasome protein level, and improved SOD activity and inhibited MPO activity. Histological studies demonstrated that morin substantially inhibited LPS-induced neutrophils in lung tissue compared with model group. The results indicated that the morin had a protective effect on LPS-induced ALI in mice.     

Anti-inflammatory Effects of Triptolide in LPS-Induced Acute Lung Injury in Mice

Triptolide is one of the main active components of Chinese herb Tripterygium wilfordii Hook F, which has been demonstrated to have anti-inflammatory properties. The aim of this study was to investigate the effects of triptolide on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice and to clarify the possible mechanisms. Mice were administered intranasally with LPS to induce lung injury. Triptolide was administered intraperitoneally 1 h before LPS challenge. Triptolide-treated mice exhibited significantly reduced leukocyte, myeloperoxidase (MPO) activity, edema of the lung, as well as TNF-α, IL-1β, and IL-6 production in the bronchoalveolar lavage fluid compared with LPS-treated mice. Additionally, Western blot analysis showed that triptolide inhibited the phosphorylation of inhibitor-kappa B kinase-alpha (IκB-α), p65, nuclear factor kappa B (NF-κB), p38, extracellular receptor kinase (ERK), and Jun N-terminal kinase (JNK) and the expression of Toll-like receptor 4 (TLR4) caused by LPS. In conclusion, our results suggested that the promising anti-inflammatory mechanism of triptolide may be that triptolide activates peroxisome proliferation-activated receptor gamma (PPAR-γ), thereby attenuating an LPS-induced inflammatory response. Triptolide may be a promising potential therapeutic reagent for ALI treatment.     

Hydrogen Gas Inhalation Attenuates Seawater Instillation-Induced Acute Lung Injury <Emphasis Type="Italic">via</Emphasis> the Nrf2 Pathway in Rabbits

Seawater instillation-induced acute lung injury involves oxidative stress and apoptosis. Although hydrogen gas inhalation is reportedly protective in multiple types of lung injury, the effect of hydrogen gas inhalation on seawater instillation-induced acute lung injury remains unknown. This study investigated the effect of hydrogen gas on seawater instillation-induced acute lung injury and explored the mechanisms involved. Rabbits were randomly assigned to control, hydrogen (2 % hydrogen gas inhalation), seawater (3 mL/kg seawater instillation), and seawater + hydrogen (3 mL/kg seawater instillation?+?2 % hydrogen gas inhalation) groups. Arterial partial oxygen pressure and lung wet/dry weight ratio were detected. Protein content in bronchoalveolar lavage fluid (BALF) and serum as well as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 levels were determined. Hematoxylin-eosin staining was used to monitor changes in lung specimens, and malondialdehyde (MDA) content and myeloperoxidase (MPO) activity were assayed. In addition, NF-E2-related factor (Nrf) 2 and heme oxygenase (HO)-1 mRNA and protein expression were measured, and apoptosis was assessed by measuring caspase-3 expression and using terminal deoxy-nucleotidyl transferase dUTP nick end-labeling (TUNEL) staining. Hydrogen gas inhalation markedly improved lung endothelial permeability and decreased both MDA content and MPO activity in lung tissue; these changes were associated with decreases in TNF-α, IL-1β, and IL-6 in BALF. Hydrogen gas also alleviated histopathological changes and cell apoptosis. Moreover, Nrf2 and HO-1 expressions were significantly activated and caspase-3 expression was inhibited. These results demonstrate that hydrogen gas inhalation attenuates seawater instillation-induced acute lung injury in rabbits and that the protective effects observed may be related to the activation of the Nrf2 pathway.     

天抗(TK)对脂多糖诱导小鼠炎症模型的抗炎作用及其机制

目的研究天抗(TK)对脂多糖(LPS)诱导的小鼠炎症模型的抗炎作用及机制研究。方法将42只昆明小鼠随机分为正常对照(NC)组、模型对照(LPS)组、地塞米松(DXM)组、天抗低(TK-L)、中(TK-M)和高(TK-H)剂量组(0.2,0.8和3.2 g/kg)。各组分别灌胃给药7 d后,腹腔注射30 mg/kg的LPS诱导小鼠急性炎性模型,6 h后处死小鼠,检测小鼠脾脏指数,ELISA测定小鼠血清中IL-1β、IL-6和TNF-α的表达水平;生化法检测小鼠血清中SOD和MDA的表达;qRT-PCR检测小鼠脾脏TLR4、MyD88、TRAF6、p65、IL-1β、IL-6和TNF-αmRNA的表达水平;Western blot检测小鼠脾脏TLR4、MyD88、TRAF6、p-p65和p65蛋白表达水平。结果与LPS组相比,TK组小鼠的脾脏指数明显降低,血清和脾脏组织中IL-1β、IL-6、TNF-α和MDA水平显著下降,SOD水平明显升高,小鼠脾脏组织的TLR4、MyD88、TRAF6和p-p65等蛋白及mRNA表达水平均明显降低。结论天抗对LPS诱导的小鼠急性炎症模型具有抗炎作用,其作用机制可能是通过TLR4/MyD88/NF-κB(p-65)信号通路抑制炎症因子的释放。     

Artesunate Protects Against Sepsis-Induced Lung Injury Via Heme Oxygenase-1 Modulation

Artesunate, a derivative of artemisinin, has anti-inflammatory properties and exerts protective roles in sepsis. Heme oxygense-1 (HO-1) inhibits the inflammatory response through reduction of proinflammatory cytokines and leukocyte influx into tissues. The present study investigated the effects of artesunate on HO-1 and septic lung injury. Cecal ligation and puncture (CLP) was employed to induce septic lung injury. Mice pretreated with artesunate (AS) (15 mg/kg) exhibited decreased sepsis-induced mortality and lung injury and alleviated lung pathological changes and neutrophil infiltration. In addition, AS lowered the levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the serum and bronchoalveolar lavage fluid (BALF) and inhibited cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase isoform (iNOS) expression and NF-κB activation in lung tissue. In addition, AS enhanced NF-E2-related factor-2 (Nrf2) activation and HO-1 expression and enzymatic activity in lung tissue. However, the protective effects of AS on sepsis-induced lung injury were eliminated by ZnPP IX, an HO-1 competitive inhibitor. Therefore, AS plays protective roles in septic lung injury related to the upregulation of HO-1. These findings suggest an effective and applicable treatment to sepsis-induced lung injury and provide new insights into the molecular mechanisms and actions of AS.     

Artesunate Inhibits Renal Ischemia Reperfusion-Stimulated Lung Inflammation in Rats by Activating HO-1 Pathway

Artesunate (AS), a semi-synthetic derivative of Artemisia, has been shown to exert a wide range of pharmacological effects, such as anti-inflammatory and antioxidant functions. However, the protective functions of AS on renal ischemia reperfusion injury (RIR)-stimulated lung inflammation remain unclear. In this research, acute lung injury (ALI) was stimulated by renal ischemia reperfusion injury (RIR). AS (15 mg/kg) was intraperitoneal administrated to rat 1 h before RIR stimulation. Serum and pulmonary NO, MDA, IL-6, MIP-2, and PGE₂ levels, arterial blood gas and biochemistry, lung wet/dry weight ratio and MPO activity, total cell number and protein concentration in BALF, tissue histology, and NF-κB expression were determined. The results indicated that serum and pulmonary NO, MDA, IL-6, MIP-2, and PGE₂ levels, lung wet/dry weight ratio and MPO activity, total cell number, and protein concentration in BALF enhanced after RIR stimulation. These alterations were mitigated by AS. AS attenuated lung wet/dry weight ratio and MPO activity, total cell number, and protein concentration in BALF. AS attenuated RIR-stimulated pulmonary NF-κB phosphorylation. In addition, these previously mentioned actions of AS were antagonized by suppressing HO-1 pathway. However, RIR-stimulated arterial blood gas and biochemistry and lung histopathology were also attenuated by AS. In summary, AS inhibited RIR-stimulated lung inflammation by activating HO-1 pathway.     

Inhibiting Mer receptor tyrosine kinase suppresses STAT1, SOCS1/3, and NF-κB activation and enhances inflammatory responses in lipopolysaccharide-induced acute lung injury

Mer signaling participates in a novel inhibitory pathway in TLR activation. The purpose of the present study was to examine the role of Mer signaling in the down-regulation of TLR4 activation-driven immune responses in mice, i.t.-treated with LPS, using the specific Mer-blocking antibody. At 4 h and 24 h after LPS treatment, expression of Mer protein in alveolar macrophages and lung tissue decreased, sMer in BALF increased significantly, and Mer activation increased. Pretreatment with anti-Mer antibody did not influence the protein levels of Mer and sMer levels. Anti-Mer antibody significantly reduced LPS-induced Mer activation, phosphorylation of Akt and FAK, STAT1 activation, and expression of SOCS1 and -3. Anti-Mer antibody enhanced LPS-induced inflammatory responses, including activation of the NF-κB pathway; the production of TNF-α, IL-1β, and MIP-2 and MMP-9 activity; and accumulation of inflammatory cells and the total protein levels in BALF. These results indicate that Mer plays as an intrinsic feedback inhibitor of the TLR4- and inflammatory mediator-driven immune responses during acute lung injury.     

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.     

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.     

Fisetin Alleviates Lipopolysaccharide-Induced Acute Lung Injury via TLR4-Mediated NF-κB Signaling Pathway in Rats

Acute lung injury (ALI), a common component of systemic inflammatory disease, is a life-threatening condition without many effective treatments. Fisetin, a natural flavonoid from fruits and vegetables, was reported to have wide pharmacological properties such as anti-inflammatory, antioxidant, and anticancer activities. The aim of this study was to detect the effects of fisetin on lipopolysaccharide (LPS)-induced acute lung injury and investigate the potential mechanism. Fisetin was injected (1, 2, and 4 mg/kg, i.v.) 30 min before LPS administration (5 mg/kg, i.v.). Our results showed that fisetin effectively reduced the inflammatory cytokine release and total protein in bronchoalveolar lavage fluids (BALF), decreased the lung wet/dry ratios, and obviously improved the pulmonary histology in LPS-induced ALI. Furthermore, fisetin inhibited LPS-induced increases of neutrophils and macrophage infiltration and attenuated MPO activity in lung tissues. Additionally, fisetin could significantly inhibit the Toll-like receptor 4 (TLR4) expression and the activation of NF-κB in lung tissues. Our data indicates that fisetin has a protective effect against LPS-induced ALI via suppression of TLR4-mediated NF-κB signaling pathways, and fisetin may be a promising candidate for LPS-induced ALI treatment.     

NPS 2143, a selective calcium-sensing receptor antagonist inhibits lipopolysaccharide-induced pulmonary inflammation

NPS 2143, a novel and selective antagonist of calcium-sensing receptor (CaSR) has been reported to possess anti-inflammatory activity. In the present study, we examined the protective effect of NPS 2143 on lipopolysaccharide (LPS)-induced acute lung injury (ALI). NPS 2143 pretreatment significantly inhibited the influx of inflammatory cells and the expression of monocyte chemoattractant protein-1 (MCP-1) in the lung of mice with LPS-induced ALI. NPS 2143 decreased the levels of neutrophil elastase (NE) and protein concentration in the bronchoalveolar lavage fluid (BALF). NPS 2143 also reduced the production of inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the BALF and serum. In addition, NPS 2143 attenuated the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), and increased the activation of AMP-activated protein kinase (AMPK) in the lung. NPS 2143 also downregulated the activation of nuclear factor-kappa B (NF-κB) in the lung. In LPS-stimulated H292 airway epithelial cells, NPS 2143 attenuated the releases of IL-6 and MCP-1. Furthermore, NPS 2143 upregulated the activation of AMPK and downregulated the activation of NF-κB. These results suggest that NPS 2143 could be potential agent for the treatment of inflammatory diseases including ALI.     

Protective Effect of Carvacrol on Acute Lung Injury Induced by Lipopolysaccharide in Mice

Carvacrol, the major component of Plectranthus amboinicus, has been known to exhibit anti-inflammatory activities. The aim of this study was to investigate the effects of carvacrol on lipopolysaccharide (LPS)-induced endotoxemia and acute lung injury (ALI) in mice. Mice were injected intraperitoneally (i.p.) with LPS and the mortality of mice for 7 days were observed twice a day. Meanwhile, the protective effect of carvacrol (20, 40 or 80 mg/kg) on LPS-induced endotoxemia were detected. Using an experimental model of LPS-induced ALI, we examined the effect of carvacrol in resolving lung injury. The results showed that carvacrol could improve survival during lethal endotoxemia and attenuate LPS-induced ALI in mice. The anti-inflammatory mechanisms of carvacrol may be due to its ability to inhibit NF-κB and MAPKs signaling pathways, thereby inhibiting inflammatory cytokines TNF-α, IL-6 and IL-1β production.     

中性粒细胞胞外诱捕网在新生大鼠急性肺损伤中的作用

目的:探讨中性粒细胞胞外诱捕网(NETs)在新生大鼠急性肺损伤(ALI)中的作用。方法:取出生7 d的SD大鼠30只,按照随机数字表法分成生理盐水对照组、ALI组及ALI+脱氧核糖核酸酶(Dnase)组,每组10只。ALI组用脂多糖(LPS)以20 mg/kg的剂量腹腔注射,ALI+Dnase组则在注射LPS后即腹腔注射Dnase(5 mg/kg)。给药6 h后,水合氯醛麻醉大鼠,收集支气管肺泡灌洗液(BALF),荧光酶标仪检测BALF中游离DNA(cf-DNA)的含量;右肺组织固定于4%多聚甲醛中,HE染色观察各组大鼠肺组织形态结构;左肺组织制备肺组织匀浆,酶联免疫吸附测定(ELISA)法检测肺组织匀浆中白细胞介素6(IL-6)及肿瘤坏死因子α(TNF-α)的含量;使用免疫荧光法与Western blot检测各组大鼠肺组织中瓜氨酸化组蛋白H3(CitH3)及髓过氧化物酶(MPO)的生成情况。结果:与对照组相比,ALI组与ALI+Dnase组中cf-DNA、CitH3、MPO、IL-6及TNF-α水平均升高(P<0.05),肺组织中炎性细胞浸润严重;与ALI组相比,ALI+Dnase组新生大鼠肺组织中cf-DNA、Cith3、MPO、IL-6及TNF-α水平降低(P<0.05),ALI+Dnase组炎症浸润程度降低。结论:新生大鼠ALI中,NETs水平为反映肺组织损伤的重要指标,NETs可能为治疗新生儿ALI的新靶点。     

Treatment of Low Molecular Weight Heparin Inhibits Systemic Inflammation and Prevents Endotoxin-Induced Acute Lung Injury in Rats

To determine whether low molecular weight heparin (LMWH) is able to reduce pulmonary inflammation and improve the survival in rats with endotoxin-induced acute lung injury (ALI). Rat ALI model was reproduced by injection of lipopolysaccharide (LPS) into tail vein. Rats were divided randomly into three groups: control group, ALI group, LMWH-treated group. Blood was collected and lung tissue was harvested at the designated time points for analysis. The lung specimens were harvested for morphological studies, streptavidin-peroxidase immunohistochemistry examination. Lung tissue edema was evaluated by tissue water content. The levels of lung tissue myeloperoxidase (MPO) were determined. Meanwhile, the nuclear factor-kappa B (NF-κB) activation, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) levels and high mobility group box 1 (HMGB1) and intercellular adhesion molecule-1 (ICAM-1) protein levels in the lung were studied. In survival studies, a separate group of rats were treated with LMWH or sterile saline after LPS administration. Then, the mortality was recorded. Treatment with LMWH after ALI was associated with a reduction in the severity of LPS-induced lung injury. Treatment with LMWH significantly decreased the expression of TNF-α, IL-1β, HMGB1 and ICAM-1 in the lung of ALI rats. Similarly, treatment with LMWH dramatically diminished LPS-induced neutrophil sequestration and markedly reduced the enhanced lung permeability. In the present study, LMWH administration inhibited the nuclear translocation of NF-κB in the lung. Survival was significantly higher among the LMWH-treated group compared with the ALI group. These data suggest that LMWH attenuates inflammation and prevents lethality in endotoxemic rats.