亚精胺减轻脂多糖诱导的小鼠急性肺损伤

目的　观察亚精胺（spermidine）对脂多糖（LPS）诱导的急性肺损伤（ALI）的影响。 方法　采用5 mg/kg的LPS经气管滴注,建立ALI小鼠模型。用小动物呼吸机检测亚精胺对ALI小鼠呼吸功能的影响;观察亚精胺对ALI小鼠肺组织形态变化的影响;检测ALI小鼠支气管肺泡灌洗液（BALF）中总蛋白、总细胞数及中性粒细胞数目,并检测髓过氧化物酶（MPO）的水平;qPCR检测ALI小鼠肺组织中TREM-1 mRNA的表达;ELISA检测ALI小鼠BALF中sTREM-1的蛋白水平。 结果　亚精胺可改善ALI小鼠的呼吸功能;减轻LPS诱导的肺部病理损伤;减少蛋白渗出和中性粒细胞浸润;降低ALI小鼠肺内炎症放大受体TREM-1的表达。 结论　亚精胺能减少炎症细胞浸润,抑制炎症因子表达,从而减轻LPS诱导的ALI,其机制可能与亚精胺可抑制ALI小鼠肺组织TREM-1表达有关。     

白藜芦醇通过减弱中性粒细胞迁移和浸润改善LPS诱导的急性肺损伤

目的：探究白藜芦醇（RSV）通过减弱中性粒细胞迁移和浸润改善脂多糖（LPS）诱导的急性肺损伤（ALI）。方法 ：将BALB/c小鼠随机分为对照组、RSV组、模型组及模型+RSV组（LPS+RSV）,模型组和LPS+RSV组采用LPS诱导小鼠ALI模型,RSV组和LPS+RSV组以40 mg/kg RSV灌胃,连续灌胃7 d。末次给药后,收集小鼠支气管肺泡灌洗液（BALF）,检测BALF中白细胞、中性粒细胞和蛋白含量,评估肺组织髓过氧化物（MPO）活性,H-E染色观察肺组织病理损伤,检测肺组织和BALF中炎症细胞因子、趋化因子的表达。体外培养中性粒细胞,分别以1μg/mL LPS、1μg/mL RSV处理细胞,流式细胞术检测中性粒细胞凋亡、趋化因子受体（CXCR2、Mac-1）表达,活性氧荧光探针（DCFH-DA）检测细胞内活性氧（ROS）水平,评估中性粒细胞趋化性和迁移能力,免疫印迹检测核因子NF-κB p65磷酸化水平。结果：与模型组比较,LPS+RSV组BALF中细胞总数、中性粒细胞数、蛋白量、TNF-α、IL-6及CXCL2表达降低,肺组织MPO活性、TNF-α、IL-1β、IL...     

白藜芦醇减轻脂多糖诱导的小鼠急性肺损伤

目的观察白藜芦醇在脂多糖(LPS)诱导的急性肺损伤(ALI)小鼠中的作用,以及白藜芦醇对小鼠肺组织NOD样受体蛋白3(NLRP3)表达的影响。方法将小鼠分为对照组,ALI模型组(经气管滴注5 mg/kg的LPS建立小鼠ALI模型),白藜芦醇干预组(经腹腔注射30 mg/kg白藜芦醇,2 h后,经气管滴注5 mg/kg的LPS)。检测小鼠呼吸功能;HE染色及病理评分观察小鼠肺组织形态的变化;检测支气管肺泡灌洗液(BALF)中总蛋白、总细胞数及中性粒细胞数目,并观察中性粒细胞的活化; ELISA检测BALF中IL-1β和IL-18的蛋白水平;real-time PCR检测小鼠肺组织IL-1β、IL-18、nlrp3、asc及pro-caspase-1 mRNA的表达;Western blot检测肺组织IκB的蛋白表达。结果白藜芦醇可改善ALI小鼠的呼吸功能;减轻LPS诱导的肺部病理损伤;降低ALI小鼠BALF中IL-1β和IL-18的蛋白水平(P0.05);减少ALI小鼠肺组织NLRP3、ASC、pro-caspase-1的表达,增加IκB的蛋白表达(P0.05)。结论白藜芦醇可能抑制NLPR3炎性反应小体活化后产物的表达,最终可减轻LPS诱导的小鼠ALI。     

地塞米松对急性肺损伤中TREM-1表达的影响

目的　探讨地塞米松（Dexamethasone,Dex）对脂多糖（Lipopolysaccharide, LPS）诱导的急性肺损伤(acute lung injury, ALI)小鼠肺组织中髓样细胞表达的触发受体1（triggering receptor expressed on myeloid cells-1,TREM-1）表达的影响。 方法　以昆明小鼠为研究对象,腹腔注射LPS(10 mg/kg)建立ALI模型,30 min后给予不同浓度的Dex（5、10、20、40 mg/kg）处理6 h;选用Dex(10 mg/kg)处理不同的时间（6、12、24、36 h）。HE染色法观察肺组织病理损伤程度; RT-PCR检测肺组织TREM-1mRNA的表达;ELISA检测小鼠支气管肺泡灌洗液中可溶性TREM-1（sTREM-1）蛋白水平。 结果　Dex可减轻肺病理损伤;Dex呈时间依赖性地下调ALI小鼠肺组织的TREM-1 mRNA的表达,且在6 h即可降低;Dex呈剂量依赖地下调ALI小鼠肺组织中TREM-1 mRNA的表达,并在10 mg/kg时开始降低。Dex可降低ALI小鼠支气管肺泡灌洗液中sTREM-1的蛋白水平。 结论　Dex可呈剂量及时间依赖性下调ALI小鼠肺组织中的TREM-1mRNA的表达,并减少肺内髓样细胞胞膜TREM-1的脱落,提示Dex可能通过调节TREM-1的表达,从而抑制ALI早期的炎症级联反应,参与保护肺组织。     

VIP对LPS应激的小鼠成纤维细胞TREM-2表达的影响及其机制

目的　观察血管活性肠肽（vasoactive intestinal peptide,VIP）对脂多糖（lipopolysaccharides, LPS）应激的小鼠成纤维细胞髓样细胞表达触发受体-2（TREM-2）表达的影响,并初步探讨其信号转导通路。 方法　利用LPS腹腔注射建立急性肺损伤（ALI）小鼠模型;采用VIP慢病毒气管滴注,qPCR检测肺组织TREM-2的表达。选用qPCR和流式细胞术检测VIP对LPS应激的小鼠成纤维细胞TREM- 2表达的影响;并观察PKC信号通路阻断剂（H-7）、PKA信号通路阻断剂（H- 89）、MAPK信号通路阻断剂（PD98059）和CaM信号通路阻断剂（W-7）对VIP调控TREM- 2表达的影响。 结果　ALI时小鼠肺组织TREM-2 mRNA表达降低,而VIP可上调肺组织TREM- 2 mRNA的表达。LPS下调小鼠成纤维细胞TREM- 2 mRNA的表达,VIP可呈时间依赖性上调TREM- 2 mRNA的表达（0、3 、6 、12和24 h）,且在6 h达到峰值;并呈剂量相关性上调TREM- 2 mRNA的表达（10-10、10-9、10-8和10-7 mol/L）,以10-8 mol/L作用最明显。VIP对LPS应激6 h增加小鼠成纤维细胞TREM-2 mRNA和蛋白表达的效应可被H-7、PD98059以及W- 7所阻断。 结论　LPS下调小鼠成纤维细胞TREM-2的表达,而VIP可上调LPS应激的小鼠成纤维细胞TREM- 2 mRNA的表达,其胞内信号转导途径可能与PKC、MAPK及CaM有关。     

脂多糖诱导小鼠肺损伤模型巨噬细胞活化及共刺激分子CD40上调研究

目的观察肺泡巨噬细胞（AM）活化过程和共刺激分子CD40表达变化，探讨其在脂多糖（LPS）诱导的小鼠急性肺损伤（ALI）模型中所发挥的作用。方法BALB／c小鼠分为正常对照组和LPS处理组。光镜观察24、48h肺组织病理变化；RT-PCR测定活化巨噬细胞（activated macrophage，AMφ）中TLR4表达；电泳迁移率变动分析（EMSA）检测AMφ核提取物中NF-κB的活性；Northern blot检测CD40 mRNA表达，流式细胞术检测CD40蛋白表达；ELISA测定肺泡灌洗液（BALF）中TNF-α、MIP-2及IL-1β的含量。结果小鼠吸入LPS后，肺泡隔断裂、肺间质充血及肺泡腔中性粒细胞浸润，并检测到AMφ表面TLR4的表达、核转录因子NF-κB活性增强、共刺激分子CD40mRNA和蛋白显著表达，并随着时间延长出现增加趋势，BALF中炎症因子释放增加，正常对照组无明显变化（P〈0．05）。结论LPS诱导的ALI中，AM活化和共刺激分子CD40上调，导致瀑链式炎症反应，造成肺急性炎症损伤。     

地塞米松通过抑制GITR/GITRL信号减轻脂多糖诱导的血管内皮细胞凋亡

目的本研究通过观察地塞米松对急性呼吸窘迫综合征(ARDS)小鼠模型肺部炎症反应及GITR/GITRL信号通路的影响,同时初步探讨地塞米松对LPS诱导人血管内皮细胞GITRL表达以及细胞凋亡的作用。方法制作ARDS动物模型后,取小鼠肺组织行常规HE染色,同时行免疫组化染色检测GITR/GITRL信号蛋白,另外行肺泡灌洗并收集灌洗液(bronchoalveolar lavage fluid,BALF)分类计数炎症细胞,ELISA检测BALF中的炎症因子。利用免疫荧光检测人血管内皮细胞GITRL的表达,另外用流式细胞学分析检测凋亡细胞比例。结果地塞米松明显减少模型小鼠BALF中的炎症细胞以及炎症因子,利用免疫组织化学方法检测实验小鼠肺组织中的GITR/GTIRL信号蛋白发现:对照组小鼠肺组织中有少许的炎性细胞表达GITR;ARDS模型模型组小鼠肺组织中可见明显GITR蛋白表达,主要表达于浸润的炎性细胞;地塞米松干预ARDS模型小鼠后肺组织中GITR表达明显减少;对照组小鼠肺组织中GITRL主要表达于血管内皮细胞,其他组织细胞有少量表达;ARDS模型组小鼠肺组织中可见明显GITRL蛋白表达;地塞米松干预ARDS模型小鼠后肺组织中GITRL表达明显减少。利用流式细胞学分析凋亡比例结果显示:IFN-α组血管内皮细胞凋亡细胞比例明显高于正常对照组,地塞米松干预IFN-α诱导的血管内皮细胞凋亡比例较单独IFN-α干预组明显减少。结论地塞米松减轻ARDS肺部炎症可能通过抑制GITR/GITRL信号减轻IFN-α诱导的血管内皮细胞凋亡来实现。     

短期香烟烟雾及脂多糖气道刺激对小鼠气道免疫细胞的影响

目的：探讨香烟烟雾及脂多糖（LPS）短期刺激对小鼠气道免疫细胞的影响。方法：LPS组小鼠气管内（一次性）滴注10 μg LPS，熏烟组小鼠每天熏9支香烟持续熏4 d，观测不同干预措施对小鼠体重的影响；检测支气管肺泡灌洗液(BALF)总细胞数及细胞分类计数，观察细胞形态，并利用PDB（2-丁酸佛波醇酯）诱导BALF中的细胞检测ROS产出率；荧光定量PCR法检测肺组织中GM-CSF和CXCL15 mRNA 表达。结果：与实验前相比，对照组及LPS组小鼠体重未见明显变化（P>0.05），熏烟组小鼠体重减少了189%，其变化差异明显高于对照组和LPS组（P<0.01）。与对照组相比，熏烟组小鼠气道灌洗液细胞总数和各类细胞总数均无明显变化（P>0.05）；LPS组小鼠气道灌洗液细胞总数、巨噬细胞计数和中性粒细胞计数均高于对照组和熏烟组（P<0.01），且LPS组灌洗液巨噬细胞体积较大，形态不规则，中性粒细胞胞核分叶较对照组多。LPS组小鼠气道灌洗液细胞在PDB的诱导下及没有PDB的诱导下均比对照组和熏烟组具有更高ROS产出率（P<0.01）。与对照组相比，LPS组小鼠肺组织中GM-CSF表达显著增高（P<0.01），但CXCL-15和熏烟组小鼠肺组织中GM-CSF及CXCL-15的表达并未发生改变（P>0.05）。结论：短期香烟烟雾刺激明显引起小鼠体重下降，但未能诱发明显气道炎症反应；10 μg LPS气道滴注可通过增加肺组织GM-CSF的表达，增加中性粒细胞的成熟和募集，增加中性粒细胞内氧化应激反应及产生ROS的能力，诱发明显气道炎症反应。     

重楼皂苷Ⅰ对脂多糖诱导的小鼠急性肺损伤的保护作用研究北大核心CSCD

目的:探究重楼皂苷Ⅰ(PPⅠ)对脂多糖(LPS)诱导的小鼠急性肺损伤(ALI)的作用机制。方法:将小鼠随机分为对照(Control)组、LPS组、PPⅠ5 mg/kg组、PPⅠ10 mg/kg组、PPⅠ20 mg/kg组和地塞米松(DEX)组,每组8只。PPⅠ各组小鼠灌胃相应剂量PPⅠ,DEX组灌胃2 mg/kg DEX,对照组灌胃生理盐水预处理7 d,鼻腔滴入LPS(5 mg/kg)建立小鼠ALI模型。24 h后处死小鼠,收集肺组织和支气管肺泡灌洗液(BALF),检测肺湿/干重(W/D)值;HE染色观察肺组织损伤情况并评分;检测BALF中总蛋白含量、白细胞和巨噬细胞数;试剂盒检测一氧化氮(NO)、髓过氧化物酶(MPO)、超氧化物歧化酶(SOD)和丙二醛(MDA)含量;ELISA检测TNF-α、IL-1β、IL-6水平;Western blot检测小鼠肺组织中p38和AMPK的磷酸化及NLRP3、caspase-1、Nrf2和KEAP1的蛋白表达。结果:与对照组相比,LPS组小鼠肺组织发生病理性变化,肺损伤评分、W/D值、BALF中总蛋白含量、炎症细胞、氧化应激水平和炎症细胞因子含量明显升高(P<0.05,P<0.01),p38磷酸化水平、NLRP3、caspase-1和KEAP1蛋白表达显著上调(P<0.01),AMPK磷酸化水平和Nrf2蛋白表达显著下调(P<0.01)。与LPS组比较,PPⅠ(10 mg/kg和20 mg/kg)和DEX减轻了LPS诱导的ALI,肺损伤评分、W/D值、BALF中总蛋白含量、炎症细胞、氧化应激水平和炎症细胞因子含量明显降低(P<0.05,P<0.01),p38磷酸化水平、NLRP3、caspase-1和KEAP1蛋白表达显著下调(P<0.05,P<0.01),AMPK磷酸化水平和Nrf2蛋白表达显著上调(P<0.05,P<0.01)。结论:PPⅠ能够减轻LPS诱导的小鼠ALI,可能与p38-NLRP3/caspase-1和AMPK-Nrf2/KEAP1信号途径有关。     

1-磷酸鞘氨醇受体2抑制脂多糖诱导的急性肺损伤

 目的: 探讨1-磷酸鞘氨醇受体2(S1P2R)对脂多糖(LPS)诱导的急性肺损伤(ALI)中的作用及机制。方法: 野生小鼠和S1pr2^-/-小鼠经气管滴注LPS,建立急性肺损伤动物模型。LPS注射24 h时观察肺组织的病理改变,测定支气管肺泡灌洗液(BALF)中的蛋白浓度、总细胞数、中性粒细胞的比值及TNF-α、IL-6细胞因子的表达。为了观察S1P2R在肺损伤中的作用机制,LPS注射10 min前野生小鼠和S1pr2^-/-小鼠经尾静脉注射一氧化氮合酶抑制剂L-NAME,LPS注射12 h时,再观察肺的病理组织学变化以及BALF中的蛋白浓度,总细胞数及TNF-α、IL-6细胞因子表达的变化。结果: 与野生小鼠比较,S1pr2^-/-小鼠恶化LPS诱导的急性肺损伤,BALF中的蛋白浓度、总细胞数,中性粒细胞比值及炎症细胞因子表达显著增加。而L-NAME的预处理显著抑制在S1pr2^-/-小鼠LPS诱导加重的急性肺损伤。结论: S1P2R通过抑制NO合成,维持血管屏障,从而抑制急性肺损伤。     

白藜芦醇通过激活SGK1上调急性肺损伤小鼠肺泡上皮钠离子通道的表达

目的探讨白藜芦醇(resveratrol)对急性肺损伤(ALI)小鼠肺泡上皮钠离子通道(ENaC)的作用及可能机制。方法将小鼠随机分为对照(control)组、LPS组、RES组和PP242组,每组6只。苏木精-伊红(HE)染色观察肺组织病理;BCA法测肺泡灌洗液(BALF)中蛋白含量,酶联免疫吸附实验(ELISA)检测炎性因子水平;流式细胞计量术检测BALF中性粒细胞比例;Western blot检测肺组织α-ENaC蛋白表达和SGK1磷酸化水平,实时荧光定量PCR(qPCR)检测肺组织α-ENaC mRNA转录水平。结果 1)与对照组相比,LPS组肺组织损伤明显,BALF中性粒细胞比例、蛋白含量和炎性因子水平明显升高(P0.05),肺组织α-ENaC表达和SGK1磷酸化水平显著下调(P0.05);2)与LPS组相比,RES组肺损伤明显减轻,BALF中性粒细胞比例、蛋白含量和炎性因子水平明显降低(P0.05),伴α-ENaC表达和SGK1磷酸化水平显著上调(P0.05);3)与RES组相比,PP242组肺损伤明显加重,BALF中性粒细胞比例、蛋白含量和炎性因子水平明显升高(P0.05),同时伴α-ENaC表达和SGK1磷酸化水平显著下调(P0.05)。结论 SGK1介导的α-ENaC上调机制参与了RES对ALI的保护作用。     

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

Isorhamnetin has been reported to have anti-inflammatory, anti-oxidative, and anti-proliferative effects. The aim of this study was to investigate the protective effect of isorhamnetin on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice by inhibiting the expression of cyclooxygenase-2 (COX-2). The effects of isorhamnetin on LPS-induced lung pathological damage, wet/dry ratios and the total protein level in bronchoalveolar lavage fluid (BALF), inflammatory cytokine release, myeloperoxidase (MPO) and superoxide dismutase (SOD) activities, and malondialdehyde (MDA) level were examined. In addition, the COX-2 activation in lung tissues was detected by Western blot. Isorhamnetin pretreatment improved the mice survival rates. Moreover, isorhamnetin pretreatment significantly attenuated edema and the pathological changes in the lung and inhibited protein extravasation in BALF. Isorhamnetin also significantly decreased the levels of inflammatory cytokines in BALF. In addition, isorhamnetin markedly prevented LPS-induced oxidative stress. Furthermore, isorhamnetin pretreatment significantly suppressed LPS-induced activation of COX-2. Isorhamnetin has been demonstrated to protect mice from LPS-induced ALI by inhibiting the expression of COX-2.     

Vagal Efferent Fiber Stimulation Ameliorates Pulmonary Microvascular Endothelial Cell Injury by Downregulating Inflammatory Responses

Electrical stimulation of the vagus nerve may have positive effects on many inflammatory diseases. This study determined the beneficial effects of vagus nerve stimulation and the mechanisms by which it attenuates lipopolysaccharide (LPS)-induced acute lung injury (ALI). Rats were intraperitoneally injected with 10 mg/kg LPS to induce ALI. The results showed that vagus nerve stimulation could improve lung injury, as evidenced by remarkable reductions in lung edema (wet-to-dry weight ratio), neutrophil infiltration (myeloperoxidase activity), and pulmonary permeability [total number of cells and protein concentrations in bronchoalveolar lavage fluid (BALF)]. In addition, vagus nerve stimulation not only decreased the expressions of Src-suppressed C kinase substrate and E-selectin proteins in lung tissue but also effectively attenuated the concentrations of the proinflammatory cytokines tumor necrosis factor-α, interleukin-1β, and interleukin-6 in BALF. These suggest that vagus nerve stimulation is a suitable treatment for LPS-induced ALI and indicate that it helps ameliorate pulmonary microvascular endothelial cell injury by downregulating inflammatory responses.     

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.

     

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.     

CD40 plays a crucial role in lipopolysaccharide-induced acute lung injury

Activated alveolar macrophages (AMphi) are known to constitute a critical modulator of the lung inflammatory response through the production of various mediators. However, the role of activated AMphi in acute lung injury (ALI) and acute respiratory distress syndrome is less well known. To address this issue, we examined a lipopolysaccharide (LPS)-induced lung injury model for the role of activated AMphi in vivo, focusing on activation through CD40, which is one of the most important pathways for the activation of antigen-presenting cells. Without CD40, LPS-induced ALI was significantly reduced in its histological degree of injury and recruitment of neutrophils into the lung. In addition, the release in the lung of inflammatory mediators such as tumor necrosis factor-alpha, interleukin-1beta, macrophage inflammatory protein 2, or matrix metalloproteinase was significantly reduced in mice deficient in CD40 (CD40KO). To elucidate the mechanism of this attenuation of ALI in CD40KO mice, we studied the function of AMphi ex vivo. AMphi purified from CD40KO mice could not induce expression of inducible nitric oxide synthase (iNOS) by LPS, although iNOS in wild-type AMphi was induced by LPS independently of CD40-CD154 interaction. The loss of surface expression of CD40 was enough to interrupt the expression of iNOS in AMphi in response to LPS. Also based on the tissue nitrotyrosine staining, the reactive oxygen and nitrogen intermediates seemed to be reduced in tissue in CD40KO mice. These results indicated that activation of AMphi through CD40 might be involved not only in amplification by the interaction with CD154 but also in the development of ALI by CD40 itself, and that the functional blockade of CD40 would yield one of the targets for the treatment of LPS-induced ALI and acute respiratory distress syndrome.