牛珀至宝微丸对内毒素休克肺组织核转录因子-κB表达的调控

目的观察牛珀至宝微丸对内毒素休克肺损伤时核转录因子-κB表达的影响。方法静脉注射内毒素(LPS)1.5mg/kg、腹腔注射D-氨基半乳糖(D-GalN)100mg/kg造成内毒素休克模型,用牛珀至宝微丸作预治疗处理,免疫组化方法检测NF-κB在肺组织内的表达。结果LPS组阳性表达部位在细胞核,牛珀至宝微丸组表达部位主要在细胞质。牛珀至宝微丸降低NF-κB表达,肺损伤减轻。结论证实牛珀至宝微丸能降低内毒素休克时肺组织NF-κB表达,改变其表达部位,提示牛珀至宝微丸对内毒素休克造成的肺损伤的保护作用可能是通过调控肺组织NF-κB而产生的。     

p38MAPK在LPS诱导的小鼠肺组织诱导性一氧化氮合酶（iNOS） 表达中的作用

革兰氏阴性菌的脂多糖(LPS)在导致休克的同时,可以诱导多个器官和组织iNOS及一系列细胞因子的表达和产生,这些介质在休克发生发展过程中起着重要的作用.然而,参与休克过程的细胞和分子机制到目前为止仍属未知.目的观察LPS诱导小鼠肺组织iNOS表达的变化趋势及信号转导通路--p38丝裂原活化蛋白激酶(p38MAPK)在内毒素休克发生发展中的调控作用.方法1)用不同剂量的LPS对小鼠进行不同时间的处理,收集血液后处死小鼠,取肺组织,液氮速冻保存所有样本,采用Griess法检测血浆一氧化氮(NO)水平,分别用Westernblotting和RT-PCR检测肺组织iNOS蛋白和mRNA表达情况.2)复制内毒素休克模型,将戊巴比妥钠(60mg/kg)腹腔麻醉的BALB/c小鼠在立体分离显微镜(SMZ-1B,Nikon)下进行一侧颈动脉插管,与4道生理记录仪连接,记录血压.腹腔注射LPS(5mg/kg),记录血压变化及发生休克的时间.3)用p38MAPK特异性抑制剂SB203580(12.5mg/kg和25mg/kg,口服)对小鼠进行处理1h后,按前述方法复制休克模型,检测血浆NO水平,iNOS蛋白和mRNA的表达.结果1)未经LPS处理时,麻醉小鼠平均动脉压为(127.5±9.0)mmHg;LPS(5mg/kg)处理后小鼠动脉压呈现双峰型进行性下降,6h后平均动脉压降到(42.0±3.0)mmHg,导致重度休克.2)血浆硝酸盐和亚硝酸盐(一氧化氮,NO)的浓度,肺组织中iNOS蛋白及mRNA的表达以及肺组织湿重/干重比值,LPS处理组显著高于对照组.LPS处理4h后iNOS蛋白和mRNA表达,12-48h表达最显著;其中LPS剂量为20mg/kg时,在同一观察时间段与其他剂量组相比,iNOS的表达强度最大.3)经SB203580处理1h后,可以显著降低内毒素休克小鼠血浆NO水平和肺组织湿重/干重比值,并可显著抑制肺组织中iNOS蛋白和mRNA的表达,但是对血压下降并没有显著影响.结论1)LPS可诱导小鼠血浆一氧化氮(NO)水平升高,肺组织中iNOS蛋白和mRNA表达增加,并存在时间和剂量依赖性;2)p38MAPK信号转导通路可能在内毒素休克肺组织iNOS表达中起重要调节作用,提示可以通过抑制信号转导通路来降低iNOS表达及其它细胞因子的产生,可能对内毒素休克时组织损伤的防治有重要意义.     

PI3K/Nrf2通路在内毒素休克兔肾损伤中的作用

 目的: 探讨磷脂酰肌醇3-激酶/核因子E2相关因子2(PI3K/Nrf2)信号通路在内毒素休克兔急性肾损伤中的作用。方法: 健康清洁级雄性新西兰大白兔50只,随机分为5组(每组10只):对照组(C组)、内毒素休克模型组(L组)、渥曼青霉素+内毒素休克组(WL组)、渥曼青霉素组(W组)和二甲基亚砜组(D组)。W组、WL组经耳缘静脉注射渥曼青霉素0.6 mg/kg,D组注射二甲基亚砜0.08 mL/kg,C组和L组注射等容量生理盐水。30 min后,L组和WL组静脉注射脂多糖5 mg/kg(溶于2 mL生理盐水),C组、W组和D组注射等容量生理盐水。注射脂多糖或生理盐水后6 h处死兔,取肾组织进行肾损伤评分(HSK),测定血尿素氮(BUN)、肌酐(Cr)和尿α1-微球蛋白(α1-MG)浓度,检测肾组织MDA含量及SOD活性,检测肾组织Nrf2和HO-1的mRNA总Akt蛋白、p-Akt蛋白、总Nrf2蛋白、p-Nrf2蛋白、核Nrf2蛋白和HO-1蛋白水平。结果: 与C组、W组及D组比较,L组和WL组HSK、BUN、Cr、α1-MG及MDA含量升高,SOD活性降低,肾组织Nrf2和HO-1的mRNA、p-Akt蛋白、Nrf2总蛋白、p-Nrf2蛋白、Nrf2核蛋白及HO-1蛋白的水平上调(P<0.05)。C组、W组和D组之间上述指标差异无统计学显著性。与L组比较,WL组HSK、BUN、Cr、α1-MG及MDA含量升高,SOD活性降低,肾组织Nrf2和HO-1的mRNA、p-Akt蛋白、Nrf2总蛋白、p-Nrf2蛋白、Nrf2核蛋白及HO-1蛋白的水平降低(P<0.05)。结论: PI3K/Nrf2通路激活是内毒素休克诱发兔急性肾损伤时机体的适应性调节反应机制之一。     

BTK抑制剂GDC-0853通过TLR4/NF-κB通路抑制M1巨噬细胞极化并改善UUO肾损伤

目的探究BTK抑制剂GDC-0853对巨噬细胞极化的影响、对小鼠单侧输尿管梗阻(unilated ureteral obstruction,UUO)肾损伤的缓解作用并揭示其相关的机制。方法使用不同浓度BTK抑制剂GDC-0853(20、50、100μmol/L)干预LPS+IFNγ诱导RAW264.7小鼠M0型巨噬细胞向M1型极化,流式细胞术检测巨噬细胞M1型标记物CD86与M2型标记物CD206的表达频率,实时荧光定量PCR(qRT-PCR)检测肿瘤坏死因子-α(TNF-α)、白细胞介素-6(IL-6)、白细胞介素-23(IL-23)、诱导型一氧化氮合酶(iNOS)mRNA水平,Western blot法检测CD86、iNOS蛋白表达以及TLR4/NF-κB通路相关蛋白的表达情况;60只C57BL/6小鼠随机分为假手术组(sham)、UUO组、UUO+BTK抑制剂GDC-0853(低、中、高剂量)组,分别予以生理盐水和20 mg/kg、50 mg/kg、100 mg/kg GDC-0853灌胃预处理3 d,UUO术后再处理7 d后取小鼠肾组织,HE染色观察肾组织病理变化,免疫组化染色检测iNOS阳性表达。结果与LPS+IFNγ组比较,不同浓度BTK抑制剂GDC-0853干预后,M1型巨噬细胞标记物CD86百分比下降而M2型巨噬细胞标记物CD206百分比上升,TNF-α、IL-6、IL-23、iNOS mRNA表达水平以及CD86、iNOS、TLR4、p-IκBα、p-P65蛋白表达水平也显著下降,且呈剂量依赖性,差异均有统计学意义(P<0.01)。BTK抑制剂GDC-0853处理的小鼠肾组织病理损伤较UUO组呈剂量依赖性地减轻,同时,iNOS阳性表达较UUO组也呈剂量依赖性地减弱,差异有统计学意义(P<0.01)。结论BTK抑制剂GDC-0853可改善小鼠UUO的肾损伤,可能是通过介导TLR4/NF-κB信号通路调控巨噬细胞M1的极化来实现的。     

转录因子NF-κB在内毒素休克中的作用

目的探讨内毒素休克大鼠组织炎性介质的表达特征及其和核转录因子NFκB(nuclearfactorkappaB)的关系。方法应用免疫组织化学技术检测脂多糖(lippolysaccharice,LPS)内毒素休克大鼠肝肾组织转录因子NFκB、炎性介质ICAM1、VCAM1、iNOS的表达。结果LPS内毒素休克大鼠肝肾组织转录因子NFκBp65,炎性介质ICAM1、VCAM1、iNOS阳性细胞率高于正常对照组;炎性介质ICAM-1、VCAM-1、iNOS阳性细胞率与NF-κBp65阳性细胞率成正相关。用吡咯烷二硫氨基甲酸(pyrrolidinedithiocarbmate,PDTC)抑制转录因子NFκB的内毒素休克大鼠炎性介质ICAM1、VCAM1、iNOS阳性细胞率低于LPS组。结论核转录因子NFκB在LPS引起的大鼠内毒素休克炎性介质的表达中起调节作用。     

叉头框蛋白O1在内毒素血症急性肾损伤中的作用

目的:探讨叉头框蛋白O1(forkhead box protein O1,FOXO1)在内毒素血症急性肾损伤(acute kidney injury,AKI)中的作用及相关机制。方法:6～8周龄雄性C57BL/6小鼠腹腔内注射脂多糖(lipopolysaccharide,LPS; 10 mg/kg)诱导内毒素血症AKI模型,检测血清肌酐和血尿素氮。利用Western blot、RT-qPCR和免疫荧光等方法检测小鼠肾组织内FOXO1的表达变化。体外培养人近端肾小管上皮细胞HK-2,LPS诱导内毒素血症AKI肾小管上皮细胞模型,利用FOXO1过表达腺病毒感染HK-2细胞,MTT法检测细胞活力;MitoTracker标记线粒体形态学变化;Mito-SOX检测线粒体超氧化物含量改变;检测FOXO1、促凋亡因子Bax及线粒体氧化磷酸化相关分子mRNA变化,以观察线粒体氧化损伤变化情况。结果:内毒素血症AKI小鼠肾组织FOXO1 mRNA及蛋白表达下调。体外LPS刺激可引起HK-2细胞活力下降,线粒体片段化改变,线粒体超氧化物含量升高,FOXO1 mRNA及蛋白表达下调,Bax表达上调,线粒体氧...     

姜黄素对急性肺损伤大鼠肺组织诱导型一氧化氮合酶和内皮型一氧化氮合酶表达的影响

目的:探讨姜黄素对内毒素(LPS)致急性肺损伤(ALI)模型大鼠肺组织中诱导型一氧化氮合酶(iNOS)和内皮型一氧化氮合酶(eNOS)表达的影响。方法:雄性SD大鼠采用随机数字表法分为对照组、急性肺损伤模型组及姜黄素治疗组。采用一次性气管内滴注内毒素4 mg/kg制备急性肺损伤模型大鼠,治疗组于造模前15 min腹腔注射姜黄素200 mg/kg,于造模后3、6、12 h及24 h取肺组织,观察并比较各组肺组织形态学改变,并检测肺湿/干重比、肺含水量和肺组织中NO的含量,real-time PCR及免疫印迹法检测iNOS和eNOS的mRNA和蛋白表达。结果:模型组大鼠肺湿/干重比、肺组织含水量及NO含量均较对照组明显升高,iNOS的mRNA和蛋白表达量较对照组显著上调,而eNOS的mRNA和蛋白表达量较对照组显著下调。与模型组相比,姜黄素治疗组肺湿/干重比、肺含水量、NO含量均明显降低,iNOS的mRNA和蛋白表达量明显下调,eNOS的mRNA和蛋白表达量明显上调。结论:姜黄素可下调内毒素致急性肺损伤模型大鼠肺组织iNOS表达,并匕调eNOS表达。     

右美托咪定减轻失血性休克/复苏大鼠急性肾损伤

目的:研究右美托咪定对失血性休克/复苏(HS/R)大鼠急性肾损伤的影响。方法:健康雄性Wistar大鼠32只,随机分为4组:生理盐水对照组(NS组)、右美托咪定组(D组)、HS/R组和HS/R+D组。容量复苏后6 h处死动物,采集血和肾组织标本。检测各组血清中肌酐和尿素氮的浓度;检测各组大鼠肾组织中丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性、肿瘤坏死因子α(TNF-α)含量和白细胞介素1β(IL-1β)含量;Western blot法检测肾组织血红素加氧酶1(HO-1)和核因子κB(NF-κB)的表达;HE染色观察肾组织病理学改变。结果:与NS组比较,HS/R组MDA含量升高,SOD活性降低(P0.05);与HS/R组比较,HS/R+D组MDA含量降低,SOD活性升高(P0.05)。与NS组比较,HS/R组TNF-α和IL-1β含量升高(P0.05);与HS/R组比较,HS/R+D组TNF-α和IL-1β含量降低(P0.05)。与NS组比较,HS/R组肾组织NF-κB表达升高;与HS组比较,HS/R+D组肾组织NF-κB表达降低(P0.05)。与NS组比较,HS/R组肾组织HO-1表达升高;与HS/R组比较,HS/R+D组HO-1表达进一步升高(P0.05)。肾组织病理学检查可见,右美托咪定治疗可明显减轻肾细胞变性、坏死及炎性细胞浸润程度。结论:右美托咪定可减轻HS/R大鼠急性肾损伤,其作用机制可能与上调HO-1表达及抑制NF-κB表达有关。     

α黑素细胞刺激素保护内毒素休克小鼠的免疫学机制研究

为研究α黑素细胞刺激素 (α MSH)对内毒素休克小鼠发挥保护作用的免疫学机制 ,将BALB/c小鼠经腹腔注射 (ip)LPS5 0 μg/kg和D 半乳糖胺 (D Gal) 90 0mg/kg建立内毒素休克模型后 ,在不同时间给予α MSHip后观察小鼠的存活率 ;用MTT法测定小鼠血清中IL 1、TNF α、IL 6的含量 ;用Griess试剂测定血清中NO的含量。腹腔巨噬细胞 (MΦ)膜表面免疫相关分子以流式细胞仪检测。结果是给予LPS前 1h、同时和后 1hα MSH 2 5mg/kgip可以明显提高内毒素休克小鼠的存活率 ,其中以给予LPS 1h后注射α MSH疗效最佳 ,能显著降低血清中IL 1、TNF α含量 (P <0 0 0 1) ,增加IL 6的产生 (P <0 0 5 ) ,抑制LPS引起的腹腔MΦ高表达CD14、CD40、CD5 4及CD86分子。因此 ,α MSH降低TNF α、IL 1及NO的含量 ,抑制MΦ膜表面CD14、CD5 4、CD40及CD86的表达 ,在其抗内毒素休克效应中起重要作用。     

槐定碱抑制内毒素血症小鼠肺组织LPS模式识别受体的表达

目的:探讨槐定碱对内毒素血症小鼠肺组织LPS识别受体LBP、CD14、TLR4及下游炎症介质TNF-α的影响及意义。方法:BALB/c小鼠尾静脉注射LPS制备内毒素血症小鼠模型,注射LPS后30分钟给予槐定碱高(12 mg/kg)、中(6mg/kg)、低(3 mg/kg)三个剂量干预,并分别在2、6、12、24小时各时间点取血液和肺组织,肉眼及光镜观察肺组织的病理变化;以肺湿/干重(W/D)比检测肺水含量;用RT-PCR检测肺组织中LBP、CD14、TLR4的mRNA表达;Western blot检测肺组织TLR4蛋白的表达;放免法检测血清TNF-α含量。结果:与内毒素血症模型组小鼠肺组织比较,槐定碱三个剂量干预组均不同程度减轻内毒素血症小鼠肺组织病理损伤,降低肺组织W/D值,并且显著下调同时间点模型小鼠肺组织LBP、CD14、TLR4的mRNA表达及TLR4蛋白的表达;槐定碱高、中剂量干预可显著抑制模型小鼠血清TNF-α水平(P<0.01或P<0.05)。结论:槐定碱对内毒素血症小鼠肺组织的保护作用机制可能与下调LPS识别受体LBP、CD14、TLR4表达,抑制下游炎症因子TNF-α的释放有关。     

Organ-specific and differential requirement of TYK2 and IFNAR1 for LPS-induced iNOS expression in vivo

Lipopolysaccharide (LPS) is an integral structural component of the outer membrane of Gram-negative bacteria and the principal active agent in the pathogenesis of endotoxin shock. LPS is a potent inducer of a variety of cytokines and inflammatory agents that lead to a profound alteration of gene expression patterns in cells and organs. The gene coding for the inducible nitric oxide synthase (iNOS) is highly responsive to LPS in vitro and in vivo and accounts for the production of nitric oxide (NO). The Janus kinase (JAK) family member tyrosine kinase 2 (TYK2) is a constituent of the interferon (IFN) type I response pathway and an important effector in the progression of endotoxin shock. Macrophages deficient for IFNalphabeta receptor chain 1 (IFNAR1) or TYK2 were shown to have an impaired LPS-induced iNOS expression. Here we determined the contribution of IFNAR1 and TYK2 to iNOS expression in vivo in a lethal LPS challenge model. TYK2 and IFNAR1 were found to be crucial for the LPS-induced iNOS mRNA and protein expression in spleen and lung that could be attributed to the Mac3-positive population. In liver LPS-induced iNOS mRNA expression was only partially impaired in TYK2-deficient mice and was unimpaired in IFNAR1-deficient mice, indicating organ specificity. TYK2(-/-) and IFNAR1(-/-) mice also differ with respect to IFNgamma production upon LPS challenge in that TYK2(-/-) mice show a defect while IFNAR1(-/-) mice do not. Our data suggest that iNOS is induced through IFNAR1 and TYK2 in Mac3-positive cells which are the main source of iNOS in spleen and lung. The LPS-induced iNOS expression in liver is independent of IFNAR1 and partially dependent on TYK2, which is most likely due to the lack of IFNgamma production in the absence of TYK2.     

Organ-specific and differential requirement of TYK2 and IFNAR1 for LPS-induced iNOS expression in vivo

Lipopolysaccharide (LPS) is an integral structural component of the outer membrane of Gram-negative bacteria and the principal active agent in the pathogenesis of endotoxin shock. LPS is a potent inducer of a variety of cytokines and inflammatory agents that lead to a profound alteration of gene expression patterns in cells and organs. The gene coding for the inducible nitric oxide synthase (iNOS) is highly responsive to LPS in vitro and in vivo and accounts for the production of nitric oxide (NO). The Janus kinase (JAK) family member tyrosine kinase 2 (TYK2) is a constituent of the interferon (IFN) type I response pathway and an important effector in the progression of endotoxin shock. Macrophages deficient for IFNβ receptor chain 1 (IFNAR1) or TYK2 were shown to have an impaired LPS-induced iNOS expression. Here we determined the contribution of IFNAR1 and TYK2 to iNOS expression in vivo in a lethal LPS challenge model. TYK2 and IFNAR1 were found to be crucial for the LPS-induced iNOS mRNA and protein expression in spleen and lung that could be attributed to the Mac3-positive population. In liver LPS-induced iNOS mRNA expression was only partially impaired in TYK2-deficient mice and was unimpaired in IFNAR1-deficient mice, indicating organ specificity. TYK2^−/− and IFNAR1^−/− mice also differ with respect to IFNγ production upon LPS challenge in that TYK2^−/− mice show a defect while IFNAR1^−/− mice do not. Our data suggest that iNOS is induced through IFNAR1 and TYK2 in Mac3-positive cells which are the main source of iNOS in spleen and lung. The LPS-induced iNOS expression in liver is independent of IFNAR1 and partially dependent on TYK2, which is most likely due to the lack of IFNγ production in the absence of TYK2.     

Effect of Cannabis sativa on oxidative stress and organ damage after systemic endotoxin administration in mice

The effect of Cannabis sativa extract on oxidative stress and organ tissue damage during systemic inflammation was studied. For this purpose, Swiss mice were challenged with a single intraperitoneal dose of lipopolysaccharide (LPS; 200 μg/kg) to mimic aspects of mild systemic infection. Cannabis resin extract (5, 10, or 20 mg/kg) (expressed as Δ⁹-tetrahydrocannabinol) was given via subcutaneous route for 2 days prior to and at the time of endotoxin administration. Mice were euthanized 4 h after LPS injection. Malondialdehyde (MDA), reduced glutathione (GSH), and nitric oxide (nitrite/nitrate) in the brain, liver, kidney, lung, and heart as well as brain glucose were measured. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) were measured in liver homogenates. Histopathological examination of different organs was performed, and immunohistochemical techniques were used to evaluate expression levels of inducible nitric oxide synthase (iNOS) and caspase-3 in the brain and liver. The administration of only cannabis (20 mg/kg) decreased MDA, increased GSH, and decreased glucose level in the brain. No significant effects were observed for cannabis alone on MDA, GSH, or nitric oxide in other organs or on liver enzymes. The administration of LPS increased MDA and nitric oxide, while GSH decreased in different organs. Brain glucose increased by endotoxin. AST, ALT, and ALP were markedly increased in the liver tissue. In LPS-treated mice, cannabis (20 mg/kg) decreased MDA. GSH increased in the brain, kidney, and lung, nitric oxide decreased in the brain and lung while brain glucose decreased after the highest dose of cannabis. Cannabis failed to alter the level of liver enzymes. Histological damage in the brain, kidney, heart, lung, and liver due to endotoxin is increased by cannabis. Increased immunoreactivity of caspase-3 in the cytoplasm of the hepatocytes was observed after LPS and cannabis cotreatment compared with the LPS only group. Caspase-3 immunoreactivity markedly increased in degenerating neurons of the cortex following cannabis and LPS cotreatment. iNOS inmmunoreactivity increased after LPS and more intense iNOS expression was detected in hepatocytes after cannabis and LPS cotreatment. iNOS expression increased after cannabis and LPS treatment especially in the cerebral cortex. Thus, the administration of cannabis decreased tissue oxidative stress but increased organ damage after endotoxin injection in mice.     

Cell-specific nitric oxide synthase-isoenzyme expression and regulation in response to endotoxin in intact rat lungs

Nitric oxide (NO) produced by NO synthase (NOS) serves as a ubiquitous mediator molecule involved in many physiologic lung functions, including regulation of vascular and bronchial tone, immunocompetence, and neuronal signaling. On the other hand, excessive and inappropriate NO synthesis in inflammation and sepsis has been implicated in vascular abnormalities and cell injury. At least three different NOS isoforms (neuronal/brain [bNOS], inducible [iNOS], and endothelial [eNOS]) have been described, which are all expressed in normal lung tissue. We investigated the cell-specific expression of bNOS, iNOS, and eNOS in perfused control rat lungs and lungs undergoing stimulation with endotoxin in the presence and absence of plasma constituents. Lung immunohistochemistry and quantitative evaluation of staining intensity showed endotoxin-induced increase in iNOS expression in particular in bronchial epithelial cells, cells of the bronchus-associated lymphoid tissue (BALT), alveolar macrophages, and vascular smooth muscle cells in a time- and dose-dependent fashion. In endothelial cells, which did not express iNOS at baseline, newly induced iNOS was found in response to endotoxin. In contrast, expression of eNOS was markedly suppressed under endotoxin challenge, particularly in bronchial epithelium, BALT, and alveolar macrophages but also in vascular smooth muscle cells and endothelial cells. eNOS expression in bronchial smooth muscle cells was not altered. In contrast to iNOS and eNOS, cellular expression of bNOS in epithelial cells, nerve fibers, BALT, and endothelial cells did not change in response to endotoxin. All changes in NOS regulation were found to be independent of plasma constituents. We conclude that endotoxin exerts a profound impact on the cell-specific NOS regulation in a large number of lung cell types. Prominent features include de novo synthesis or up-regulation of iNOS, in contrast to down-regulation of eNOS, which may well contribute to vascular abnormalities, inflammatory sequelae, and loss of physiologic functions in septic lung failure.     

N-acetyl-beta-D-glucosaminidase as an early marker and indicator of the extent of kidney and liver lesions in endotoxemia and endotoxic shock

The aim of the study was to answer the question whether the serum level and the urine level of N-acetyl-beta-D-glucosaminidase (NAG) could be the indicator of liver and kidney lesions, and the indicator of the stage of the lesions, in cases of endotoxemia and endotoxin shock. The authors performed the experiment using 60 rabbits as experimental animals. The animals were divided into six groups (10 rabbits in each group); control animals received an equal volume (1.0 ml/kg of body weight) of physiological saline solution. Endotoxin (Lipopolysaccharide E. coli 055 B-5) in doses of 20, 40, 60, 80, and 100 micrograms/kg of body weight were administered in a single intravenous injection to each animal of I-V experimental groups. Using endotoxin in that dose of application, the authors provoked different stages of endotoxemia on the rabbits in the first four experimental groups, and the endotoxin shock on the rabbits of the fifth experimental group. After 18 hours, the rabbits were decapitated, and the levels of NAG in serum, urine, kidney and liver tissues determined. The results showed that the serum increase of NAG activity is caused not only by the lesions of kidney parenchyma, but by the lesions of liver parenchyma too, in the cases of endotoxemia and endotoxin-produced shock; the increase is statistically significant. Urine increase of NAG activity is significant even in cases in which the authors administered very low doses of endotoxin (20 micrograms/kg of body weight), so it can be said that urine NAG activity is a very good indicator of early kidney parenchyma lesions. But, the urine increase of NAG activity is (absolutely) in correlation with the dose of administered endotoxin, so it can be said that urine activity of NAG is the indicator of stage of kidney lesions in cases of endotoxemia and endotoxin-provoked shock.     

Down-regulation of renal endothelial nitric oxide synthase expression in experimental glomerular thrombotic microangiopathy

Infection with certain strains of Escherichia coli and endotoxemia results in renal glomerular thrombotic microangiopathy (TMA) characterized by endothelial swelling and prominent glomerular microthrombus formation. Nitric oxide (NO) is an endogenous biologic modulator with diverse physiologic functions including vasodilation and inhibition of platelet adhesion and aggregation. NO is synthesized from conversion of L-arginine to L-citrulline by a family of NO synthases (NOS), which include constitutive and inducible isoforms. Indirect evidence supports the hypothesis that TMA is associated with depressed intrarenal NO production. However, the effect of TMA on renal tissue NOS expression has not been fully elucidated. We studied rats with TMA induced by iv bolus injection of high dose (20 mg/kg) E. coli endotoxin. Subgroups of six animals each were sacrificed before or at 30, 90, 180, 360, and 720 minutes after the administration of endotoxin. Renal histology and tissue expression of endothelial and inducible nitric oxide synthases (eNOS and iNOS) were examined. Additionally, we examined the effect of endotoxin on glomerular NO production, and eNOS and iNOS protein expression in vitro. Glomerular capillary thrombosis developed by 180 minutes after endotoxin administration in approximately half of the animals. The glomeruli without thrombotic lesions apparent by light microscopy disclosed early signs of TMA characterized by endothelial swelling, platelet accumulation/adhesion, and patchy fibrinogen deposition. These morphologic changes were associated with a marked reduction of renal tissue eNOS expression beyond 180 minutes after the endotoxin administration. The fall in eNOS expression was coupled with a significant rise in iNOS protein abundance, which was expressed largely by glomerular circulating neutrophils and endothelial cells, peritubular vascular endothelium, and collecting ducts of cortex and medulla. In vitro incubation of isolated glomeruli with endotoxin also resulted in a marked reduction in eNOS expression and a significant rise in iNOS content. Administration of E. coli endotoxin leads to a sustained fall in renal eNOS expression both in vivo and in vitro. The associated decline in intrarenal endothelial NO production/availability may result in renal vasoconstriction and a hypercoagulative state, which may contribute to the pathogenesis of endotoxin-induced TMA.     

Calpain inhibition attenuates iNOS production and midzonal hepatic necrosis in a repeat dose model of endotoxemia in rats

Systemic exposure to bacterial lipopolysaccharide (LPS, endotoxin) induces hypotension, disseminated intravascular coagulation and neutrophil infiltration in various organs including the lung, kidney and liver. A rat endotoxemic neutrophilic hepatitis model (repeat dose LPS, 10 mg/kg, i.v. 24 hours apart) was developed exhibiting hepatic neutrophil infiltration and mid-zonal hepatic necrosis. The goal of the study was to investigate the role of the intracellular enzyme calpain in the development of neutrophilic hepatitis with midzonal necrosis in this model. A second goal was to compare the observed protective effects of calpain inhibition with a relatively selective inducible nitric oxide synthase (iNOS) inhibitor aminoguanidine (AG) and an inhibitor of coagulation, heparin. When compared to rats administered LPS alone, administration of calpain 1 inhibitor prior to LPS significantly reduced hepatic iNOS expression, hepatic neutrophil infiltration and attenuated midzonal hepatic necrosis. Administration of AG or heparin prior to LPS also decreased liver iNOS expression, hepatic neutrophil infiltration and liver pathology comparable to calpain inhibition. Blood neutrophil activation, as measured by the neutrophil adhesion molecule CD11b integrin, was upregulated in all the LPS treated groups regardless of inhibitor administration. We conclude that amelioration of liver pathology via calpain inhibition is likely dependent on the down-regulation of iNOS expression in the rat model of LPS-mediated hepatitis.     

Licochalcone A isolated from licorice suppresses lipopolysaccharide-stimulated inflammatory reactions in RAW264.7 cells and endotoxin shock in mice

Licochalcone A (LicA), a major phenolic constituent of the licorice species Glycyrrhiza inflata, exhibits various biological properties, including chemopreventive, anti-bacterial, and anti-spasmodic activity. We report that LicA inhibits inflammatory reactions in macrophages and protects mice from endotoxin shock. Our in vitro experiments showed that LicA suppressed not only the generation of nitric oxide (NO) and prostaglandin (PG)E(2), but also the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 induced by lipopolysaccharide (LPS) in RAW264.7 cells. Similarly, LicA inhibited the production of inflammatory cytokines induced by LPS in RAW264.7 cells, including IL-1 beta and IL-6. In an animal model, LicA protected BALB/c mice from LPS-induced endotoxin shock, possibly through inhibiting the production of inflammatory cytokines and NO. Collectively, LicA inhibited the production of inflammatory mediators and may be a potential target for treatment of various inflammatory diseases.