Toll样受体4在失血性休克复苏致小鼠急性肺损伤中的作用

目的 探讨Toll样受体4(TLR4)在失血性休克复苏致小鼠急性肺损伤中的作用.方法 TLR4基因突变型C3H/HeJ小鼠和野生型C3H/HeN小鼠各24只,两种品系小鼠各随机分为2组:假手术组(S组,n=6)、失血性休克复苏组(HSR组,n=18)制备失血性休克复苏模型,并于复苏后6、24、48 h时各取6只小鼠颈动脉放血处死后开胸取肺组织,免疫组织化学法检测p38 MAPK表达水平,酶联免疫吸附法测定白细胞介素(IL)-10和IL-6含量,透射电镜下观察肺组织超微结构.结果 与C3H/HeN小鼠比较,C3H/HeJ小鼠复苏后肺组织p38 MAPK表达下调,IL-6和IL-10含量降低(P<0.05或0.01),病理损伤程度减轻.两种品系小鼠中,与S组比较,HSR组复苏后24 h时肺组织IL-6和IL-10含量增加,复苏后48 h时肺组织IL-6含量增加(P<0.05或0.01);C3H/HeN小鼠中,与S组比较,HSR组复苏后6 h和24 h时肺组织p38 MAPK蛋白表达上调,复苏后48 h时肺组织IL-10含量增加(P<0.01).结论 TLR4参与小鼠失血性休克复苏致急性肺损伤的发生,其机制与激活p38 MAPK信号转导通路有关.     

Toll样受体4在内毒素和“两次打击”致小鼠急性肺损伤中作用的比较

目的 比较Toll样受体4(TLR-4)在内毒素(LPS)和“两次打击”致小鼠急性肺损伤(ALI)中的作用.方法 雄性野生型小鼠C3H/HeN和TLR-4基因突变型小鼠C3H/HeJ各36只,采用随机数字表法,将2种小鼠各随机分为2组(n＝18),假手术/LPS组(S/LPS组)只进行手术操作而不实施放血诱导休克,失血性休克复苏/LPS组(HSR/LPS组)制备失血性休克复苏模型.复苏后24h时2组气管内滴注LPS 30μg/kg.分别于给予LPS后即刻(T1)、3 h(T2)和6 h(T3)时取6只小鼠,采集动脉血样,测定Pa02,然后处死小鼠,取肺组织,计算肺组织湿/干重比,并测定髓过氧化物酶(MPO)活性、IL-10和IL-6的含量.以T1时均数作为基础值,计算T2.3时各指标的变化率.结果 与S/LPS组比较,C3H/HeN小鼠的HSP/LPS组T2.3时Pa02变化率降低,肺组织W/D比、MPO、IL-6和IL-10的变化率升高(P< 0.05或0.01),C3H/HeJ小鼠的HSR/LPS组T2时Pa02变化率降低,肺组织W/D比、MPO、IL-6和IL-10的变化率升高(P<0.05或0.01),T3时上述指标差异无统计学意义(P＞0.05).结论 与LPS致小鼠ALI中的作用比较,TLR-4在“两次打击”致ALI中的作用明显增强.     

P38MAPK信号通路在失血性休克复苏诱发急性肺损伤小鼠HO-1表达上调中的作用

目的 探讨p38分裂原激活蛋白激酶(p38MAPK)信号通路在失血性休克复苏诱发急性肺损伤小鼠血红素加氧酶1(HO-1)表达上调中的作用.方法 SPF级野生型小鼠C3H/HeN32只32只,10～12周龄,体重20～25 g,随机分为4组(n=8),假手术组(S组):只进行手术操作;失血性休克复苏组(HSR组):股动脉放血,至MAP为40 mm Hg,通过放血和回输血液维持MAP 35～45mmHg,60 min后回输全部血液和等失血量的乳酸钠林格氏液复苏;FR167653组(FR组):静脉注射p38MAPK抑制剂FR167653 5 mg/kg;FR+HSR组:于放血前30 min静脉注射FR167653 5 mg/kg.复苏后6 h处死小鼠,取肺组织,观察病理学结果,并进行病理学评分,计算肺湿/干重比,检测肺组织髓过氧化物酶(MPO)、IL-10、IL-6和HO-1水平以及p38MAPK的激活水平.结果 与S组比较,HSR组肺组织病理学评分、肺湿/干重比、MPO、IL-6、IL-10、HO-1和p38MAPK的激活水平升高,HSR+FR组肺组织病理学评分、肺湿/干重比和HO-1表达水平升高(P＜0.01),FR组上述指标差异无统计学意义(P＞0.05);与HSR组比较,HSR+FR组肺组织病理学评分、肺湿/干重比、MPO、IL-6、IL-10、HO-1和p38 MAPK激活水平降低(P＜0.01).结论 p38MAPK信号通路介导了失血性休克复苏诱发急性肺损伤小鼠HO-1的表达上调.     

盐酸戊乙奎醚预先给药对失血性休克大鼠急性肺损伤时TLR4 mRNA表达的影响

目的 探讨盐酸戊乙奎醚预先给药对失血性休克大鼠急性肺损伤时Toll样受体4(TLR4)mRNA表达的影响.方法 健康SD大鼠40只,体重200～250 g,随机分为5组(n=8):假手术组(S组)、失血性休克致急性肺损伤组(ALI组)和低、中、高剂量盐酸戊乙奎醚预先给药组(P1～3组).S组仅行动静脉穿刺,不放血,ALI组股动脉放血至35～45 mm Hg制备急性肺损伤模型,P1～3组分别于放血前30 min股静脉注射盐酸戊乙奎醚0.3、1.0、3.0 mg/kg,随后制备急性肺损伤模型.各组复苏后4 h时处死大鼠取肺,称重后计算肺湿干重比,检测TLR4 mRNA和NF-κB p65蛋白的表达水平,观察病理学结果.结果 与S组比较,ALI组和P1组TLR4 mRNA、NF-κB p65蛋白表达水平及肺湿干重比升高(P＜0.05或0.01),P2.3组差异无统计学意义(P＞0.05);与ALI组比较,P2,3组TLR4 mRNA、NF-κB p65蛋白表达水平及肺湿干重比降低(P＜0.05或0.01);P2组和P3组上述指标比较差异无统计学意义(P＞0.05).P2,3组肺组织病理学损伤程度较ALI组明显减轻.结论 盐酸戊乙奎醚预先给药可通过抑制肺组织TLR4 mRNA表达上调,进而降低NF-κB活性,从而减轻失血性休克诱发大鼠的急性肺损伤.     

环腺苷酸-蛋白激酶A在大鼠内毒素性急性肺损伤时血红素加氧酶-1表达上调中的作用

目的 探讨环腺苷酸-蛋白激酶A(cAMP-PKA)在大鼠内毒素性急性肺损伤时血红素加氧酶-1(HO-1)表达上调中的作用.方法 健康清洁级雄性SD大鼠48只,体重180 ～ 220 g,2.5 ～ 3.0月龄,采用随机数字表法,将大鼠随机分为4组(n=12)∶正常对照组(C组)股静脉注射生理盐水(LPS溶媒)0.5 ml,2h后皮下注射生理盐水(H89溶媒)0.5 ml;内毒素性急性肺损伤组(ALI组)股静脉注射10 mg/kg LPS 0.5 ml,2h后皮下注射生理盐水0.5 ml; H89+内毒素性急性肺损伤组(H+ALI组),股静脉注射10 mg/kg LPS 0.5 ml,2h后皮下注射5 mg/kg H89 0.5 ml; H89组(H组)股静脉注射生理盐水0.5 ml,2h后皮下注射5 mg/kg H89 0.5 ml.静脉注射LPS后6h时处死大鼠,取肺组织,行病理学评分,测定肺组织含水量;采用Western blot法测定HO-1和PKA表达;采用荧光定量PCR法测定HO-1mRNA表达.结果 与C组比较,ALI组和H+ALI组肺组织含水量和病理学评分升高,肺组织PKA、HO-1和HO-1 mRNA表达上调(P＜0.05),H组上述各指标差异无统计学意义(P＞0.05);与ALI组比较,H+ALI组肺组织含水量和病理学评分升高,肺组织PKA、HO-1和HO-1 mRNA表达下调(P＜0.05).结论 大鼠内毒素性急性肺损伤时HO-1表达上调的机制与cAMP-PKA信号通路活化有一定关系.     

维生素C减轻失血性休克引起的大鼠肺树突细胞聚集及肺损伤

目的 探讨失血性休克对大鼠肺组织树突细胞聚集及肺损伤的影响,以及维生素C的保护作用.方法 SD大鼠(6～7周龄)42只,按数字随机法随机分为对照组、失血性休克2h、6h、24 h组及失血性休克+维生素C2h、6h、24 h组等7组,每组各6只.以股动脉放血法建立大鼠失血性休克模型.免疫组化和逆转录聚合酶链反应(RT-PCR)法检测肺组织树突细胞特异性细胞间粘附分子非整合素蛋白-3(DC-SIGN)表达情况.同时检测肺TNF-α、IL-6含量,髓过氧化物酶(MPO)活性,并进行肺损伤评分.结果 对照组肺中DC-SIGN蛋白表达很少,失血性休克组表达显著升高(P＜0.05),失血性休克后2h肺DC-SIGNmRNA含量就开始增高,休克后24 h仍呈升高趋势.失血性休克组大鼠肺TNF-α、IL-6 mRNA水平升高(P＜0.05),MPO活性增加(P＜0.05),病理损伤显著加重(P＜0.05).失血性休克大鼠在复苏前给予维生素C干预后,上述现象均减轻(P＜0.05).结论 失血性休克可能通过促进肺组织树突细胞聚集引起急性肺损伤.维生素C对这一过程有抑制作用.     

HO-1在小鼠内毒素急性肺损伤中的作用：与调控线粒体质量控制的关系

目的评价血红素氧合酶-1(HO-1)在小鼠内毒素急性肺损伤中的作用及其与调控线粒体质量控制的关系。方法清洁级健康雄性成年C57BL/6小鼠, 基于CRISPER/Cas9开发的EGE系统制备HO-1诱导性基因敲除小鼠, 并构建HO-1过表达腺病毒载体诱导HO-1基因过表达小鼠, 6～8周龄, 体重20～25 g, 采用随机数字表法, 将野生型C57BL/6(WT)、HO-1基因敲除型小鼠(HO-1-/-)和HO-1基因过表达型小鼠(HO-1+/+)分别分为2组(n=6):对照组(WT组、HO-1-/-组和HO-1+/+组)和内毒素急性肺损伤组(ALI组、HO-1-/-+ALI组和HO-1+/++ALI组)。经尾静脉注射LPS 15 mg/kg制备小鼠内毒素急性肺损伤模型, 各对照组给予等容量生理盐水。给予LPS或生理盐水后12 h时处死小鼠取肺组织, 光镜下观察肺组织病理学结果并进行肺损伤评分, 测定肺组织还原型谷胱甘肽(GSH)和氧化型谷胱甘肽(GSSG)含量, 计算GSH/GSSG比值, 透射电镜下观察线粒体超微结构, 测定线粒体膜电位(MMP)水平, 采用Western blot...     

富氢液对脂多糖致小鼠急性肺损伤的影响

目的 评价富氢液对脂多糖(LPS)致小鼠急性肺损伤的影响.方法 成年雄性C57BL/6小鼠32只,体重20 ～ 25 g,采用随机数字表法,将其分为4组(n=8):对照组(C组)、富氢液组(H2组)、急性肺损伤组(ALI组)和急性肺损伤+富氢液组(ALI+ H2组).ALI组和ALI+ H2组分别雾化吸入LPS25 μg(溶于PBS中)制备ALI模型,C组和H2组分别雾化吸入无菌PBS 50μl.H2组和ALI+H2组雾化吸入PBS或LPS后1和12 h时腹腔注射0.6 mmol/L富氢液5 ml/kg.LPS或PBS处理后24 h时,机械通气15 min,行动脉血气分析,计算氧合指数.然后收集支气管肺泡灌洗液(BALF),测定蛋白浓度,计数中性粒细胞(PMN).采用ELISA法检测BALF中TNF-α、IL-1β、IL-6和高迁移率族蛋白1(HMGB1)的浓度.然后处死小鼠,取肺组织,行病理学损伤评分,测定湿重/干重(W/D)比、髓过氧化物酶(MPO)和caspase-3的活性,计算细胞凋亡指数(AI).结果 与C组比较,H2组氧合指数、BALF总蛋白、TNF-α、IL-1β、IL-6和HMGB1的浓度和PMN计数、肺组织病理学损伤评分、W/D比、MPO和caspase-3的活性以及AI差异均无统计学意义(P＞0.05),ALI组和ALI+H2组氧合指数降低,BALF蛋白、TNF-α、IL-1β、IL-6和HMGB1的浓度、PMN计数、肺组织病理学损伤评分、W/D比、MPO和caspase-3 的活性以及AI均升高(P＜0.05);与ALI组比较,ALI+ H2组氧合指数升高,BALF总蛋白、TNF-α、IL-1β、IL-6和HMGB1的浓度、PMN计数、肺组织病理学损伤评分、W/D比、MPO和caspase-3的活性以及AI均降低(P＜0.05).结论 富氢液可减轻LPS致小鼠急性肺损伤,可能与其抗炎和抗凋亡作用有关.     

Toll样受体4在高迁移率族蛋白B1影响小鼠调节性T细胞免疫功能中的作用

目的 探讨腹腔注射高迁移率族蛋白B1(HMGB1)后不同基因型小鼠天然调节性T细胞(CD4~+CD25~+Treg)免疫功能的改变及其受体作用机制.方法 分别给C3H/HeN和C3H/HeJ[分别为Toll样受体4(TLR4)野生型(TLR4~(+/+))和天然突变型(TLR4~(-/-)]小鼠腹腔注射不同剂量HMGB1(0、10、20μg/只),饲养48 h后采用免疫磁珠法分离小鼠脾脏CD4~+CD25~+Treg.体外培养12 h后采用流式细胞仪检测CD4~+CD25~+Treg表达细胞毒性T淋巴细胞相关抗原-4(CTLA-4)表达强度,并应用酶联免疫吸附试验(ELISA)检测CD4~+CD25~+Treg生成白细胞介素(IL)-10量.结果 与对照组比较,20 μg HMGB1攻击后C3H/HeN小鼠CD4~+CD25~+Treg表达CTLA-4水平显著下降(78.70±11.42与60.76±7.64,P<0.01),同时细胞牛成IL-10量也明显降低[(96.89±6.25)ng/L与(47.11±4.25)ng/L,P<0.01];但不同剂量HMGB1攻击可引起C3H/HeJ小鼠CD4~+CD25~+Treg表达CTLA-4明显上调和生成IL-10量不同程度地增加(P<0.01).结论 HMGB1攻击可显著影响CD4~+CD25~+Treg介导的免疫状态,TLR4在HMGB1诱导CD4~+CD25~+Treg免疫活性过程中发挥了重要负向调控作用.     

Effect of TLR-4 and HO-1 on acute lung injury induced by hemorrhagic shock in mice

Objective： To examine whether TLR-4 has an ettect on hemorrhage induced changes in lung, and to investigate the change of heme oxygenase-1 （HO-1） on acute lung injury （ALl） induced by hemorrhagic shock in mice.
Methods： Forty-eight male mice, including C3H/HeN mice and C3H/HeJ mice, were randomly divided into sham group （n=12）, hemorrhagic shock group with twelve mice in each phase. Blood pressure （BP） was monitored continuously by attaching carotid artery catheter to a strain gauge pressure transducer/ polygraph. Arterial blood samples were taken for blood gas analysis. A mouse model of non-lethal hemorrhagic shock and resuscitation was used to observe pulmonary myeloperoxidase （MPO） activity and wet/dry weight ratio （W/D）. The expression of HO- 1 was observed by means of RT-PCR and immunohistochemistry. IL-6 and IL-10 in lung tissue homogenate were assayed by enzyme-linked immunosorbent assay （ELISA）. The pulmo- nary pathologic changes were observed under electron microscope and light microscope.
Results： Compared with sham group, the expression of HO- 1 in lung tissue was significantly higher in Hem 24 h and Hem 48 h of C3H/HeN mice （P〈0.01）. The expression of HO-1 mRNA and the levels of IL-6, IL-10 and MPO in lung tissue were markedly increased in Hem 24 h （P〈0.01 or P〈0.05）; Compared with C3H/HeN mice, the expression of HO- 1 rnRNA and the levels of IL-6 and IL-10 in C3H/HeJ mice significantly decreased in Hem 24 h and Hem 48 h （P〈0.01 or P〈O.05）, and the W/D, MPO in C3H/HeJ mice were obvi- ously lower in Hem 24 h （P〈0.05）. The injuries of lung tissues after hemorrhagic shock have been demonstrated by histological examination with electron microscope and light microscope.
Conclusions： TLR-4 and HO-1 might modulate the bal- ance of pro- and anti-inflammatory processes in inflamma- tory reaction of hemorrhagic shock-induced ALl, and the activation of Toll-like receptor might induce the transcrip- tion activity of HO- 1, which may play a k     

Endotoxin tolerance from lipopolysaccharide pretreatment induces nuclear factor-kappaB alterations not present in C3H/HeJ mice

BACKGROUND: Lipopolysaccharide (LPS) activation of macrophage (MO) cytokine secretion requires activation and translocation of nuclear factor-kappaB (NF-kappaB). Endotoxin tolerance induced in LPS-responsive C3H/HeN MOs by LPS pretreatment results in decreased tumor necrosis factor (TNF) secretion and altered NF-kappaB activation. C3H/HeJ MOs have a genetic defect that renders them tolerant to LPS activation. We hypothesized that the alterations of NF-kappaB activation seen with LPS tolerance in HeN MOs would be present in HeJ mice. METHODS: MOs from C3H/HeJ and C3H/HeN mice were cultured with +/- 10 ng/mL LPS pretreatment for 24 hours and then stimulated with 1 to 1,000 ng/mL LPS. Activation of NF-kappaB was assayed by gel shift using a 32P-labeled specific oligonucleotide 30 minutes after LPS activation. TNF secretion 6 hours after LPS stimulation was measured by bioassay. RESULTS: LPS stimulation activated NF-kappaB in both HeN and HeJ MOs. We observed decreased NF-kappaB activation and a characteristic mobility shift in endotoxin-tolerant MOs from HeN mice that were not present in HeJ MOs. In contrast with the results in HeN mice, LPS pretreatment did not induce any alterations in NF-kappaB activation in HeJ MOs. LPS-stimulated TNF secretion was decreased in HeN MOs after LPS pretreatment. There was no change in TNF secretion in HeJ MOs, but, overall, TNF secretion by these cells was much less than that seen in HeN cells. CONCLUSION: MOs from C3H/HeN mice rendered LPS-tolerant by low-dose LPS pretreatment have alterations in activation of NF-kappaB not present in LPS-hyporesponsive C3H/HeJ mice.     

Macrophage antigen presentation and interleukin 1 production after cecal ligation and puncture in C3H/HeN and C3H/HeJ mice

Following cecal ligation and puncture with a 25-gauge needle, endotoxin-sensitive C3H/HeN mice have a 45% mortality compared with no mortality in endotoxin-resistant C2H/HeJ mice. Macrophage production of interleukin 1 and antigen presentation were studied in these two strains of mice following cecal ligation and puncture at 2, 4, 8, 16, and 24 hours and at 2, 4, 6, and 8 days. Splenic macrophages were cultured with a T-helper cell clone (D10.G4.1), and antigen presentation and interleukin 1 production were measured by D10.G4.1 proliferation. Macrophage antigen presentation by C2H/HeJ mice was markedly increased compared with that in C3H/HeN mice at all times after cecal ligation and puncture, most strikingly at 2 days (185m740 cpm for C3H/HeJ mice vs 30,300 for C2H/HeN mice). Macrophage interleukin 1 production was significantly increased in C3H/HeJ mice vs C3H/HeN mice at all times after cecal ligation and puncture (except at 2 days) and was maximal at 8 days (25,000 cpm for C3H/HeJ mice vs 5190 for C3H/HeN mice). These data suggest that the differences in mortality after cecal ligation and puncture between these two strains of mice may relate to a supranormal response of macrophages of C3H/HeJ mice or to an inadequate response of macrophages of C3H/HeN mice.     

TLR4 influences the humoral and cellular immune response during polymicrobial sepsis

As part of the innate immune system, Toll-like receptors (TLRs) react rapidly on a pathogen challenge without prior exposure. Although it is well known that TLR4 is associated with the receptor for lipopolysaccharide (LPS), its role during sepsis has not yet been clearly defined. To study this, polymicrobial sepsis was induced in male C3H/HeN (TLR4 wild type) and C3H/HeJ (TLR4 mutant) mice by caecal ligation and puncture (CLP).A total of 48 h following the surgical procedure, the mice were sacrificed and plasma was collected. Kupffer cells were isolated and ex vivo cytokine production and plasma levels were determined. Lung neutrophil influx was investigated by myeloperoxidase (MPO) content and immunohistochemistry. T-cell subtypes in blood and spleen were determined by flow cytometry.Mice with intact TLR4 (wild type) had increased Kupffer cell IL-6 production and increased plasma levels as compared with C3H/HeJ mice following sepsis. Furthermore, wild type mice showed increased neutrophil influx in lungs and lower percentages of CD8⁺ splenocytes. This was accompanied with less activity, increased weight loss and decreased core temperature.We conclude that TLR4 influences the humoral and cellular response during the course of sepsis and lack of TLR4 reduces markers of the systemic inflammatory response as well as distant organ damage. Therefore, TLR4 could act as a future therapeutic target modulating the immune response during sepsis.     

Neither Fas ligand nor endotoxin is responsible for inducible peritoneal phagocyte apoptosis during sepsis/peritonitis

Regulation of the phagocyte apoptotic response appears to play a significant role in the pathophysiology of sepsis. In this regard, prior studies have shown that the onset of phagocyte apoptosis, as well as those agents that regulate it at the nidus of infection, differ significantly from those seen in circulation. The aim of this study therefore was to determine if the increase in inducible phagocyte apoptosis and caspase activities seen in the peritoneum during sepsis is due to endotoxin or Fas ligand. To study this, male C3H/HeN (endotoxin-sensitive), C3H/HeJ (endotoxin-tolerant), and C3H/HeJ-FasL(gld) (endotoxin-tolerant/FasL-deficient) mice were subjected to cecal ligation and puncture or sham operation. Twenty-four hours later, phagocytes were collected and cultured with lipopolysaccharide (LPS), then harvested for apoptosis (propidium iodide cell cycle or cell death ELISA analysis), cytokine release (ELISA), and caspase activity (fluorogenic assay) determination. The data indicate that there was a marked increase in apoptosis in LPS-stimulated phagocytes which was associated with a significant increase in caspase 3, 8, and 9 activities but a decrease in caspase 1 activity from C3H/HeN and C3H/HeJ-FasL(gld) septic mice and an increase in caspase 3 and 8 activities in phagocytes from C3H/HeJ septic mice. Furthermore, cells from septic mice, including all three strains, lost their ability to produce IL-1beta and IL-6 in response to LPS stimulation. The inability to completely suppress these changes suggests that neither endotoxin (via signaling through TLR-4 pathway) nor Fas ligand regulates the peritoneal phagocyte apoptotic responses seen during the late phase of polymicrobial sepsis/peritonitis.