允许性高碳酸血症对大鼠机械通气相关性肺损伤NF-κB表达的影响

目的:探讨允许性高碳酸血症对大鼠机械通气相关性肺损伤(VILI)时NF-κB表达的影响。方法:健康雄性Wistar大鼠30只,体重220~280 g,采用随机数字表法,将大鼠随机分3组(n=10):对照组(C组)保留自主呼吸、机械通气肺损伤组(V组)和VILI+高碳酸血症干预治疗组(H组)行机械通气4 h。采用吸气相高气道压机械通气模式制备机械通气相关性肺损伤模型。H组通过调整吸入的CO2浓度来维持动脉血PaCO_2分别为80~100 mm Hg。于机械通气15 min时、机械通气1 h、2 h和4 h时记录MAP,采集股动脉血样,进行动脉血气分析,记录PaO_2;机械通气结束时,测定支气管肺泡灌洗液(BALF)中总蛋白、TNF-α和巨噬细胞炎症蛋白-2(MIP-2)的浓度;取肺组织,测定湿干重比(W/D比)、细胞间粘附分子(ICAM-1)和NF-κb蛋白的表达水平,并观察病理学结果,进行肺损伤评分。测定肺组织丙二醛(MDA)含量及过氧化物歧化酶(SOD)活性。结果:与C组比较,V组和H组肺损伤评分、W/D比、ICAM-1表达水平、BALF中总蛋白浓度、TNF-α和MIP-2浓度、MDA含量和肺组织NF-κB活性升高,PaO_2降低(P0.05);与V组比较,H组肺损伤评分、W/D比、ICAM-1表达水平、BALF中总蛋白浓度、TNF-α和MIP-2浓度和肺组织NF-κB表达降低,SOD活性增强,PaO_2升高(P0.05)。结论:允许性高碳酸血症可下调NF-κB的表达,从而抑制炎症反应减轻大鼠机械通气相关性肺损伤。     

允许性高碳酸血症对大鼠机械通气相关性肺损伤NF-kB 表达的影响

目的：探讨允许性高碳酸血症对大鼠机械通气相关性肺损伤（VILI）时NF-kB 表达的影响。方法：健康雄性Wistar 大鼠30 只,体重220～280 g,采用随机数字表法,将大鼠随机分3 组（n=10)：对照组（C 组）保留自主呼吸、机械通气肺损伤组（V 组）和 VILI+ 高碳酸血症干预治疗组(H 组)行机械通气4 h。采用吸气相高气道压机械通气模式制备机械通气相关性肺损伤模型。H 组通 过调整吸入的CO2浓度来维持动脉血PaCO2分别为80～100 mmHg。于机械通气15 min 时、机械通气1 h、2 h和4 h 时记录 MAP,采集股动脉血样,进行动脉血气分析,记录PaO2;机械通气结束时,测定支气管肺泡灌洗液(BALF)中总蛋白、TNF-琢和巨噬 细胞炎症蛋白-2（MIP-2）的浓度;取肺组织,测定湿干重比（W/D 比）、细胞间粘附分子（ICAM-1）和NF-kb 蛋白的表达水平,并观 察病理学结果,进行肺损伤评分。测定肺组织丙二醛（MDA）含量及过氧化物歧化酶（SOD）活性。结果：与C 组比较,V 组和H 组 肺损伤评分、W/D 比、ICAM-1表达水平、BALF中总蛋白浓度、TNF-alpha和MIP-2 浓度、MDA 含量和肺组织NF-资B 活性升高,PaO2 降低（P<0.05）;与V 组比较,H 组肺损伤评分、W/D 比、ICAM-1表达水平、BALF 中总蛋白浓度、TNF-alpha和MIP-2 浓度和肺组织 NF-kB 表达降低,SOD活性增强,PaO2升高（P<0.05）。结论：允许性高碳酸血症可下调NF-资B的表达,从而抑制炎症反应减轻大 鼠机械通气相关性肺损伤。     

p38丝裂原活化蛋白激酶在大鼠油酸型急性肺损伤中的作用

目的:研究p38丝裂原活化蛋白激酶(p38MAPK)通路抑制剂SB203580对油酸性急性肺损伤(ALI)大鼠炎症反应及肺水清除的影响,探讨油酸性急性肺损伤中p38MAPK的作用机制,为p38MAPK抑制剂SB203580干预脂肪栓塞综合征诱导肺损伤提供新途径。方法:24只SD雄性成年大鼠随机分为对照组(8只)、油酸模型组(8只)和SB203580干预组(8只)。油酸模型组大鼠经右颈静脉注射油酸0.20 ml/kg,造成急性肺损伤模型;SB203580组大鼠在油酸造模前30 min静脉注射SB203580;建模4 h后处死动物,检测血气分析、右下肺湿干重比(W/D)、肺系数(LI)、肺通透指数(PPI),ELISA法检测支气管肺泡灌洗液(BALF)中TNF-α含量,免疫组化和Western blot法检测肺组织p38MAPK、p-p38MAPK蛋白表达水平,检测肺组织病理变化。结果:与对照组相比,油酸模型组大鼠Pa O2及Pa O2/Fi O2明显降低,右下肺湿干重、肺系数和肺通透指数、BALF中炎症因子TNF-α的含量以及pp38MAPK蛋白表达均明显增加(P0.01),肺组织病理学显示明显的急性肺损伤;与油酸模型组相比,以上指标在SB203580干预组则明显改善(P0.01)。结论:p38MAPK信号通路介导的炎性反应在油酸性肺损伤的发病机制中具有重要作用,p38MAPK抑制剂SB203580显著抑制炎症因子的表达,减轻肺水肿,对油酸性肺损伤具有明显的肺保护作用,意味着对p38MAPK的抑制可望为临床上伴有脂肪栓塞综合征(FES)的ALI的防治提供新途径。     

高碳酸血症对急性肺损伤时核因子-κB和TNF-α的影响

目的:观察高碳酸血症对兔急性肺损伤(ALI)模型核因子-κB(NF-κB)和TNF-α表达的影响,探讨其对ALI的作用机制.方法:22只新西兰大白兔随机分为对照组(C组)、非高CO2通气组(N组)、高CO2(8%)通气组(H组).N组和H组通过静脉注射油酸(0.1ml/kg)复制ALI模型,观察肺组织中NF-κB的表达情况、血清和BALF中TNF-α的含量变化及肺组织病理学改变.结果:血清及BALF中TNF-α含量N组和H组高于C组(P＜0.01,P＜0.05),且N组高于H组(P＜0.05).免疫组化及蛋白印迹分析表明H组NF-κB的表达较N组减少(P＜0.05).H组气道峰压显著低于N组,动态胸肺顺应性显著高于N组.动脉血氧分压H组明显高于N组(均P＜0.05).H组病理组织学改变较N组明显减轻.结论:机械通气时吸入8%的CO2所致高碳酸血症对ALI动物模型有保护作用,其机制可能与高碳酸血症抑制NF-κB的活化,从而抑制炎症介质如TNF-α的表达有关.     

原儿茶酸对脂多糖诱导的急性肺损伤小鼠的保护作用

目的:探索原儿茶酸(protocatechuicacid,PCA)对脂多糖(lipopolysaccharide,LPS)诱导的急性肺损伤(acute lung injury,ALI)小鼠的保护作用,探讨其保护机制。方法:将40只昆明小鼠按随机数字表法均分为空白对照组(NC组)、LPS模型组、原儿茶酸预处理组(PCA+LPS组)、地塞米松阳性对照组(Dex+LPS组),每组10只,模型组以5mg·kg-1脂多糖腹腔内注射诱导急性肺损伤。6h后处死小鼠,HE染色观察肺组织病理学变化;BCA法检测肺泡灌洗液中总蛋白浓度;ELISA检测肺泡灌洗液炎症因子TNF-α、IL-1β含量;Western Blot检测肺组织中p38MAPK、p-p38MAPK、p-ATF2蛋白的表达水平。结果:与对照组相比,模型组小鼠肺损伤明显,肺泡内出血、水肿、炎细胞浸润,肺泡灌洗液中TNF-α、IL-1β的含量及总蛋白浓度增加,肺组织中p38MAPK/p-p38MAPK、p-ATF2表达均明显增加(均P0.01)。与模型组相比,原儿茶酸预处理组、地塞米松阳性对照组肺组织病理损伤程度明显减轻,肺泡灌洗液中TNF-α、IL-1β的含量及总蛋白浓度、肺组织中p38MAPK/p-p38MAPK、p-ATF2表达均明显降低(均P0.01)。结论:PCA对LPS诱导的急性肺损伤有保护作用,其作用机制可能与其抑制p38MAPK-p-ATF2信号通路的活化、降低肺组织炎症反应有关。     

黔产毛蒟挥发油对油酸致大鼠急性肺损伤的影响及其机制

为研究黔产毛蒟挥发油在油酸诱导的大鼠急性肺损伤中的作用及其机制。实验将雄性成年清洁级SD大鼠按照体重随机分为对照组、油酸模型组和毛蒟挥发油组(0.125、0.25、0.5 mL/kg)。油酸模型组大鼠采用右侧颈静脉注射油酸0.2 mL/kg形成急性肺损伤模型;毛蒟挥发油组大鼠在油酸造模前30分钟静脉注射毛蒟挥发油;建模4 h后处死,留取标本。观察各组肺组织病理学形态并进行肺损伤评分,同时测定血气分析值、右下肺湿干重、肺通透指数以及肺泡灌洗液中TNF-α、IL-6和IL-1β炎症因子的含量,最后采用免疫组化和Western Blot检测p38MAPK和p-p38MAPK蛋白的表达量。结果表明大鼠PaO_2和PaO_2/FiO_2在油酸模型组明显低于对照组,同时右下肺湿干重、肺通透指数以及肺泡灌洗液中TNF-α、IL-6和IL-1β炎症因子的含量在油酸模型组明显高于对照组。油酸模型组肺组织病理学显示肺损伤明显;毛蒟挥发油组上述指标较油酸模型组明显减轻。p-p38MAPK蛋白表达量在油酸模型组中明显高于对照组,而p-p38MAPK蛋白表达量在毛蒟挥发油组中明显低于油酸模型组。实验证明黔产毛蒟挥发油能够通过抑制p38MAPK通路减少急性肺损伤炎症因子的产生,对急性肺损伤具有较好的保护作用。     

右美托咪定后处理对胸部撞击-失血性休克和复苏致急性肺损伤的影响

为探讨右美托咪定后处理对胸部撞击失血性休克和复苏致急性肺损伤的影响。本研究选取45只SPF级雄性健康大鼠依据随机数字表法将其分为3组,生理盐水组、THSR组(胸部撞击-失血性休克/复苏组)和治疗组(右美托咪定后处理组),THSR组和治疗组制备胸部撞击-失血性休克/复苏致急性肺损伤模型,治疗组模型建立后静脉注射右美托咪定10μg/kg。模型制备6 h后采血,并处死大鼠。比较3组大鼠血气分析指标(PaO_2,PaCO_2和氧合指数(OI))、肺组织病理形态、炎症因子水平(血浆IL-6和IL-1β水平,肺泡灌洗液(BALF)中蛋白浓度和白细胞数目)以及肺组织中TLR4和p-p38MAPK表达水平。与生理盐水组比较,THSR组和治疗组的PaO_2升高(p0.05),OI降低(p0.05),THSR组PaCO_2升高(p0.05),THSR组和治疗组的PaO_2、PaCO_2和OI差异具有统计学意义(p0.05);THSR组疗组大鼠肺组织病理学损伤评分、血浆炎症因子(BLAF蛋白,白细胞计数,IL-6和IL-1β)水平最高,治疗组次之,生理盐水组最低(p0.05);THSR组和治疗组大鼠肺组织中TLR4和p-p38MAPK表达较生理盐水组上调(p0.05),治疗组大鼠肺组织中TLR4和p-p38MAPK表达水平较THSR组显著下调(p0.05)。右美托咪定后处理可明显减轻胸部撞击-失血性休克和复苏致急性肺损伤,其起效机制可能与抑制TLR4/p-p38MAPK信号通路激活,降低机体炎性反应有关。     

绿原酸对小鼠急性肺损伤的保护作用研究

本文探讨了绿原酸对补体旁路激活致小鼠急性肺损伤的保护作用及可能的作用机制。将32只KM小鼠随机分为正常对照组、模型组、白藜芦醇组、绿原酸组,预防给药7 d后,用特异性补体旁路激活蛋白眼镜蛇毒因子(CVF)尾静脉注射复制小鼠急性肺损伤模型。测定肺含水量、肺组织匀浆中髓过氧化物酶(MPO)活性、支气管肺泡灌洗液(BALF)中细胞数目和蛋白含量,ELISA法检测BALF和血清中白介素-6(IL-6)、肿瘤坏死因子(TNF-α)、P选择素(P-selectin)和细胞间黏附分子-1(ICAM-1)的含量,HE染色法观察肺组织病理形态学变化,免疫组化法测定肺组织中NF-κB p65的磷酸化水平。研究发现,绿原酸可以降低小鼠BALF中蛋白含量、炎性细胞数目、IL-6和TNF-α含量以及肺组织匀浆中MPO活性,并可显著降低血清中IL-6、TNF-α及P-selectin、ICAM-1水平;病理形态学显示绿原酸可以显著抑制炎性细胞浸润,免疫组化结果显示绿原酸可显著抑制小鼠NF-κB p65的磷酸化水平。以上结果说明绿原酸可明显减轻补体旁路激活诱导的小鼠急性肺损伤,其机制可能与抑制NF-κB p65的磷酸化及降低炎症反应程度有关。     

齐墩果酸抑制肿瘤坏死因子-α诱导的成纤维细胞样滑膜细胞炎症因子表达及其机制研究

探讨齐墩果酸(Oleanolic acid,OA)对肿瘤坏死因子-α(TNF-α)诱导成纤维细胞样滑膜细胞的炎症因子表达的影响及其机制。首先复苏培养人成纤维细胞样滑膜细胞(FLS),通过RT-PCR检测细胞IL-6及IL-1βmRNA表达,采用Western blot方法检测p38MAPK及NF-κB蛋白表达变化,通过ELISA法检测细胞上清液中IL-6及IL-1β浓度。与对照组比较,TNF-α明显诱导FLS细胞IL-6及IL-1βmRNA的表达及上清液中IL-6及IL-1β的分泌(P0.05),同时磷酸化p38蛋白和核NF-κB明显增加(P0.05),且p38MAPK阻断剂SB203580能抑制TNF-α诱导的核NF-κB增加。OA呈浓度依赖性抑制TNF-α诱导的FLS细胞p38蛋白磷酸化和核NF-κB增加(P0.05)。且OA、p38MAPK通路抑制剂SB203580或NF-κB阻断剂BAY 11-7082均能抑制TNF-α诱导的IL-6及IL-1β分泌增加(P0.05)。综上所述,OA能抑制TNF-α诱导的FLS细胞炎症因子IL-6及IL-1β的产生,其机制可能与抑制p38MAPK/NF-κB信号通路有关。     

绿茶多酚对兔主动脉粥样硬化斑块中磷酸化p38MAPK的影响

探讨绿茶多酚(GTP)对动脉粥样硬化(AS)兔主动脉粥样硬化斑块中磷酸化p38MAPK的影响。将雄性纯种新西兰大白兔随机分为3组:对照组、AS组和GTP+AS组。用组织病理学和血管超声检查评价建模情况,Western blot检测p38 MAPK磷酸化水平,应用酶联免疫法检测TNF-α的水平。与对照组比较,AS组TNF-α水平和p38MAPK磷酸化水平增高(P0.01),给予GTP干预后,TNF-α水平和p38MAPK磷酸化水平降低(P0.01)。GTP有延缓AS斑块进展,抑制炎症反应的作用,其机制与阻断p38 MAPK通路的活化有关。     

三七皂苷单体Rg1对低氧高二氧化碳肺动脉平滑肌细胞p38MAPK表达的影响

目的:研究三七皂苷单体Rg1对低氧高二氧化碳肺动脉平滑肌细胞(PASMCs)p38MAPK表达的影响。方法:分离、纯化SD大鼠PASMCs,实验用2至5代细胞,实验分六组:常氧组(N组),低氧高二氧化碳组(H组),DM-SO对照组(HD组),Rg1干预组(RgL、RgM、RgH组)。采用Western blot检测磷酸化p38MAPK蛋白表达,RT-PCR检测p38MAPK mRNA的表达。结果:Westernblot、RT-PCR结果显示,HD组p-p38MAPK蛋白和p38MAPK mRNA表达明显高于N组(P<0.01),RgL、RgM、RgH组不同程度抑制了p-p38MAPK蛋白和p38MAPK mRNA和的表达(P<0.01),并呈剂量依赖关系。结论:三七皂苷单体Rg1对低氧高二氧化碳条件下PASMCs有保护作用,其机制可能与抑制p38MAPK的表达有关。     

Acute ventilator-induced vascular permeability and cytokine responses in isolated and in situ mouse lungs.

To determine the influence of experimental model and strain differences on the relationship of vascular permeability to inflammatory cytokine production after high peak inflation pressure (PIP) ventilation, we used isolated perfused mouse lung and intact mouse preparations of Balb/c and B6/129 mice ventilated at high and low PIP. Filtration coefficients in isolated lungs and bronchoalveolar lavage (BAL) albumin in intact mice increased within 20-30 min after initiation of high PIP in isolated Balb/c lungs and intact Balb/c, B6/129 wild-type, and p55 and p75 tumor necrosis factor (TNF) dual-receptor null mice. In contrast, the cytokine response was delayed and variable compared with the permeability response. In isolated Balb/c lungs ventilated with 25-27 cmH(2)O PIP, TNF-alpha, interleukin (IL)-1 beta, IL-1 alpha, macrophage inflammatory protein (MIP)-2, and IL-6 concentrations in perfusate were markedly increased in perfusate at 2 and 4 h, but only MIP-2 was detectable in intact Balb/c mice using the same PIP. In intact wild-type and TNF dual-receptor null mice with ventilation at 45 cmH(2)O PIP, the MIP-2 and IL-6 levels in BAL were significantly increased after 2 h in both groups, but there were no differences between groups in the BAL albumin and cytokine concentrations or in lung wet-to-dry weight ratios. TNF-alpha was not be detected in BAL fluids in any group of intact mice. These results suggest that the alveolar hyperpermeability induced by high PIP ventilation occurs very rapidly and is initially independent of TNF-alpha participation and unlikely to depend on MIP-2 or IL-6.     

Chest wall restriction limits high airway pressure-induced lung injury in young rabbits

High peak inspiratory pressures (PIP) during mechanical ventilation can induce lung injury. In the present study we compare the respective roles of high tidal volume with high PIP in intact immature rabbits to determine whether the increase in capillary permeability is the result of overdistension of the lung or direct pressure effects. New Zealand White rabbits were assigned to one of three protocols, which produced different degrees of inspiratory volume limitation: intact closed-chest animals (CC), closed-chest animals with a full-body plaster cast (C), and isolated excised lungs (IL). The intact animals were ventilated at 15, 30, or 45 cmH2O PIP for 1 h, and the lungs of the CC and C groups were placed in an isolated lung perfusion system. Microvascular permeability was evaluated using the capillary filtration coefficient (Kfc). Base-line Kfc for isolated lungs before ventilation was 0.33 +/- 0.31 ml.min-1.cmH2O-1.100g-1 and was not different from the Kfc in the CC group ventilated with 15 cmH2O PIP. Kfc increased by 850% after ventilation with only 15 cmH2O PIP in the unrestricted IL group, and in the CC group Kfc increased by 31% after 30 cmH2O PIP and 430% after 45 cmH2O PIP. Inspiratory volume limitation by the plaster cast in the C group prevented any significant increase in Kfc at the PIP values used. These data indicate that volume distension of the lung rather than high PIP per se produces microvascular damage in the immature rabbit lung.     

Phosphoinositide 3-kinase, Src, and Akt modulate acute ventilation-induced vascular permeability increases in mouse lungs

To determine the role of phosphoinositide 3-OH kinase (PI3K) pathways in the acute vascular permeability increase associated with ventilator-induced lung injury, we ventilated isolated perfused lungs and intact C57BL/6 mice with low and high peak inflation pressures (PIP). In isolated lungs, filtration coefficients (K(f)) increased significantly after ventilation at 30 cmH(2)O (high PIP) for successive periods of 15, 30 (4.1-fold), and 50 (5.4-fold) min. Pretreatment with 50 microM of the PI3K inhibitor, LY-294002, or 20 microM PP2, a Src kinase inhibitor, significantly attenuated the increase in K(f), whereas 10 microM Akt inhibitor IV significantly augmented the increased K(f). There were no significant differences in K(f) or lung wet-to-dry weight (W/D) ratios between groups ventilated with 9 cmH(2)O PIP (low PIP), with or without inhibitor treatment. Total lung beta-catenin was unchanged in any low PIP isolated lung group, but Akt inhibition during high PIP ventilation significantly decreased total beta-catenin by 86%. Ventilation of intact mice with 55 cmH(2)O PIP for up to 60 min also increased lung vascular permeability, indicated by increases in lung lavage albumin concentration and lung W/D ratios. In these lungs, tyrosine phosphorylation of beta-catenin and serine/threonine phosphorylation of Akt, glycogen synthase kinase 3beta (GSK3beta), and ERK1/2 increased significantly with peak effects at 60 min. Thus mechanical stress activation of PI3K and Src may increase lung vascular permeability through tyrosine phosphorylation, but simultaneous activation of the PI3K-Akt-GSK3beta pathway tends to limit this permeability response, possibly by preserving cellular beta-catenin.     

Time and pressure dependence of transvascular Clara cell protein, albumin, and IgG transport during ventilator-induced lung injury in mice

We compared the transport of three proteins with different hydrodynamic radii with ultrastructural changes in lungs of intact mice ventilated at peak inflation pressures (PIP) of 15, 35, 45, and 55 cmH(2)O for 2 h and PIP of 55 cmH(2)O for 0.5 and 1 h. After 2 h of ventilation, significant increases were observed in plasma Clara cell secretory protein (1.9 nm radius) at 35 cmH(2)O PIP and in bronchoalveolar lavage fluid albumin (3.6 nm radius) at 45 cmH(2)O PIP and IgG (5.6 nm radius) at 55 cmH(2)O PIP. Increased concentrations of all three proteins and lung wet-to-dry weight ratios were significantly correlated with PIP and ventilation time. Clara cell secretory protein and albumin increased significantly after 0.5 h of 55 cmH(2)O PIP, but IgG increased only after 2 h. Separation of endothelium or epithelium to form blebs was apparent only in small vessels (15-30 microm diameter) at 45 cmH(2)O PIP and after 0.5 h at 55 cmH(2)O PIP but became extensive after 2 h of ventilation at 55 cmH(2)O PIP. Junctional gaps between cells were rarely observed. Ultrastructural lung injury and protein clearances across the air-blood barrier were related to ventilation time and PIP levels. Protein clearances increased in relation to molecular size, consistent with increasing dimensions and frequency of transmembrane aqueous pathways.     

Lack of matrix metalloproteinase-9 worsens ventilator-induced lung injury

Matrix metalloproteinase-9 (MMP-9) is released by neutrophils at the sites of acute inflammation. This enzyme modulates matrix turnover and inflammatory response, and its activity has been found to be increased after ventilator-induced lung injury. To clarify the role of MMP-9, mice lacking this enzyme and their wild-type counterparts were ventilated for 2 h with high- or low-peak inspiratory pressures (25 and 15 cmH2O, respectively). Lung injury was evaluated by gas exchange, respiratory mechanics, wet-to-dry weight ratio, and histological analysis. The activity of MMP-9 and levels of IL-1beta, IL-4, and macrophage inflammatory protein (MIP-2) were measured in lung tissue and bronchoalveolar lavage fluid (BALF). Cell count and myeloperoxidase activity were measured in BALF. There were no differences between wild-type and Mmp9-/- animals after low-pressure ventilation. After high-pressure ventilation, wild-type mice exhibited an increase in MMP-9 in tissue and BALF. Mice lacking MMP-9 developed more severe lung injury than wild-type mice, in terms of impaired oxygenation and lung mechanics, and higher damage in the histological study. These effects correlated with an increase in both cell count and myeloperoxidase activity in the BALF, suggesting an increased neutrophilic influx in response to ventilation. An increase in IL-1beta and IL-4 in the BALF only in knockout mice could be responsible for the differences. There were no differences between genotypes in MMP-2, MMP-8, or tissue inhibitors of metalloproteinases. These results show that MMP-9 protects against ventilator-induced lung injury by decreasing alveolar neutrophilic infiltration, probably by modulation of the cytokine response in the air spaces.     

参麦注射液对肠缺血/再灌注肺损伤大鼠肺组织p38MAPK及凋亡相关基因表达的影响

目的:观察参麦注射液(SM)对肠缺血/再灌注(I/R)肺损伤大鼠肺组织p38MAPK和凋亡相关基因Bax、Bcl-2蛋白表达的影响,探讨其保护机制。方法:采用夹闭肠系膜上动脉(SMA)方法建立大鼠肠I/R损伤模型。24只SD大鼠随机分为对照组(Control组)、肠缺血/再灌注组(I/R组)、参麦注射液组(SM+I/R组),每组8只。比较各组大鼠肺湿/干比(W/D)、肺表面活性物质主要成分卵磷脂(PC)及总磷脂(TPL)含量的变化;同时免疫组织化学法检测各组大鼠肺组织中p38MAPK、Bax及Bcl-2蛋白的表达水平。结果:与对照组比较,I/R组肺组织W/D明显升高,而PC和TPL的含量显著降低,肺组织p38MAPK、Bcl-2和Bax蛋白表达明显增强(P均＜0.01),其中Bax的增强比Bcl-2的增强更为明显,Bcl-2/Bax比值降低(P＜0.01);与I/R组比较,SM+I/R组大鼠肺组织W/D明显降低,PC和TPL的含量增加,肺组织p38MAPK和Bax蛋白表达下降(P均＜0.01),Bcl-2的表达增强,Bcl-2/Bax比值明显升高(P＜0.01)。相关分析显示,肠I/R时肺组织p38MAPK蛋白表达水平与肺表面活性物质主要功能成分PC含量及凋亡基因Bcl-2/Bax比值呈负相关(r分别为-0.787,-0.731,P均＜0.01)。结论:SM可能通过抑制p38MAPK信号通路的激活,提高Bcl-2/Bax比值来阻抑细胞凋亡,从而减轻肠I/R时的肺损伤。     

褪黑素对内毒素致大鼠急性肺损伤的保护作用

目的:研究内毒素(LPS)致大鼠急性肺损伤(ALI)时,p-p38蛋白激酶(p-p38MAPK)在肺组织的表达及褪黑素(MT)对肺组织的保护作用及其机制。方法:将72只健康雄性SD大鼠随机分为3组,每组24只,对照组(Control)、模型组(LPS)和褪黑素干预组(LPS+MT),采用气管内滴注LPS的方法建立大鼠ALI的模型,通过免疫组织化学染色和Western blot技术检测大鼠肺组织中p-p38蛋白激酶的表达变化,并在光镜下观察大鼠肺组织形态学变化。结果:Control组气道和肺组织可见反应极弱的p-p38蛋白激酶阳性细胞,散在分布于气道上皮细胞和肺泡上皮细胞;LPS组p-p38蛋白激酶阳性细胞较对照组明显增多(P0.05或P0.01),主要分布于浸润的炎症细胞、气道上皮细胞、肺泡上皮细胞和血管内皮细胞;LPS+MT组气道和肺组织中阳性细胞数较LPS组明显减少(P0.05或P0.01),Western blot结果与免疫组织化学一致。结论:LPS致大鼠急性肺损伤模型中,肺内炎性、非炎性细胞均有p38MAPK信号通路的激活;MT对急性肺损伤的保护机制可能与其抑制p38 MAPK信号通路的过度激活有关。     

Effect of lung-protective ventilation on severe Pseudomonas aeruginosa pneumonia and sepsis in rats

Pneumonia caused by Pseudomonas aeruginosa carries a high rate of morbidity and mortality. A lung-protective strategy using low tidal volume (V(T)) ventilation for acute lung injury improves patient outcomes. The goal of this study was to determine whether low V(T) ventilation has similar utility in severe P. aeruginosa infection. A cytotoxic P. aeruginosa strain, PA103, was instilled into the left lung of rats anesthetized with pentobarbital. The lung-protective effect of low V(T) (6 ml/kg) with or without high positive end-expiratory pressure (PEEP, 10 or 3 cmH(2)O) was then compared with high V(T) with low PEEP ventilation (V(T) 12 ml/kg, PEEP 3 cmH(2)O). Severe lung injury and septic shock was induced. Although ventilatory mode had little effect on the involved lung or septic physiology, injury to noninvolved regions was attenuated by low V(T) ventilation as indicated by the wet-to-dry weight ratio (W/D; 6.13 +/- 0.78 vs. 3.78 +/- 0.26, respectively) and confirmed by histopathological examinations. High PEEP did not yield a significant protective effect (W/D, 4.03 +/- 0.32) but, rather, caused overdistension of noninvolved lungs. Bronchoalveolar lavage revealed higher concentrations of TNF-alpha in the fluid of noninvolved lung undergoing high V(T) ventilation compared with those animals receiving low V(T). We conclude that low V(T) ventilation is protective in noninvolved regions and that the application of high PEEP attenuated the beneficial effects of low V(T) ventilation, at least short term. Furthermore, low V(T) ventilation cannot protect the involved lung, and high PEEP did not significantly alter lung injury over a short time course.