巨噬细胞炎症蛋白-1α在机械通气致大鼠急性肺损伤中的作用

目的 观察巨噬细胞炎症蛋白-1α(MIP-1α)在不同潮气量机械通气致大鼠急性肺损伤发病中的作用.方法 24只雄性健康Wistar大鼠随机分为对照组、小潮气量组和大潮气量组.分别检测各组大鼠支气管肺泡灌洗液(BALF)中性粒细胞计数、BALF和血浆髓过氧化物酶(MPO)活性和MIP-1α含量以及肺组织MIP-1α蛋白表达水平.结果 大潮气量组大鼠BALF中性粒细胞计数、MPO活性及MIP-1α含量均明显高于对照组和小潮气量组(P值均<0.01).大潮气量组大鼠肺泡上皮和细支气管上皮细胞MIP-1α蛋白表达水平明显高于对照组和小潮气量组(P值均<0.01).对照组与小潮气量组各项指标比较差异无统计学意义.相关分析结果表明,各组大鼠BALF中MIP-1α含量与中性粒细胞计数及MPO活性均呈正相关(r=0.803,r=0.791,P值均<0.05).结论 趋化性细胞因子MIP-1α促使中性粒细胞在肺内募集、活化是导致呼吸机所致肺损伤发病的重要因素之一;呼吸机所致肺损伤病变部位不仅仅局限于肺泡,对细支气管也有一定损伤作用.     

人IL-10对呼吸机相关性肺损伤大鼠炎性细胞因子的影响

目的：探讨人白介素10(hIL-10)预先给药对呼吸机相关性肺损伤(VILI)大鼠炎性因子的影响。方法健康雄性 SD大鼠36只,体质量220~300 g,随机分为3组(n=12)：对照组(C组)、大潮气量机械通气组(H 组)和 hIL-10干预组(HI组)。其中C组经口插管后维持自主呼吸4 h;H 组采用大潮气量机械通气建立大鼠 VILI 模型,阿曲库铵静脉输注抑制自主呼吸、维持肌松,接小动物呼吸机机械通气,呼吸参数设定：呼吸频率40次/min,通气时间4 h,吸呼比为1∶3,呼气末正压通气0 cmH2 O,吸入氧浓度为21%,潮气量30 ml/kg,根据体质量调节潮气量;HI组在大潮气量机械通气开始前30 min从尾静脉注射 hIL-10(剂量为8000 U/kg),余同 H 组,C组、H 组给予等量的生理盐水。各组于通气4 h后放血处死大鼠,收集大鼠血清和 BALF,采用酶联免疫吸附测定法检测肿瘤坏死因子α(TNF-α)、IL-8和细胞间黏附分子1(ICAM-1)的浓度;取右上肺组织做病理切片,HE染色镜下观察形态学变化。结果光镜下观察显示 C组肺泡结构无明显损伤;H 组肺泡结构破坏严重,肺泡内渗出物、出血和间质水肿明显,可见明显肺泡腔融合,肺间隔增宽,大量炎性细胞浸润;HI组肺组织结构有一定程度损伤,肺间隔有少量增厚,但较 H 组减轻。与C组相比,H 组、HI组血清和BALF中TNF-α、IL-8和 ICAM-1水平均升高(P <0.05或 P <0.01);与 H 组相比, HI组血清和BALF中TNF-α、IL-8和 ICAM-1水平明显降低(P值均<0.01)。结论 hIL-10作为机体重要的抗炎因子,可通过调节肺组织炎症反应,降低炎性细胞因子水平,在一定程度上减轻大鼠VILI。     

不同潮气量通气对内毒素肺损伤大鼠Th1/Th2平衡的影响

目的 探讨内毒素肺损伤Thl/Th2平衡变化及不同潮气量通气对内毒素肺损伤大鼠Thl/Th2平衡的影响。方法 健康大鼠32只随机分成4组：生理盐水正常对照A组、内毒素肺损伤非机械通气B组、内毒素肺损伤＋小潮气量C组、内毒素肺损伤＋传统潮气量D组。监测平均动脉压(MAP)、心率(HR)，计算氧合指数（OI），检测PBMC中IFN-γ、IL-4浓度水平并计算IFN-γ/IL-4。取右肺中叶计算肺组织湿干比值(W/D)；观察右肺下叶肺组织病理变化；分析支气管肺泡灌洗液(BALF)中白细胞(WBC)与中性粒细胞(PMN)。结果 1. B、C、D组OI、W/D及病理学变化符合急性肺损伤表现；2. B组IFN-γ/IL-4比值明显高于A组；C组IFN-γ/IL-4比值明显低于B组；D组IFN-γ/IL-4比值明显高于B组；3. B组肺W/D及BALF中WBC、PMN计数明显高于A组；C组肺W/D及BALF中WBC、PMN计数明显低于B组；D组肺W/D及BALF中WBC、PMN计数明显高于B组。结论 1.注射LPS可成功复制大鼠急性肺损伤动物模型；2.内毒素致大鼠肺损伤早期，其PBMC中IFN-γ和IL-4浓度增加，IFN-γ/IL-4升高，Thl/Th2失衡；3.传统潮气量机械通气可加重内毒素肺损伤大鼠炎症反应，使肺损伤早期大鼠Th1/Th2失衡加剧；4.保护性通气策略的小潮气量机械通气可减轻内毒素肺损伤大鼠PMN在肺内“扣押”，改善Th1/Th2失衡状态。     

不同潮气量通气对内毒素肺损伤大鼠Th1/Th2淋巴细胞平衡的影响

目的:探讨不同潮气量通气对内毒素肺损伤大鼠Th1/Th2淋巴细胞平衡的影响。方法:健康大鼠32只,随机分成4组:生理盐水正常对照组(A组)、内毒素肺损伤非机械通气组(B组)、内毒素肺损伤+小潮气量组(C组)、内毒素肺损伤+传统潮气量组(D组)。监测平均动脉压(MAP)、心率(HR),计算氧合指数(OI),检测外周血单核细胞(PBMC)中IFN-γ、IL-4浓度并计算IFN-γ/IL-4。取右肺中叶计算肺组织湿干比值(W/D);观察右肺下叶肺组织病理变化;分析支气管肺泡灌洗液(BALF)中白细胞(WBC)与中性粒细胞(PMN)计数。结果:B、C、D组OI、W/D及病理学变化符合急性肺损伤表现。B组IFN-γ/IL-4比值、肺W/D及BALF中WBC、PMN计数明显高于A组与C组,但低于D组。结论:①注射内毒素可成功复制大鼠急性肺损伤动物模型;②内毒素致大鼠肺损伤早期,其PBMC中IFN-γ和IL-4浓度增加,IFN-γ/IL-4比值升高,Th1/Th2淋巴细胞失衡;③传统潮气量机械通气可加重内毒素肺损伤大鼠炎症反应,使肺损伤早期大鼠Th1/Th2淋巴细胞失衡加剧;④保护性通气策略的小潮气量机械通气可减轻内毒素肺损伤大鼠PMN在肺内"扣押",改善Th1/Th2淋巴细胞失衡状态。     

瘦素预处理对机械通气肺损伤大鼠NLRC4炎症小体表达的影响

目的:探讨瘦素预处理对机械通气肺损伤(VILI)大鼠NLRC4炎症小体表达的影响。方法:健康雄性SD大鼠36只,体质量200～250 g,6～8周龄,采用随机数字表法分为3组：对照组、VILI模型组和瘦素组,每组12只。对照组麻醉后气管插管并保留自主呼吸;VILI模型组连接小动物呼吸机行机械通气,潮气量40 ml/kg...     

卡托普利对大潮气量机械通气大鼠肺组织细胞凋亡的影响

目的 通过观察大潮气量机械通气大鼠肺组织细胞凋亡水平和肺内血管紧张素Ⅱ(AngⅡ)含量的变化,探讨血管紧张素转换酶抑制剂——卡托普利对呼吸机所致肺损伤(VILI)的防治作用.方法 雄性Wistar大鼠30只,随机分为对照组、大潮气量机械通气组(H-VT)和卡托普利干预组(CAP).观察各组大鼠肺组织病理学改变,测定其急性肺损伤(ALI)评分、支气管肺泡灌洗液(BALF)总蛋白含量和肺湿/干重比值(W/D).采用DNA断端末端标记法(TUNEL)检测肺组织细胞凋亡指数,采用ELISA法检测肺组织AngⅡ含量.结果 H-VT组大鼠肺组织ALI评分、W/D,BALF总蛋白含量、肺组织AngⅡ含量及细胞凋亡指数均明显高于对照组(P值均＜0.01),且出现明显肺组织病理学改变.CAP组大鼠肺组织上述指标均较H-VT组明显降低(.P值均＜0.01),同时肺组织病理学改变也较H-Vr组明显减轻.结论 肺组织细胞凋亡在VILI发病中具有重要作用,卡托普利可通过降低大潮气量机械通气大鼠肺组织细胞凋亡水平,对V1LI起一定保护作用.     

高容量通气对兔肺组织肿瘤坏死因子-α、白介素-1β、转化生长因子-β1表达的作用

目的:探讨高容量机械通气对大白兔肺组织TNF-α、IL-1β、TGF-β1的作用.方法:将30只3月龄雄性大白兔随机分成3组:对照组、常规潮气量组及大潮气量组,每组各10只.对照组插管后不机械通气,另2组插管后机械通气.常规潮气量组VT8 mL/kg,大潮气量组VT 25 mL/kg,其它参数相同,通气时间24 h.观察实验前后动脉血pH值、PaO2及PaCO2的变化、ELISA法测定肺组织TNF-α、IL-1β,SABC法测定TGF-β1、测定肺组织湿/干重(W/D)值、观察肺组织病理学变化.结果:与对照组比较,大潮气量组通气24 h后动脉血pH、PaO2和PaCO2变化显著(均P＜0.05),肺组织W/D、TNF-α、IL-1β、TGF-β1升高(均P＜0.01),肺组织水肿,常规潮气量组相应指标无显著变化(P＞0.05).结论:大潮气量机械通气易发生呼吸机相关性肺损伤(VILI),表现为动脉氧分压、肺组织W/D、肺组织病理变化,同时肺组织TNF-α、IL-1β、TGF-β1升高,表明VILI与TNF-α、IL-1β、TGF-β1炎性细胞因子有关.     

不同潮气量机械通气对大鼠肺组织Clara细胞分泌蛋白及分泌型磷脂酶A2的影响

目的 通过观察不同潮气量机械通气大鼠肺组织Clara细胞分泌蛋白(CC16)及分泌型磷脂酶A2(sPLA2)的表达,探讨CC16和sPLA2在呼吸机所致肺损伤(VILI)发生中的作用.方法 24只雄性Wistar大鼠随机分为对照组、小潮气量组和大潮气量组,测定各组大鼠支气管肺泡灌洗液(BALF)总蛋白含量及中性粒细胞计数,采用免疫组织化学染色法检测肺组织Clara细胞计数和CC16蛋白表达,采用逆转录聚合酶链反应法检测肺组织sPLA2 mRNA的表达.结果 大潮气量组大鼠BALF总蛋白含量、中性粒细胞的计数和肺组织sPLA2 mRNA表达水平均明显高于对照组和小潮气量组(P值均＜0.01),而肺组织Clara细胞计数和CC16蛋白表达水平则明显低于对照组和小潮气量组(P值均＜0.01);小潮气量组各项指标与对照组比较差异无统计学意义(P＞0.05).结论 大潮气量机械通气通过诱导肺组织sPLA2 mRNA高表达,使Clara细胞合成及分泌CC16减少,导致肺组织炎症反应扩大,可能是VILI发生的重要因素之一.     

允许性高碳酸血症的器官保护及应用策略

急性肺损伤（ALI）/急性呼吸窘迫综合征（ARDS）是临床常见的急危重病。目前,机械通气（MV）仍是其主要治疗手段之一。MV在改善机体通气、氧合的同时可导致或加重肺损伤,形成呼吸机相关性肺损伤（VILI）,而采取减小潮气量和适当提高呼气末正压（PEEP）水平的肺保护通气策略可提高ALI/ARDS患者生存率[1]。     

Contribution of high-mobility group box-1 to the development of ventilator-induced lung injury

RATIONALE: Proinflammatory cytokines play an important role in ventilator-induced lung injury (VILI). High-mobility group box-1 (HMGB1) is a macrophage-derived proinflammatory cytokine that can cause lung injury. OBJECTIVES: This study tested the hypothesis that HMGB1 is released in intact lungs ventilated with large Vt. A second objective was to identify the source of HMGB1. A third objective was to examine the effects of blocking HMGB1 on the subsequent development of VILI. METHODS: Bronchoalveolar lavage fluid (BALF) and lung tissues were obtained from rabbits mechanically ventilated for 4 h with a small (8 ml/kg) versus a large (30 ml/kg) Vt. BALF was also obtained from rabbits with intratracheal instillation of anti-HMGB1 antibody before the initiation of large Vt ventilation. MEASUREMENTS AND MAIN RESULTS: The concentrations of HMGB1 in BALF were fivefold higher in the large than in the small Vt group. Immunohistochemistry and immunofluorescence studies revealed expression of HMGB1 in the cytoplasm of macrophages and neutrophils in lungs ventilated with large Vt. Blocking HMGB1 improved oxygenation, limited microvascular permeability and neutrophil influx into the alveolar lumen, and decreased concentrations of tumor necrosis factor-alpha in BALF. CONCLUSIONS: These observations suggest that HMGB1 could be one of the deteriorating factors in the development of VILI.     

Pre-treatment with mesenchymal stem cells reduces ventilator-induced lung injury

Bone marrow-derived mesenchymal stem cells (MSCs) reduce acute lung injury in animals challenged by bleomycin or bacterial lipopolysaccaride. It is not known, however, whether MSCs protect from ventilator-induced lung injury (VILI). This study investigated whether MSCs have a potential role in preventing or modulating VILI in healthy rats subjected to high-volume ventilation. 24 Sprague-Dawley rats (250-300 g) were subjected to high-volume mechanical ventilation (25 mL·kg(-1)). MSCs (5×10(6)) were intravenously or intratracheally administered (n=8 each) 30 min before starting over-ventilation and eight rats were MSC-untreated. Spontaneously breathing anesthetised rats (n=8) served as controls. After 3 h of over-ventilation or control the animals were sacrificed and lung tissue and bronchoalveolar lavage fluid (BALF) were sampled for further analysis. When compared with controls, MSC-untreated over-ventilated rats exhibited typical VILI features. Lung oedema, histological lung injury index, concentrations of total protein, interleukin-1β, macrophage inflammatory protein-2 and number of neutrophils in BALF and vascular cell adhesion protein-1 in lung tissue significantly increased in over-ventilated rats. All these indices of VILI moved significantly towards normalisation in the rats treated with MSCs, whether intravenously or intratracheally. Both local and systemic pre-treatment with MSCs reduced VILI in a rat model.     

Adenosine triphosphate-dependent calcium signaling during ventilator-induced lung injury is amplified by hypercapnia

Adenosine triphosphate (ATP) is released by alveolar epithelial cells during ventilator-induced lung injury (VILI) and regulates fluid transport across epithelia. High CO(2) levels are observed in patients with "permissive hypercapnia," which inhibits alveolar fluid reabsorption (AFR) in alveolar epithelial cells. The authors set out to determine whether VILI affects AFR and whether the purinergic pathway is modulated in cells exposed to hypercapnia. Control group was compared against VILI (tidal volume [Vt] = 35 mL/kg, zero positive end-expiratory pressure [PEEP]) and protective ventilation (Vt = 6 mL/kg, PEEP = 10 cm H(2)O) groups. Lung mechanics, histology, and AFR were evaluated. Alveolar epithelial cells (AECs) were loaded with Fura 2-AM to measure intracellular calcium in the presence ATP (10 μM) at 5% or 10% CO(2) as compared with baseline. High tidal volume ventilation impairs lung mechanics and AFR. Hypercapnia (HC) increases intracellular calcium levels in response to ATP stimulation. HC + ATP is the most detrimental combination decreasing AFR. Purinergic signaling in AECs is modulated by high CO(2) levels via increased cytosolic calcium. The authors reason that this modulation may play a role in the impairment of alveolar epithelial functions induced by hypercapnia.     

肺表面活性物质异常在呼吸机所致肺损伤发生中作用的实验研究

目的 探讨肺表面活性物质(PS)异常在呼吸机所致肺损伤(VILI)发生中的作用.方法 40只成年SD大鼠随机分成5组,每组8只,对照组于手术完毕后处死,其余4组给予机械通气(MV)(1)P7组,设置吸气峰压(cmH2O)/频率(次/min)/吸呼比/呼气末正压(PEEP)(cm H2O)为7/40/11/0;(2)P45组,45/20/11/0;(3)PS组,经气道滴入PS100mg/kg,45/20/11/0;(4)PEEP组,45/20/11/10,20min后处死.观察动脉血氧(Pa02)、最大胸肺顺应性(Cmax)、支气管肺泡灌洗液(BALF)的总蛋白(TP)、总磷脂(TPL)、大小聚集体(LA、SA)和最小表面张力(STmin).结果 与P7组比较,P45组Pa02和Cmax均明显降低(P均＜0.01),BALF的TP、SA/LA和STmin显著增加,TPL/TP降低(P均＜0.01).PS组和PEEP组各指标均显著优于P45组(P＜0.05或P＜0.01).P7组和对照组间各指标均相近.结论 VILI时有明显的PS异常;外源性PS和PEEP均可恢复和维持PS结构和功能,减轻VILI,表明PS异常与VILI的发生密切相关.     

Surfactant treatment for ventilation-induced lung injury in rats: effects on lung compliance and cytokines

The objective of this study was to determine if exogenous surfactant therapy could prevent the harmful effects of ventilation at high tidal volumes without positive end-expiratory pressure (PEEP). Rats were randomized to either a nontreated control group (8 mL/kg 4 cm H2O PEEP), a nontreated injuriously ventilated group (20 mL/kg 0 cm H2O PEEP) or a treatment group of either 50 mg/kg, 50 mg/kg + 5% surfactant-associated protein A, 100 mg/kg exogenous surfactant followed by injurious ventilation. Isolated lungs from animals in all 5 groups were ventilated in a humidified box at 37 degrees C for 2 hours. Pressure-volume curves and light microscopy showed that surfactant treatment reduced the ventilation-induced lung injury (VILI). Inflammatory cytokines (tumor necrosis factor-alpha [TNFalpha], interleukin [IL]-1beta, and IL-6) in the lavage were significantly higher in injuriously ventilated lungs compared to the control group. However the 3 treatment groups had cytokine concentrations that were similar to the injuriously ventilated group. We conclude that surfactant treatment is beneficial in preventing VILI; however, it does not prevent the release of inrflammatory cytokines during mechanical ventilation.     

高吸气峰压诱发呼吸机所致肺损伤及呼气末气道正压的保护作用

目的:探讨呼气末气道正压(PEEP)对高吸气峰压(PIP)所致肺损伤的保护作用。方法:20只成年SD大鼠随机分成四组,每组5只,对照组手术完毕后处死,其余三组给予机械通气:1 P10组,设置吸气峰压值为(PIP,cm H2O)/频率(f,次/分)/吸呼比(I:E)/呼气末正压(PEEP,cm H2O)为10/40/1∶1/0;2 P50组,设置PIP/f/I∶E/PEEP为50/20/1∶1/0;3 PEEP组,设置PIP/f/I:E/PEEP为50/40/1;1/10,20分钟后处死。观察呼吸机潮气量(VT)、呼吸系统阻力(Rrs)和动态肺顺应性(Cdyn),测定动脉血氧分压(Pa O2)。实验结束后测定肺组织含气容积密度(VV)、肺髓过氧化物酶(MPO)和白细胞介素-8(IL-8)含量。结果:与P10组比较,P50组VT、Rrs、MPO和IL-8均显著增加(P0.05或P0.01),而Pa O2、Cdyn和VV显著降低(均P0.05);PEEP组上述各指标均显著优于P50组(P0.05或P0.01)。P10和对照组间上述指标均相近。结论:高气道压MV诱发明显VILI,加用PEEP可以保护肺结构和功能,减轻肺损伤。     

家兔呼吸机所致肺损伤HSP70与I-κBα表达的意义

目的:研究在呼吸机所致肺损伤(VILI)的炎症反应中热休克蛋白(HSP70)和核因子抑制蛋白α(I-κBα)表达的意义以及加用呼气末正压(PEEP)的影响。方法:健康成年新西兰白兔30只,随机分为3组,实施麻醉和气管切开术后,分别接受不同潮气量(VT)的通气,通气时间均为4h。对照组(VT=10mL/kg,NVC组),始终以正常条件通气,致伤通气+3cm H2O PEEP(VT=40mL/kg,PEEP=3cm H2O,PEEP组),致伤通气+0cm H2O PEEP(VT=40mL/kg,PEEP=0cm H2O,ZEEP组)。机械通气开始后4h经颈动脉放血处死动物。在光镜下观察肺组织的病理学改变,并采用Western-blot法检测家兔肺组织HSP70及I-κBα的表达。结果:家兔在致伤机械通气4h后,光镜下可见肺组织有不同程度的损伤,肺组织HSP70表达显著增加,且与I-κBα的表达呈正相关,而在致伤机械通气的同时加用PEEP,肺组织的病理损伤明显减轻。结论:HSP70表达增加可能通过阻断I-κBα的降解抑制炎症反应,保护肺组织避免VILI,而在机械通气过程中加用PEEP可使家兔肺组织的病理损伤减轻。     

肺泡复张后不同呼气末正压和潮气量调节策略对防止肺泡再萎陷效果的实验研究

目的探讨肺泡复张(RM)后再萎陷的机制以及呼气末正压(PEEP)和潮气量(VT)的调节策略。方法健康杂种犬18只,建立油酸所致急性呼吸窘迫综合征(ARDS),行容量控制通气(VCV)、PEEP 16 cm H2O、VT10 m l/kg、通气频率(RR)30次/m in,稳定后作为基础状态(0 m in)。以压力控制通气[气道峰压(PIP)50 cm H2O,PEEP 35 cm H2O,持续60 s]行RM,然后随机分为小VT中等PEEP组(LVMP组,VT10 m l/kg、PEEP 16 cm H2O、RR 30次/m in),小VT低PEEP组(LVLP组,VT10 m l/kg、PEEP 10 cm H2O、RR 30次/m in)和中等VT低PEEP组(MVLP组,VT15 m l/kg、PEEP 10cm H2O、RR 20次/m in)。观察4 h后处死动物,行支气管肺泡灌冼。监测氧合、呼吸力学、血流动力学及肺损伤指标。结果(1)LVMP、LVLP、MVLP组低位拐点(LIP)分别为(16.0±1.3)、(15.8±3.0)、(16.3±1.9)cm H2O。(2)在RM后30、60 m in,LVMP组动脉血氧分压(PaO2)[(371±64)、(365±51)mm Hg]显著高于LVLP组[(243±112)、(240±108)mm Hg]及MVLP组[(242±97)、(232±87)mm Hg,P均<0.05],但直至RM后4 h 3组比较差异无统计学意义;LVLP与MVLP组在RM后各个时间点的PaO2与基础状态比较差异均无统计学意义;MVLP组的通气功能较其他两组显著改善。(3)与基础状态比较,RM后LVMP组平均动脉压(mABP)显著降低,平均肺动脉压(mPAP)显著增加,而其他两组mABP保持稳定,mPAP降低。(4)与基础状态比较,3组PIP和气道平台压(Pp lat)在RM后均显著降低,呼吸系统静态顺应性(Cst)显著改善。在RM后同一时间点比较,MVLP组PIP、Pp lat和Cst均显著好于LVMP组。MVLP组与LVLP组相比,Cst有增加趋势。(5)在相同部位的支气管肺泡灌冼液中,肺损伤指标在各组之间无显著差异。结论与LIP相近的高PEEP有助于防止复张肺泡的再萎陷,但对血流动力学和呼吸力学产生不利影响;早期应用RM能有效“节约”PEEP,并为上调VT提供了较肺泡复张之前更大的空间。