慢性阻塞性肺疾病肺血管内皮细胞和肺泡上皮细胞凋亡的实验研究

目的 研究COPD患者及烟雾暴露COPD大鼠肺血管内皮细胞和肺泡上皮细胞凋亡的相互关系及其与肺功能和肺气肿的相关性.方法 采用烟雾暴露法建立COPD大鼠模型.分别采集COPD患者(13例)和对照患者(12例)及烟雾暴露80 d大鼠(11只)和对照大鼠(12只)的肺组织标本,用HE染色评估肺部病理改变,用平均内衬间隔(MLI)与平均肺泡数(MAN)评估大鼠肺气肿程度;用原位末端标记法对肺血管内皮细胞和肺泡上皮细胞凋亡进行定量检测,分析这两种细胞凋亡的相关性,及其与肺功能和肺气肿指标的相关性.正态分布的计量资料以x±s表示,采用两独立样本的t检验进行分析;非正态分布的计量资料以中位数(四分位间距)表示,采用两个独立样本比较的Wilcoxon秩和检验;采用Spearman秩相关进行相关分析.结果 COPD患者和大鼠均出现明显肺气肿病理改变.COPD患者肺血管内皮细胞和肺泡上皮细胞凋亡指数[(13.2±2.6)%和(28.9±3.1)%]明显高于对照患者[(5.6±1.5)%和(5.8±1.2)%].COPD患者肺泡上皮细胞凋亡指数[(28.9±3.1)%]明显高于肺血管内皮细胞凋亡指数[(13.2±2.6)%],二者间呈正相关(r=0.60,P<0.05);COPD患者肺血管内皮细胞和肺泡上皮细胞的凋亡指数与FEV.占预计值%呈负相关(r值分别为-0.83和-0.69,均P<0.05),与FEV1/FVC呈负相关(r值分别为-0.95和-0.71,均P<0.05),与残气容积/肺总量呈正相关(r值分别为0.93和0.70,均P<0.05).COPD大鼠肺血管内皮细胞和肺泡上皮细胞凋亡指数[(4.1±0.4)%和(10.0±1.0)%]明显高于对照大鼠[(0.2±0.1)%和(2.1±0.4)%],COPD大鼠肺组织MLI与肺泡上皮细胞凋亡指数呈正相关(r=0.59,P<0.05),MAN与肺泡上皮细胞凋亡指数呈负相关(r=-0.81,P<0.05).结论 COPD患者和大鼠肺内存在异常的细胞凋亡现象,其肺泡上皮细胞凋亡较肺血管内皮细胞凋亡更为明显,且二者呈正相关;COPD患者和大鼠肺血管内皮细胞和肺泡上皮细胞的凋亡与其肺功能及肺气肿的改变明显相关,推测肺血管内皮细胞和肺泡上皮细胞凋亡可能参与COPD的发病过程.     

Enhanced immediate inflammatory response to Streptococcus pneumoniae in the lungs of mice with pulmonary emphysema

Background and objective:   Pulmonary emphysema is associated with frequent respiratory infections but little is known about the reasons for this susceptibility to bacterial infection. We previously demonstrated an impaired inflammatory response to Streptococcus pneumoniae in an experimental emphysema mouse model at 24 h, or longer following bacterial inoculation. Toll-like receptors (TLR) have been recognized as regulators in the inflammatory response. We examined the expression of TLR on alveolar macrophages in experimental emphysema mice and evaluated the immediate inflammatory response of the emphysematous lung to streptococcal infection.
Methods:   Elastase was administered once into mice trachea to induce pulmonary emphysema. Three weeks later, expression of TLR-2 and TLR-4 in the BAL cells was examined by immunostaining. Following the intratracheal inoculation of Streptococcus pneumoniae , pro-inflammatory cytokine concentrations were measured in the BAL fluids of the control and emphysema mice.
Results:   The expression of TLR-2 and TLR-4 was significantly elevated in the alveolar macrophages of emphysema mice. Six hours after infection, neutrophils in the BAL fluid of emphysema mice were significantly increased, and the levels of tumour necrosis factor-α, IL-1β and IL-6 were significantly elevated, compared with the control mice. At 3 h post inoculation, macrophage inflammatory protein-2 levels were significantly elevated.
Conclusions:   The immediate inflammatory response in the emphysematous lung is significantly enhanced in response to streptococcal infection. This may be partly attributed to the increased expression of TLR in the alveolar macrophages of emphysema mice.     

Oxidant stress mediates inflammation and apoptosis in ventilator-induced lung injury

Background and objective:   Ventilator-induced lung injury (VILI) leads to airway epithelial cell apoptosis and lung inflammation. High tidal volume ventilation in vivo has been shown to induce MIP-2 production, lung neutrophil sequestration and apoptotic airway cell death. This study aimed to determine the effect of N-acetylcysteine (NAC), a scavenger of oxygen radicals, on lung inflammation and apoptosis in an in vivo model of VILI.
Methods:   Sprague–Dawley rats ( n  = 5 per group) were ventilated at low tidal volume (V_T 7 mL/kg) or high tidal volume (V_T 20 mL/kg) with or without administration of 140 mg/kg of intravenous NAC. Animals were ventilated for 30 min, 1 or 2 h, then allowed to recover for 2 h, at which time neutrophil infiltration, MIP-2, TNF-α and IL-6 in BAL fluid, as well as the percentage of apoptotic airway epithelial cells, were measured.
Results:   Ventilation at V_T 20 mL/kg increased oxidant release, as measured by serum isoprostane, and decreased lung glutathione, the major antioxidant in the lung. NAC treatment during ventilation at V_T 20 mL/kg prevented the decrease in lung glutathione and significantly lowered serum isoprostane levels, neutrophil infiltration, cytokines in the BAL and apoptosis in the airways as compared with animals ventilated at V_T 20 mL/kg without NAC ( P  < 0.05).
Conclusions:   These data point to an early role of oxidant-induced inflammation and apoptosis in VILI.     

N-acetylcysteine treatment protects against VEGF-receptor blockade-related emphysema

Administration of the VEGF receptor blocker SU5416 to rats causes alveolar septal cell apoptosis and emphysema; both can be prevented by a superoxide dismutase mimetic. Here we show that SU5416 induces the expression of heme oxygenase-1 in the lung tissue and that administration of antioxidant N-acetyl-l-cysteine protects alveolar septal cells against apoptosis, as demonstrated by caspase-3 lung immunohistochemistry, and against emphysema.     

血管内皮生长因子及其受体在肺气肿患者肺组织中的表达

目的探讨血管内皮生长因子(VEGF)及其受体2(VEGF受体2/KDR)在肺气肿患者肺组织中的表达及其与肺气肿的相关性。方法取35例行肺叶切除术患者[A组(吸烟伴肺气肿组)16例,B组(不吸烟肺功能正常组)14例,C组(吸烟但肺功能正常组)5例]的外周肺组织标本,ELISA法检测肺组织匀浆中VEGF的含量,免疫组化法检测KDR蛋白表达,RT PCR检测VEGF和KDRmRNA水平,TUNEL法检测肺泡隔细胞的凋亡。结果A组患者肺组织VEGF、KDR表达均低于B组(P<0.01),肺泡隔细胞凋亡率高于B组(P<0.01)。C组与B组相比,VEGF及KDR表达差异无统计学意义(P>0.05)。结论VEGF及KDR水平减少与肺泡隔细胞凋亡的增加可能与肺气肿的发生相关。     

N‐Acetylcysteine Treatment Protects Against VEGF‐Receptor Blockade‐Related Emphysema

Administration of the VEGF receptor blocker SU5416 to rats causes alveolar septal cell apoptosis and emphysema; both can be prevented by a superoxide dismutase mimetic. Here we show that SU5416 induces the expression of heme oxygenase‐1 in the lung tissue and that administration of antioxidant N‐acetyl‐l‐cysteine protects alveolar septal cells against apoptosis, as demonstrated by caspase‐3 lung immunohistochemistry, and against emphysema.     

血管内皮生长因子与烟雾暴露所致大鼠肺气肿发病关系的研究

目的　探讨血管内皮生长因子 (VEGF)与烟雾暴露所致大鼠肺气肿发病的关系。方法3 6只 12周龄雌性SD大鼠随机均分为烟雾暴露组 (S组 )和正常对照组 (N组 )。S组随机均分为S1、S2 、S3 组 ,分别烟雾暴露 2、4、8周 ;N组亦随机均分为N1、N2 、N3 组 ,在常氧下再饲养 0、4、8周。分别用逆转录 聚合酶链反应 (RT PCR)和改良的链霉亲合素 生物素 过氧化物酶复合物 (SABC)法检测大鼠肺内VEGFmRNA、VEGF及其受体 2 (KDR ,激酶插入区包含受体 )蛋白表达水平 ;苏木精 伊红 (HE)染色评估S组大鼠肺部病理改变 ,用平均内衬间隔 (MLI)与平均肺泡数 (MAN)评估肺气肿程度。用SPSS10 0进行方差分析、非参数检验和相关性分析。结果　 (1)S组大鼠出现肺部炎症 ,至第 8周 (即S3组 )出现早期肺气肿样改变 ,S3 组的MAN较同时段N3 组显著下降 ,MLI显著增加 (P <0 0 5) ;(2 )S组大鼠肺组织VEGF表达及肺血管内皮细胞KDR表达显著下降 :S1组与N1组比较 ,VEGF189mRNA及肺泡、支气管上皮VEGF蛋白表达下降 (P <0 0 1) ;S2 组与N2 组比较 ,VEGF189、VEGF165、VEGF12 1mRNA及肺泡、支气管上皮VEGF蛋白表达均显著降低 (P <0 0 1) ;S3 组VEGFmRNA表达与N3 组比较差异无显著性 (P >0 0 5) ,但肺泡、支气管上皮细胞VEGF蛋白质表达及     

AP-2α在烟雾暴露所致慢性阻塞性肺疾病大鼠肺组织中的表达及与肺间隔细胞凋亡的关系

目的 探讨熏烟所致慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)大鼠肺组织中AP 2α表达与肺间隔细胞凋亡的关系.方法 采用被动吸烟80 d来复制大鼠COPD模型,采用TUNEL法检测肺组织细胞凋亡、Weslern blot法检测肺组织中活化的半胱天冬酶类3(Caspase-3)、免疫组织化学及Western blot法检测胞核中AP-2α蛋白的表达.结果 采用熏烟法成功复制了大鼠COPD模型.与对照组相比,COPD组大鼠肺组织中活化的Caspase-3增加,肺间隔细胞凋亡增多;肺组织中AP-2α的阳性率增加,胞核中AP-2α蛋白水平增加(P＜0.05).结论 AP-2α可能参与了烟雾暴露所致的大鼠肺间隔细胞凋亡及COPD的发生.     

Apoptotic mechanisms in the pathogenesis of COPD

COPD is a leading cause of morbidity and mortality, characterized by a chronic abnormal inflammatory response to noxious agents. Apoptosis is a physiologic process, critical to cellular homeostasis, in which cell death follows a programmed sequence of events. Apoptosis has been recognized to play an important role in clinical and experimental models of lung diseases. Abnormal apoptotic events in smokers’ and in emphysematous lungs have been shown in epithelial and endothelial lung cells, neutrophils, lymphocytes, and myocytes. Many factors associated with COPD, including cigarette smoke, have the potential to cause apoptosis of alveolar epithelial cells, the main sites of vascular endothelial growth factor (VEGF) production. The decreased expression of VEGF, a known survival factor for endothelial cells, and its receptor, results in lung septal endothelial cell death, leading perhaps to the emphysema observed in COPD. In smokers who develop COPD there is an activation of adaptive immunity, with an infiltration of CD4+ and, especially, CD8 + cells. CD8 + cells are cytotoxic to epithelial cells through the release of granzymes and perforin, which can further induce apoptosis of alveolar cells. Moreover, any reduction in neutrophil apoptosis or dysregulation of macrophage uptake of apoptotic neutrophils could lead to chronic inflammation and tissue injury. Increased rates of T-cell apoptosis may lead to a defective immune response to infective organisms, contributing to the high frequency of infections seen in COPD. Increased apoptosis of skeletal muscle could be responsible for the skeletal muscle atrophy, the main cause of unexplained weight loss in patients with COPD. This paper is a review of the current knowledge on the apoptotic pathways involved in COPD pathogenesis and their interaction with other known contributing factors.     

The destructive index and early lung destruction in smokers

The destructive index (DI), a measure of alveolar septal damage and emphysema, has been proposed as a sensitive index of lung destruction that closely reflects functional abnormalities, especially loss of elastic recoil. To better understand the progression of lung destruction in smokers, we studied the contribution of its principal components: breaks in the alveolar septa (DIb) and the presence of emphysematous spaces (DIe), and compared them to the mean linear intercept (Lm) and DI as originally described. To do this we employed lungs obtained at autopsy from non-smokers and smokers. Lungs were selected by emphysema score (ES) so that all cases were emphysema free (nonsmokers and seven smokers) or had minimal emphysema (nine smokers; ES = 5). Of these indices, only DIb was significantly increased in the lungs of smokers: 17.8 +/- 1.2 versus 12.4 +/- 1.6, p less than 0.05. We also investigated the regional distribution of destruction by comparing results in upper and lower lobes. DIe, but not DIb, was significantly increased in upper lobes of smokers. These data support the notion that increases in DI in the lungs of smokers that occur before increases in Lm or ES reflect the presence of alveolar septal breaks and highlight the importance of alveolar septal destruction as a precursor to the development of airspace enlargement in the lungs of cigarette smokers.     

Role of angiogenesis and vascular remodeling in chronic obstructive pulmonary disease

Recently, angiogenesis and pulmonary vascular remodeling in COPD has been investigated. It has been hypothesized that endothelial dysfunction might be an initiating event that promotes vessel remodeling in COPD.Inflammatory tissue- a pivotal pathological feature of COPD- often hypoxic, can induce angiogenesis through upregulation of factors such as VEGF or FGF and regulators of angiogenesis such as chemokines (CXC family), acting either as angiogenic or angiostatic. Angiopoietins are distinct molecules that act in association with VEGF at different stages of angiogenic process. The regulation of angiogenesis is determined by a dual, yet opposing balance of angiogenic and angiostatic factors that promote or inhibit neovascularization, respectively, not yet elucidated in detail in COPD.Recent studies suggested an increased expression of VEGF in pulmonary muscular arteries of patients with moderate COPD and also in smokers with normal lung function. This was also associated with enlargement of the arterial wall. However, in patients with severe emphysema, the expression of VEGF tended to be low, despite intense vascular remodelling. Furthermore, it has been suggested that VEGF might be involved in the pathogenesis of emphysema through apoptotic mechanisms. Experimental studies showed that the lung microvascular endothelial cells (including the alveolar septal capillary cells) are particularly vulnerable and dependent on VEGF for their survival. Apoptosis of endothelial, leading to the loss of capillaries may well be a central mechanism in patients with emphysema and muscle wasting.This review article summarizes the current knowledge regarding the contribution of vascular remodeling, as well as the pathogenetic and therapeutic implications of pivotal angiogenic mediators, in COPD.     

辛伐他汀对烟雾暴露大鼠肺泡上皮细胞的作用

目的 探讨辛伐他汀对烟雾暴露大鼠肺气肿肺泡上皮细胞及血管内皮生长因子(VEGF)表达的影响.方法 24只12周龄健康雌雄各半Wistar大鼠随机数字表法分为对照组、烟雾组、药物组和烟雾+药物组(烟+药组),每组6只,同步饲养16周,雌雄大鼠同步、分箱饲养16周.分别采用逆转录PCR法测定肺组织中VEGF的mRNA表达,酶联免疫吸附法测定BALF和组织中VEGF含量,免疫组织化学二步法检测VEGF和增殖细胞核抗原(PCNA)表达水平.多组间比较采用单因素方差分析,两两比较采用LSD-t检验.结果 烟+药组大鼠肺泡上皮细胞PCNA阳性细胞构成比[(10.3±2.0)%]明显高于烟雾组[(4.8±0.8)%];BALF和组织匀浆中VEGF水平[(187±15)ng/L和(6782±50)ng/L]接近于对照组[(200±20)ng/L和(7558±330)ng/L],明显高于烟雾组[(71±16)ng/L和(4149±110)ng/L];肺泡和支气管上皮细胞中VEGF表达[(67.7±5.0)%和(49.0±3.0)%]近似于对照组[(68.3±3.3)%和(51.3±2.9)%],明显高于烟雾组[(27.0±5.9)%和(16.3±2.7)%].烟+药组与烟雾组比较,差异均有统计学意义(t值为1.117～12.001,均P＜0.01).结论 辛伐他汀可部分促进肺泡上皮细胞增殖,提高肺组织中VEGF含量及肺泡上皮细胞表达,延缓烟雾暴露所致大鼠肺气肿的进展.     

Correlation of C-reactive protein with disease severity in CT diagnosed emphysema

Background and objective:   Recent studies suggest that CRP levels are related to airflow obstruction. However, limited data exist on the relevance of CRP levels in individuals with or without emphysema. The aim of this study was to assess the relationship between the extent of emphysema, COPD severity and serum CRP levels.
Methods:   Lung function tests and high-sensitivity CRP were examined in 651 males with stable disease who underwent CT screening for lung cancer. CRP levels were examined cross-sectionally in individuals with various degrees of emphysema and in those without emphysema.
Results:   Emphysema was detected in 179 (34.7%) of 516 current smokers. Airflow obstruction was observed in 47 (28.8%) of 163 smokers with mild emphysema, in eight (57.1%) of 14 smokers with moderate emphysema, and in two of two individuals with severe emphysema. CRP levels were not higher in individuals with mild or moderate emphysema compared with individuals without emphysema. Among 98 individuals with airflow obstruction (19.0% of the 516 current smokers), there was a modest correlation between CRP levels and FEV₁%.
Conclusions:   The severity of COPD varied in individuals with similar degrees of emphysema. CRP levels were not significantly higher in individuals with mild or moderate emphysema compared with individuals without emphysema but CRP levels were modestly correlated with FEV₁% among individuals with airflow obstruction.     

El factor de crecimiento queratinocítico humano recombinante induce la progresión de la supervivencia celular mediada por Akt en ratones enfisematosos

IntroductionEmphysema has been associated with decreased VEGF and VEGFR-2 expression and the presence of high numbers of apoptotic alveolar cells. Keratinocyte growth factor stimulates VEGF synthesis which in turn confers normal lung structure maintenance via the Akt pathway. In this study the potential role of rHuKGF in the improvement of deregulated Akt mediated cell survival pathway in emphysematous mice was investigated.MethodsThree experimental groups, i.e., emphysema, treatment and control groups, were prepared. Lungs of mice were treated on 3 occasions by oropharyngeal instillation of 10 mg rHuKGF per kg body weight after induction of emphysema with porcine pancreatic elastase. Subsequently, lung tissues from mice were collected for histopathology and molecular biology studies.Results and discussionHistopathology photomicrographs and destructive index analysis have shown that elastase-induced airspace enlargement and loss of alveoli recovered in the treatment group. rHuKGF stimulates VEGF production which in turn induces the Akt mediated cell survival pathway in emphysematous lungs. mRNA expression of VEGF, VEGFR, PI3K and Akt was significantly increased while Pten, Caspase-9 and Bad was notably decreased in treatment group when compared with emphysema group, being comparable with the control group. Moreover, VEGF protein expression was in accordance with that found for mRNA.ConclusionTherapeutic rHuKGF supplementation improves the deregulated Akt pathway in emphysema, resulting in alveolar cell survival through activation of the endogenous VEGF-dependent cell survival pathway. Hence rHuKGF may prove to be a potential drug in the treatment of emphysema.     

A novel antiapoptotic role for alpha1-antitrypsin in the prevention of pulmonary emphysema

RATIONALE: There is growing evidence that alveolar cell apoptosis plays an important role in emphysema pathogenesis, a chronic inflammatory lung disease characterized by alveolar destruction. The association of alpha1-antitrypsin deficiency with the development of emphysema has supported the concept that protease/antiprotease imbalance mediates cigarette smoke-induced emphysema. OBJECTIVES: We propose that, in addition to its antielastolytic effects, alpha1-antitrypsin may have broader biological effects in the lung, preventing emphysema through inhibition of alveolar cells apoptosis. METHODS, MEASUREMENTS, AND MAIN RESULTS: Transduction of human alpha1-antitrypsin via replication-deficient adeno-associated virus attenuated airspace enlargement and emphysema caused by inhibition of vascular endothelial growth factor (VEGF) receptors with SU5416 in mice, a model of apoptosis-dependent emphysema lacking neutrophilic inflammation. The overexpressed human serine protease inhibitor accumulated in lung cells and suppressed caspase-3 activation and oxidative stress in lungs treated with the VEGF blocker or with VEGF receptor-1 and -2 antibodies. Similar results were obtained in SU5416-treated rats given human alpha1-antitrypsin intravenously. CONCLUSIONS: Our findings suggest that inhibition of structural alveolar cell apoptosis by alpha1-antitrypsin represents a novel protective mechanism of the serpin against emphysema. Further elucidation of this mechanism may extend the therapeutic options for emphysema caused by reduced level or loss of function of alpha1-antitrypsin.     

Bronchoalveolar lavage in COPD: fluid recovery correlates with the degree of emphysema.

Bronchoscopy with bronchoalveolar lavage (BAL) is an important research tool for assessing airway inflammation in a variety of inflammatory lung diseases. In chronic obstructive pulmonary disease (COPD), BAL recovery is often low, making analysis of the recovered fluid difficult to interpret. The present authors hypothesised that the degree of emphysema may predict BAL recovery. A total of 20 COPD patients (mean age 57 yrs, range 49-69) with a median (interquartile range) forced expiratory volume in one second (FEV1) of 51 (33-69)% predicted underwent BAL. Matched "healthy" smokers and nonsmokers served as controls. Emphysema index in COPD patients was calculated on computed tomography scan as the percentage of the right lung with pixels <-950 Hounsfield units. The carbon monoxide diffusing capacity of the lung (DL,CO) was determined by the single-breath method. COPD patients had lower BAL recovery than controls. COPD patients with an emphysema index <1 had higher BAL recovery than patients with an emphysema index >1. BAL recovery correlated negatively to emphysema index and positively to DL,CO. However, no correlation was found between recovery and FEV1. In conclusion, the extent of emphysema evaluated by computed tomography-scan index and carbon monoxide diffusing capacity of the lung may predict a low bronchoalveolar lavage recovery in chronic obstructive pulmonary disease patients. These parameters may, therefore, be useful when chronic obstructive pulmonary disease patients are selected for bronchoscopy with bronchoalveloar lavage. The present study underlines the importance of careful phenotyping of chronic obstructive pulmonary disease patients.     

Sirtuin 1 Activator SRT1720 Protects Against Lung Injury via Reduction of Type II Alveolar Epithelial Cells Apoptosis in Emphysema

In chronic obstructive pulmonary disease (COPD), two major pathological changes that occur are the loss of alveolar structure and airspace enlargement. Type II alveolar epithelial cells (AECII) play a vital role in maintaining alveolar homeostasis and lung tissue repair. Sirtuin 1 (SIRT1), a NAD⁺-dependent histone deacetylase, regulates many pathophysiological processes including inflammation, apoptosis, cellular senescence and stress resistance. The main aim of this study was to investigate whether SRT1720, a pharmacological SIRT1 activator, could protect against AECII apoptosis in rats with emphysema caused by cigarette smoke exposure and intratracheal lipopolysaccharide instillation in vivo. During the induction of emphysema in rats, administration of SRT1720 improved lung function including airway resistance and pulmonary dynamic compliance. SRT1720 treatment up-regulated the levels of surfactant protein (SP)A, SPC, SIRT1 and forkhead box O 3, increased SIRT1 activity, down-regulated the level of p53 and inhibited AECII apoptosis. Lung injury caused by emphysema was alleviated after SRT1720 treatment. SRT1720 could protect against AECII apoptosis in rats with emphysema and thus could be used in COPD treatment.     

内皮素-1受体拮抗剂对肺气肿大鼠肺组织的保护作用及机制

目的 探讨内皮素-1受体拮抗剂对肺气肿大鼠肺组织的保护作用及机制.方法 将24只SD大鼠随机分为健康对照组、肺气肿模型组、BQ123干预组、Bosentan干预组,每组6只.测4组大鼠平均内衬间隔(MLI)和肺泡破坏指数(DI).用缺口末端标记法(TUNEL)测肺泡间隔细胞凋亡;用免疫组化法、Western blot测caspase-3表达;用明胶酶谱法测基质金属蛋白酶(MMP)-2、MMP-9活性;用ELISA测TNFα、IL-1β浓度.结果 (1)肺气肿模型组大鼠出现典型肺气肿变化,MLI[(108.7±6.8)μm]和DI[(62.2±7.0)%]较健康对照组显著增高[(69.8±6.6)μm;(13.9±2.7)%;P<0.01];BQ123干预组[MLI(89.0±7.4)μm,DI(41.5±4.5)%]、Bosentan干预组[MLI(81.9±6.1)μm,DI(44.0±8.5)%]均较肺气肿模型组显著降低,但2组间差异无统计学意义.(2)4组大鼠肺内均可见凋亡细胞,肺气肿模型组凋亡指数(AI)较健康对照组明显增高,BQ123干预组、Bnsentan干预组AJ较肺气肿模型组明显减低,但仍高于健康对照组(P<0.01).(3)肺气肿模型组大鼠肺组织caspnse-3表达明显增高,BQ123干预组、Bosentan干预组caspase-3表达较肺气肿模型组明显降低.(4)肺气肿模型组大鼠肺内MMP-2、MMP-9活性较健康对照组明显增高,BQ123干预组、Bosentan干预组MMP-2、MMP-9活性降低,但差异无统计学意义.(5)肺气肿模型组大鼠肺组织匀浆上清中TNFα、IL-1β水平较健康对照组明显增高,BQ123干预组、Bosentan干预组TNFα、IL-1β水平较肺气肿模型组明显减低.结论 内皮素受体拮抗剂可通过抑制肺气肿大鼠凋亡基因表达,降低MMPs活性和减少炎性因子释放而起到部分保护作用.     

State of the art. Mechanistic heterogeneity in chronic obstructive pulmonary disease: insights from transgenic mice

Alveolar destruction is a cardinal feature of emphysema but is not traditionally believed to contribute to the pathogenesis of "classical" asthma. However, the relationship between chronic obstructive pulmonary disease (COPD) and asthma is controversial and the variety of mechanisms that can mediate the alveolar destruction in emphysema have not been adequately defined. To address these issues, we used overexpression transgenic approaches to define the effects of Th1/Tc1 and Th2/Tc2 cytokines in the mature murine lung and compared findings in these transgenic systems to the effects of similar interventions after cigarette smoke (CS) exposure. In these experiments, the Th1/Tc1 and Th2/Tc2 cytokines IFN-gamma and interleukin (IL)-13, respectively, both caused emphysema. The IFN-gamma response was associated with neutrophilia but was not associated with mucus metaplasia or a major fibrotic response. In this setting, IFN-gamma was a potent stimulator of matrix metalloproteinases (MMPs), cathepsins, and CXC and other chemokines while inhibiting secretory leukocyte proteinase inhibitor (SLPI). Interestingly, IFN-gamma induced its destructive effects via at least two mechanisms, a CCR5/cathepsin-dependent and apoptosis-mediated pathway and an MMP-12-dependent/apoptosis-independent pathway. CS-induced inflammation, apoptosis, and emphysema were also induced by IFN-gamma- and CCR5-dependent mechanisms. In contrast, IL-13-induced emphysema was associated with eosinophilia, mucus metaplasia, and pulmonary fibrosis. In this setting, IL-13 stimulated MMPs, cathepsins, and a variety of CC chemokines while inhibiting alpha(1)-antitrypsin. A cathepsin-dependent apoptosis pathway also contributed to this remodeling response. Interestingly, abnormalities in vascular endothelial growth factor (VEGF) were also appreciated with VEGF(165) excess producing an asthmalike pulmonary response and IFN-gamma abrogating this response while inducing emphysematous alveolar destruction. These findings provide molecular support for both points of view in the British/Dutch hypothesis controversy regarding the relationship between asthma and COPD. They also highlight the complexity of the pathways that can induce alveolar destruction and suggest that there is a continuum, based on VEGF, between asthma and COPD.