Clara cell protein as a marker of Clara cell damage and bronchoalveolar blood barrier permeability.

The 16 kDa Clara cell protein (CC16), an abundant component of airway secretions, has recently been proposed in humans as a pulmonary marker measurable not only in bronchoalveolar lavage fluid (BALF) but also in serum. The aim of the present study was to investigate the changes and determinants of CC16 concentrations in these fluids in normal rats and rats with lung injury. Female Sprague-Dawley rats were given a single i.p. injection of arachis oil (n=20) or chemicals in arachis oil (n=10) that mainly damage Clara cells (4-ipomeanol (IPO) 8 mg x kg(-1) and methylcyclopentadienyl manganese tricarbonyl (MMT) 5 mg x kg(-1)) or endothelial cells (alpha-naphthylthiourea (ANTU) 5 mg x kg(-1)). CC16 concentration (mean+/-sD in microg x L(-1)), measured by a sensitive latex immunoassay, was significantly reduced in BALF of all treated groups (IPO 380+/-100; MMT 730+/-200; ANTU 1,070+/-200; controls 1,700+/-470). The same pattern of decrease was observed in the labelling of Clara cells with an anti-CC16 antiserum as well as in the CC16 messenger ribonucleic acid levels assessed by Northern enzyme-linked immunosorbent assay. In serum, by contrast, CC16 was significantly increased in all treated groups (IPO 31+/-7; MMT 22+/-12; ANTU 52+/-24; controls 15+/-6). This rise of CC16 in serum was associated with an elevation of albumin in BALF which is an index of increased bronchoalveolar/blood barrier permeability. In conclusion, lung injury induces a decrease of the 16 kDa Clara cell protein in bronchoalveolar lavage fluid owing to a reduced production by damaged Clara cells, and an increase in serum protein levels resulting from its enhanced leakage across the bronchoalveolar/blood barrier. This study provides new insights into the understanding of the changes of lung secretory proteins in bronchoalveolar lavage fluid and serum.     

The effect of N-acetylcysteine on Clara cells and Clara cell 16 kDa protein in a murine model of allergen-induced airway inflammation

OBJECTIVE: The aim of this study was to investigate the number of Clara cells and the production and secretion of Clara cell 16 kDa protein (CC16) in a murine model of allergen-induced airway inflammation, as well as the effects of N-acetylcysteine (NAC) on CC16 and Clara cell numbers, in order to determine the mechanism of the anti-inflammatory effect of NAC. METHODOLOGY: BALB/c mice were divided into control, ovalbumin (OVA) and NAC groups. An allergen-induced airway inflammation model (OVA group) was established by sensitizing and challenging mice with OVA. NAC was administered as an oral treatment. The number of Clara cells and the production of CC16 were determined by immunohistochemistry. The CC16 levels in bronchoalveolar lavage fluid (BALF) were determined by Western blotting. RESULTS: The proportion of Clara cells in terminal and respiratory bronchioles significantly decreased in the OVA group compared to the control group (P < 0.01). NAC treatment did not change the proportion of Clara cells in the OVA group (P > 0.05). CC16 production by Clara cells in the OVA groups was significantly lower than that of the control group (P < 0.01), but was elevated following NAC treatment (P < 0.05). The CC16 level in BALF of the OVA group was lower than that of the control group (P < 0.01), but was elevated by NAC treatment (P < 0.05). NAC reduced the total number of white cells and the percentage of eosinophils in BALF. Moreover, it inhibited airway inflammation. CONCLUSIONS: The number of Clara cells and the production and secretion of CC16 were reduced in a murine model of allergen-induced airway inflammation. Antioxidants can enhance the expression of CC16, which might be a mechanism by which they suppress airway inflammation.     

CC16蛋白质与肺部疾病

CC16蛋白质是由细支气管、终末细支气管黏膜上的无纤毛柱状上皮细胞——clara细胞分泌产生。CC16为组织特异性蛋白,主要表达在肺组织,它是一种肺的内源性抗炎因子。其抗炎作用可能非常复杂,机制之一是抑制磷脂酶A2的活性。由于其在肺部高表达,CC16与许多肺部疾病的发生发展有关,例如支气管哮喘、COPD、间质性肺疾病、肺癌、ALI等。     

丹参酮ⅡA 对急性肺损伤小鼠气道炎症抑制作用研究

目的：研究丹参酮ⅡA (TⅡA)对 ALI 小鼠气道炎症的抑制作用。方法用脂多糖(LPS)刺激 C57小鼠,建立 ALI 的动物模型,同时用 TⅡA 进行干预,实验共分为四组：正常对照组、LPS 组、TⅡA 组和 TⅡA+LPS 组,HE 染色观察各组小鼠 BALF 中炎性细胞的分布变化并对细胞进行分类计数,聚合酶链反应(PCR)及酶联免疫吸附测定(ELISA)等方法观检测 TⅡA 对 ALI小鼠肺组织及 BALF 中 Muc5AC、肿瘤坏死因子α(TNF-α)表达水平的影响;结果正常对照小鼠BALF 中淋巴细胞占绝大多数,单独给予 T Ⅱ A 对 BALF 细胞分布无影响,LPS 所致的 ALI 小鼠BALF 中炎性细胞总数明显增加,且以中性粒细胞占多数,TⅡA 能够明显抑制 ALI 小鼠 BALF 中炎性细胞总数及中性粒细胞数;TⅡA 能够明显抑制 ALI 小鼠 BALF 中气道黏蛋白 Muc5AC 及 TNF-α的表达水平。结论 TⅡA 能够明显抑制 ALI 小鼠气道炎症水平。     

糖皮质激素对哮喘大鼠Clara细胞分泌蛋白表达的影响

目的　观察吸入糖皮质激素对大鼠支气管哮喘 (简称哮喘 )模型肺组织Clara细胞分泌蛋白 (CCSP)mRNA表达的影响。方法　用卵白蛋白 (OVA)致敏、雾化建立大鼠哮喘模型 ,以逆转录 聚合酶链反应 (RT PCR)、斑点免疫印迹法 ,分别检测大鼠激发哮喘 3天后肺组织CCSPmRNA表达水平、支气管肺泡灌洗液 (BALF)CCSP蛋白浓度及雾化吸入布地奈德的影响。结果　哮喘组大鼠肺组织CCSPmRNA表达量为 0 .5 6± 0 .0 5 ,与正常对照组 (0 .6 5± 0 .0 4 )比较差异有显著性 (P <0 .0 1) ;激素治疗组CCSPmRNA表达量为 0 .6 3± 0 .0 4 ,与哮喘组 (0 .5 6± 0 .0 5 )比较差异也有显著性 (P <0 .0 5 )。哮喘组大鼠BALF中CCSP蛋白含量为 4 9± 5 ,与正常对照组 (6 0± 5 )比较 ,差异有显著性 (P <0 .0 1) ;激素治疗组CCSP蛋白含量 (5 7± 5 )与哮喘组比较 (P <0 .0 5 ) ,BALF中嗜酸细胞比例降低 ,气道炎症反应减轻。结论　CCSPmRNA表达减少导致CCSP水平下降 ,从而促进气道炎症而参与哮喘发病。雾化吸入糖皮质激素可增加CCSPmRNA表达 ,抑制哮喘气道炎症。     

Serum Clara cell protein (CC16), a marker of the integrity of the air-blood barrier in sarcoidosis.

To test the hypothesis that sarcoidosis is associated with an intravascular leakage of lung epithelium secretory proteins, the occurrence and determinants in serum of sarcoid patients of CC16, a small size and readily diffusible lung-specific protein of 16 kDa secreted by bronchiolar Clara cells, was investigated. CC16 was measured by a sensitive latex immunoassay in the serum of 117 patients with established sarcoidosis and of 117 healthy subjects matched for age, sex and smoking status. Stepwise regression analysis was used to identify extrapulmonary variables of CC16 changes in serum. These changes were then compared with biochemical and cellular parameters in bronchoalveolar lavage fluid (BALF) as well as with the number of CC16 immunostaining cells on bronchial or pulmonary biopsy samples. CC16 concentration in serum of sarcoid patients was significantly increased, compared to their matched controls (25.9 +/- 16.2 versus 13.9 +/- 5.2 microg x L(-1)). In nonsmoking patients without significant renal impairment, CC16 in serum increased with the severity of the chest radiograph and computed tomography changes, and was on average 50-100% higher when parenchymal involvement was present. Sarcoid patients had, however, normal levels of CC16 in BALF and an unchanged number of CC16-immunopositive cells in lung biopsy samples, suggesting that an increased secretion of CC16 in the sarcoid lung is very unlikely, and that the elevation of CC16 in sarcoidosis results from an increased intravascular leakage of the protein across the air-blood barrier. The present study suggests that CC16 in serum might provide a useful tool to noninvasively evaluate the damage and increased permeability to proteins of the air-blood barrier associated with sarcoidosis.     

Clara cell protein as a biomarker for ozone-induced lung injury in humans.

Exposure to ozone (O3) impairs lung function, induces airway inflammation and alters epithelial permeability. Whilst impaired lung function and neutrophilia have been observed at relatively low concentrations, altered lung epithelial permeability is only seen after high-dose challenges. The appearance of Clara cell protein (CC16) in serum has been proposed as a sensitive marker of lung epithelial injury. Here, the use of CC16 as an injury biomarker was evaluated under a controlled exposure to O3 and the relationship between this marker of lung injury and early lung function decrements was investigated. Subjects (n=22) were exposed on two separate occasions to 0.2 parts per million O3 and filtered air for 2 h. Blood samples were drawn and lung function assessed at 2 h pre-exposure, immediately before and immediately after exposure as well as 2 and 4 h postexposure. O3 increased CC16 serum concentrations at 2 h (12.0+/-4.5 versus 8.4+/-3.1 microg x L(-1)) and 4 h postexposure (11.7+/-5.0 versus 7.9+/-2.6 microg x L(-1)) compared with air concentrations. Archived samples from O3 studies utilising the same design indicated that this increase was sustained for up to 6 h postexposure (9.1+/-2.6 versus 7.1+/-1.7 microg x L(-1)) with concentrations returning to baseline by 18 h (7.7+/-2.9 versus 6.6+/-1.7 microg x L(-1)). In these studies, the increased plasma CC16 concentration was noted in the absence of increases in traditional markers of epithelial permeability. No association was observed between increased CC16 concentrations and lung function changes. To conclude, Clara cell protein represents a sensitive and noninvasive biomarker for ozone-induced lung epithelial damage that may have important uses in assessing the health effects of air pollutants in future epidemiological and field studies.     

Effects of theophylline on chronic inflammatory lung injury induced by LPS exposure in guinea pigs.

BACKGROUND: Pathogenesis of COPD is, at least in part, attributable to the chronic accumulation of neutrophils in the airways, and morphological changes such as hyperplasia of goblet cells in the airways are often observed in this disease. These structural changes were induced in guinea pigs by repetitive inhalations of LPS, and the effects of theophylline and dexamethasone were examined. METHODS: Male Hartley Guinea pigs weighing about 300 g were exposed to a nebulized solution of LPS (30 microg/mL) for 1 hour. Exposure to LPS was performed 15 times at 48-hour intervals. Histological analysis was performed, and infiltration of leukocytes in BALF, airway hyperreactivity and hydroxyproline content of the lung were measured 24 or 48 hours after the final exposure of LPS. Drugs were administered every day until 30 minutes before the final exposure. RESULTS: Repetitive exposure to LPS induced an influx of inflammatory cells into the BALF. Histological changes such as accumulation of inflammatory cells in the lung parenchyma, enlargement of alveoli, swelling of the alveolar walls and goblet cell hyperplasia in the airways were observed. Airway hyperreactivity and increased lung hydroxyproline content were also found in this model of chronic inflammatory lung injury. Some of these changes induced by repetitive LPS exposure were improved by treatment with theophylline or dexamethasone. CONCLUSIONS: Theophylline improved airway injury as well as airway hyperreactivity induced by repetitive exposure of the guinea pigs to LPS. These results suggest that theophylline treatment has ameliorative effects on airway disease with chronic inflammation.     

Uteroglobin-related protein 1 and clara cell protein in induced sputum of patients with asthma and rhinitis

Rationale: Uteroglobin-related protein 1 (UGRP1) and Clara cell protein (CC16), members of the secretoglobin family, increasingly appear to play a role in airway inflammatory response. OBJECTIVE: To explore levels of UGRP1 and CC16 in induced sputum of patients with asthma and rhinitis. METHODS: Induced-sputum samples of patients with asthma or rhinitis (n = 32 each; atopic asthma, n = 24; atopic rhinitis, n = 20) and from 19 nonsmoking nonatopic control subjects were analyzed for cytology and levels of UGRP1, CC16, and albumin. Measurements and main results: Sputum UGRP1 increased in both asthma and rhinitis, most strikingly so in asthma, in which changes were most significant in atopic individuals. By contrast, sputum CC16 did not change significantly in either condition, although it was positively correlated with UGRP1 in patients and control subjects. Changes in sputum UGRP1 in atopic asthma were not linked to permeability changes reflected by increased albumin levels but correlated positively with sputum macrophages and negatively with eosinophils. The observed differences in UGRP1 and CC16 may be linked to different cell populations being responsible for their secretion; UGRP1 is mainly secreted in larger conducting airways, whereas CC16 is mainly secreted by the nasal and peripheral airways epithelium. CONCLUSIONS: The increase in UGRP1 but not of CC16 in asthma and rhinitis suggests that UGRP1 may play a role in these inflammatory diseases.     

Clara cell protein-positive epithelial cells are reduced in small airways of asthmatics.

Clara cell 10 kilodalton protein (CC10), the predominant product from nonciliated cells in the epithelial lining of bronchioles (Clara cells), has been shown to have immunomodulatory and anti-inflammatory activity, and may play roles in controlling inflammation in the airway. This study was designed to examine immunohistochemical expression of CC10 in epithelial cells in small airways (perimeter < 6 mm) of asthmatic and control nonsmokers who underwent lung resection because of peripheral lung carcinoma and to compare CC10-positive epithelial cell proportions with numbers of inflammatory cells in small airways of asthmatics. Significantly decreased proportions of CC10-positive epithelial cells and significantly increased numbers of T cells, activated eosinophils, and mast cells in small airways of asthmatics were found compared with those of control subjects. CC10-positive epithelial cell proportions inversely correlated with numbers of T cells and mast cells in small airways of asthmatics. Decreases of CC10-producing cells may give an accelerating cause for further aggravation of inflammatory responses in chronic asthma.     

Clara细胞分泌蛋白CC16与支气管哮喘的关系

CC16(Clara细胞分泌蛋白-16)是Clara细胞主要的分泌物,具有抗炎、抗氧化、调节免疫及抑制肿瘤的生成和转移等多种生物活性。我国近年来研究显示CC16与支气管哮喘的发病机制、诊断及治疗有密切关系,其中CC16与Th1/Th2失衡的关系成为一研究热点。现就CC16与支气管哮喘的关系作一综述,为以后进一步深入研究作铺垫。     

Keratinocyte growth factor improves alterations of lung permeability and bronchial epithelium in allergic rats.

Chronic allergic asthma is associated with marked inflammatory reaction, microvascular leakage and epithelium injury. As previously shown in a rat model of chronic asthma, these alterations increase lung permeability and distal airway fluid clearance. Keratinocyte growth factor (KGF) has been shown to induce epithelial cell proliferation and to protect from acute lung injuries. Therefore, the current authors evaluated the potential role of KGF treatment on lung permeability and airway inflammation in rats with chronic asthma. KGF (1 mg x kg(-1)) was administered intravenously before the last ovalbumin (OVA) challenge in sensitised rats. Permeability was assessed by the leak of radiolabelled albumin from the alveolar and systemic compartments. Histopathological analysis was also performed. Treatment with KGF decreased the leak of both markers and decreased the level of extravascular lung water in sensitised rats challenged with OVA. KGF treatment also reduced the inflammatory cell number in bronchoalveolar lavage fluid but not in bronchial mucosa. KGF markedly limited the allergen-induced alterations in epithelium integrity and the expression of the intercellular junction proteins beta-catenin and zonula occludens protein-1. In conclusion, keratinocyte growth factor administration markedly limits lung permeability and airway inflammation, an effect associated with a decrease in epithelium alterations during chronic allergic asthma. These data open new prospects in the therapeutic strategy of asthma.     

烟草雾吸入导致慢阻肺机制的实验研究——大鼠Clara细胞结构及其分泌蛋白的变化

为探讨烟草雾吸入诱导的慢性阻塞性肺疾病 (COPD)大鼠气道Clara细胞及其分泌蛋白 (又称Clara细胞 10kDa蛋白 ,CC10 )表达的变化 ,采用自制的染毒箱 ,使大鼠吸入烟草雾制作COPD模型 ,对Clara细胞进行电镜及免疫组化观察 ,并测定大鼠气道阻力及呼吸系统总顺应性。COPD大鼠终末及呼吸性细支气管Clara细胞数量减少 ,胞浆内滑面内质网扩张 ;终末及呼吸性细支气管上皮细胞CC10表达减少 ;呼吸功能检查显示气道阻力增加、呼吸系统总顺应性下降 ;气道上皮细胞CC10阳性细胞百分率与气道阻力呈负相关。COPD大鼠终末及呼吸性细支气管上皮细胞Clara细胞数量减少 ,气道上皮细胞CC10表达减少 ,CC10阳性细胞百分率与气道阻力呈负相关、与动态顺应性呈正相关。这可能与大鼠气道阻力增加及呼吸系统总顺应性下降有关     

烟草雾吸入导致慢阻肺机制的实验研究：大鼠Clara细胞结构 …

为探讨烟草雾吸入诱导的慢性阻塞性肺疾病（ＣＯＰＤ）大鼠气道Ｃｌａｒａ细胞及其分泌蛋白（又称Ｃｌａｒａ细胞１０ｋＤａ蛋白，ＣＣ１０）表达的变化，采用自制的染毒箱，使大鼠吸入烟草雾制作ＣＯＰＤ模型，对Ｃｌａｒａ细胞进行电镜及免疫组化观察，并测定大鼠气道阻力及呼吸系统总顺应性。ＣＯＰＤ大鼠终末及呼吸性细支气管Ｃｌａｒａ细胞数量减少，胞浆内滑面内质网扩张；终末及呼吸性细支气管上皮细胞ＣＣ１０表达减少；呼吸     

吸烟者Clara细胞形态和功能的改变

目的 :观察吸烟者小气道中Clara细胞形态和功能的改变 ,了解Clara细胞在吸烟所致肺部损伤中的作用。方法 :收集手术肺组织标本 5 4例 ,免疫组织化学法观察小气道中Clara细胞分布及所占比例 ,RNA酶保护实验测定肺组织中Clara细胞 16kD特异性分泌蛋白 (CC16 )mRNA表达并用Western法测定CC16蛋白水平。结果 :终末及呼吸性细支气管中 ,Clara细胞占上皮细胞的比例在吸烟组较非吸烟组减低 (终末细支气管 11 7%、18 8% ;呼吸性细支气管 15 2 7%、2 5 32 % ,P <0 0 1)。戒烟组较吸烟组回升 (分别为 19 4 1%、13 2 % ,P <0 0 5 )。吸烟组杯状细胞增生明显 ,P <0 0 1。呼吸性细支气管中 ,戒烟组杯状细胞增生明显减轻 ,P <0 0 1。吸烟组肺组织中CC16mRNA表达 (0 2 9± 0 0 2、0 5 1± 0 0 6 ,P <0 0 1)及蛋白水平 (0 87± 0 12、1 78± 0 31,P <0 0 1)均下降 ,戒烟组有所恢复 ,但无显著性差异。结论 :吸烟破坏Clara细胞 ,使其分泌蛋白CC16表达减少 ,戒烟可使Clara细胞的破坏部分恢复。Clara细胞数目减少与功能的变化削弱人体保护机制 ,导致肺损伤。其改变可能是吸烟所致肺部疾病形成的机制之一。     

LPS-induced lung inflammation is linked to increased epithelial permeability: role of MLCK.

The respiratory system is directly exposed to low levels of lipopolysaccharide (LPS), present as a contaminant on airborne particles. In cystic fibrosis, the prevailing data identify structural changes of the airway epithelium, as well as tight junction dilatation. This study was aimed at determining the contribution of myosin light chain kinase to maintaining airway epithelium barrier integrity in the lung inflammatory response to LPS in rats. The effects of the selective myosin light chain kinase inhibitor, 5-iodonaphthalene-1-sulphonyl-homopiperazine (ML-7), were evaluated: 1) on pulmonary inflammation and airway epithelium barrier permeability alterations induced by intra-tracheal LPS from Pseudomonas aeruginosa; and 2) on levels of the phosphorylated form of the myosin light chain, which is increased in a human airway epithelial cell line (NCI-H292) and tracheal tissue after LPS exposure. The results show that LPS increased airway epithelium barrier paracellular permeability and lung inflammation, and that pre-treatment with ML-7 inhibited both effects. This effect of ML-7 was associated with the inhibition of phosphorylated myosin light chain in both NCI-H292 cells and tracheal tissue. The data, obtained using in vivo and in vitro approaches, demonstrate a key role for myosin light chain kinase in lung inflammation, and suggest that myosin light chain kinase could be a potential target for novel drugs intended for relief of lung injury.     

大鼠哮喘模型Clara细胞及其分泌蛋白的表达

目的　观察大鼠哮喘模型Clara细胞及其分泌蛋白 (CCSP)的表达。方法　SD大鼠 2 4只 ,分为哮喘模型组和健康对照组。哮喘模型组大鼠用卵白蛋白 (OVA)致敏激发建立大鼠哮喘模型。用逆转录 聚合酶链反应、斑点免疫印迹、免疫组化及图像分析方法检测 2组大鼠肺组织CCSPmRNA表达、支气管肺泡灌洗液(BALF)中CCSP蛋白水平、细小支气管Clara细胞比率及气道形态学参数。结果　哮喘模型组大鼠OVA激发2周的支气管总管壁面积、内壁面积及平滑肌面积均较健康对照组和哮喘模型组OVA激发 1周时的增加 (P <0 0 1) ,并与CCSP及其mRNA呈负相关 (r分别为 - 0 5 9、- 0 72、- 0 6 5、- 0 6 3、- 0 78及 - 0 73,P <0 0 1)。哮喘模型组大鼠细支气管、终末细支气管及呼吸性细支气管Clara细胞数量减少 (P <0 0 1或 0 0 5 )。哮喘模型组大鼠肺组织CCSPmRNA表达较健康对照组降低 ,BALF中CCSP蛋白含量降低。结论　CCSPmRNA表达降低 ,Clara细胞数量减少。     

Altered lung function relates to inflammation in an acute LPS mouse model

Preclinical in vivo models of lipopolysaccharide (LPS) -induced acute lung injury are commonly used to recapitulate pathophysiological features of chronic obstructive pulmonary disease and acute exacerbations. The LPS-induced lung inflammation is well described; however, whether the inflammatory response relates temporally to specific alterations in lung function has not been elucidated.We have investigated the effects of acute LPS inhalation in mice up to 96 h post LPS. Quantitation of inflammatory cells and inflammatory mediators in bronchoalveolar lavage fluid and non-invasive and invasive lung function measurements were performed at corresponding time points. The inhibitory effect of the glucocorticoid, budesonide, on LPS-induced lung inflammation and lung function was determined.LPS inhalation induced distinct histopathological changes, and infiltration of inflammatory cells to the lungs peaked at 48 h. At this time point, significantly increased inflammatory mediators and significantly altered lung capacity and mechanics parameters were observed. Budesonide given per os prevented the LPS-induced lung inflammation and lung dysfunction.These results demonstrate a temporal relationship between the peak of inflammatory cell influx and significant impairment of lung function, suggestive of a causative role of inflammation. These results allow better understanding of the functional consequences of lung inflammation in respiratory diseases.     

SIRT1减弱对脂多糖致急性呼吸窘迫综合征小鼠的促炎作用

目的探讨SIRT1对脂多糖(LPS)诱导的急性呼吸窘迫综合征(ARDS)小鼠炎症反应的作用及其机制。方法采用SIRT1基因敲减小鼠SIRT1~(+/-)与野生型小鼠,qRT-PCR,Western Blot检测两种小鼠肺组织中的相关基因表达差异。两种小鼠用LPS腹腔注射法造模,同时设生理盐水对照组,观察肺组织病理形态学变化,测定肺湿干比(W/D比),BCA法测定支气管肺泡灌洗液(BALF)中总蛋白浓度,ELISA法测定BALF及血浆中炎症因子TNF-α、IL-6的含量,Western Blot检测肺组织p-p38MAPK、p38MAPK、p-ATF2的表达变化。结果与野生型小鼠相比,SIRT1~(+/-)肺组织中SIRT1在mRNA表达和蛋白表达均显著降低,差异有统计学意义(P0.01)。LPS致ARDS后,两种小鼠病理形态学观察均表现为肺组织炎症细胞浸润,肺泡结构破坏,间质水肿,肺泡间隔增厚,而SIRT1~(+/-)小鼠肺组织破坏更严重。在SIRT1~(+/-)小鼠中,肺W/D比值,BALF中总蛋白浓度,BALF及血浆中炎症因子肿瘤坏死因子-α(TNF-α)、白细胞介素-6(IL-6)的含量,均明显高于野生型小鼠(P0.05),肺组织p-p38MAPK/p38MAPK、p-ATF2的表达增加也更显著(P0.05)。结论 SIRT1基因在LPS致伤ARDS小鼠的炎症进程中起着非常重要的作用,其机制可能与Sirt1诱导的p38 MAPK-p-ATF2信号通路的活化增强有关。     

A study on tumor necrosis factor alpha, macrophage inflammatory protein-2 and myeloperoxidase in blood, broncho-alveolar fluid and lung tissues of rat chronic bronchitis model

OBJECTIVE: To study the nature and mechanisms of airway inflammation in chronic bronchitis and observe the effects of inhaled glucocorticoids on inflammatory indices. METHODS: Rat chronic bronchitis model was established by intratracheal instillation of small dose of lipopolysaccharide (LPS, 1 g/L). Experiments were performed in 28 male Sprague-Dawley rats, which comprised four groups in random, i.e. chronic bronchitis model group, normal saline treated group, dexamethasone treated group and healthy control group. The levels of myeloperoxidase (MPO) of blood and lung tissues, and tumor necrosis factor (TNF)alpha and macrophage inflammatory protein-2 (MIP-2) of plasma, broncho-alveolar fluid (BALF) and lung tissues were determined by biochemical and ELISA methods. Total and differential white blood cell counts of BALFwere carried out. RESULTS: (1) The levels of TNFalpha and MIP-2 in BALF and lung tissues, and MPO in lung tissues of chronic bronchitis model group were significantly increased than those of control group (P < 0.05). (2) More significant increase in total white blood cell count and neutrophils in BALF was found in rat chronic bronchitis group than in control group (P < 0.001). (3) Significant positive correlations were observed between the level of MPO and MIP-2 of lung tissues, the level of MPO and TNFalpha of lung tissue and the total cell counts and the level of MIP-2 of BALF and lung tissue. (4) More significant decrease in total cell counts and neutrophils of BALF and levels of MPO in lung tissue was found in dexamethasone-treated group as compared to those of chronic bronchitis group. CONCLUSION: Recruitment and activation of neutrophils seem to be the characteristics of chronic bronchitis. TNFalpha and MIP-2 may be involved in the process of chemotaxis and activation in airway inflammation in chronic bronchitis. Inhaled steroids might have some effects on chronic bronchitis by limiting the airway inflammation.