Inflammatory mediators and cellular infiltration of the lungs in a guinea pig model of the late asthmatic reaction

Alterations in cell numbers, vascular permeability, and concentrations of various inflammatory mediators in the lung were measured in a guinea pig model of the late asthmatic reaction. Animals sensitized by inhalation of ovalbumin were challenged with an aerosol of ovalbumin or saline, and bronchoalveolar lavage fluid (BALF) and peripheral blood were collected after periods ranging from 5 min to 72 h. Increased vascular leakage within the lungs was indicated by elevated BALF/plasma albumin ratios at all time points, and was maximal 6 h after challenge. There were increased numbers of eosinophils in BALF by 6 h after challenge and they remained elevated at least until 72 h. A corresponding increase in the proportion of blood leukocytes represented by eosinophils was observed at 6 and 17 h, which suggests that these cells may be drawn to the lung following their release into the circulation, but by 72 h the proportion in blood had returned to normal. A transitory neutrophilia was evident in BALF and blood 6 h after allergen exposure, but there were no allergen-induced changes in BALF numbers of macrophages, lymphocytes, epithelial cells, or mast cells (as assessed by concentrations of cell-associated histamine). beta-Glucuronidase activity was significantly increased in BALF of guinea pigs at 2 h and 17 h following challenge. The degree to which eicosanoids can be recovered in BALF was investigated by instilling a range of tritiated compounds into the lungs of normal guinea pigs at the time of lavage. Ratio high-performance liquid chromatography revealed that there had been little metabolism of the eicosanoids recovered in BALF. However, there was evidence for a rapid removal of these mediators from the lung, a process which will militate against their accurate quantitation in BALF. Histamine, prostaglandin D2, and thromboxane B2 were detected in BALF but did not differ between treatment groups, and levels showed no simple relationship with the other inflammatory changes measured.     

Early and late-phase bronchoconstriction after allergen challenge of nonanesthetized guinea pigs. I. The association of disordered airway physiology to leukocyte infiltration

We describe a guinea pig model of asthma in which animals were sensitized and challenged by inhalation of aerosolized ovalbumin. Challenge was performed under cover of mepyramine (10 mg/kg) to allow a high enough concentration of ovalbumin to elicit consistent late responses. Airway resistance and thoracic gas volume of conscious guinea pigs was assessed by whole body plethysmography before and at regular intervals for as long as 72 h after challenge. At the same time points, cellular changes in the lung were assessed by both examination of cells recovered by bronchoalveolar lavage (BAL) and lung histology. There were no significant changes in specific airway conductance (SGaw), BAL cell content or lung histology in animals challenged with saline control. Challenge with 2% ovalbumin caused an early fall in SGaw, which peaked at 2 h and amounted to a 43.7 +/- 4.1% fall from baseline. This was followed by 2 late responses, the first reaching maximum at 17 h with a 46.9 +/- 4.5% decrease in SGaw from baseline and the second at 72 h with a 39.0 +/- 3.5% fall in SGaw. Examination of BAL fluid revealed a 7-fold increase in neutrophils at 6 h and a 17-fold increase at 17 h, after which numbers decreased to baseline. Eosinophilia developed more slowly, being insignificant at 6 h and 6-fold at 17 h; by 72 h, eosinophils constituted 48.9 +/- 6.9% of the total cells recovered. No changes in mononuclear cells or lymphocytes were observed. Histologic examination of the lung revealed a progressive eosinophil infiltration of the airways, but not alveoli or vascular bed. Electron microscopy showed degranulation of eosinophils recovered by BAL and discharge of mucus from goblet cells in the trachea. Because these changes are similar to those that occur after allergen challenge in human asthma, we suggest that this represents a useful animal model in which to study the mechanism of early and late bronchoconstriction responses.     

CD86对抗原引起气道嗜酸细胞浸润和气道高反应性作用？…

目的 探讨ＣＤ８６分子对抗原引起气道炎症和气道高反应性的影响,加深认识ＣＤ８６在支气管哮喘发病机制中的作用。方法 应用鸡卵清蛋白致敏和刺激ＢＡＬＢ／ｃ小鼠以诱导嗜酸细胞（ＥＯＳ）聚集到气道,收集支气管肺泡灌洗液（ＢＡＬＦ０细胞并以流式细胞仪检测ＣＤ８６分子的表达水平;观察静脉注射抗ＣＤ８６单克隆抗体后ＢＡＬＦ中ＥＯＳ数和气道反应性的变化。     

哮喘豚鼠模型细支气管和肺组织的病理学研究

目的深化对哮喘小气道及肺组织病理改变的认识。方法以卵蛋白致敏法制备哮喘豚鼠模型,共设6组对照组、哮喘1日组、哮喘4日组、哮喘14日组、氟美松组及布地奈德组。观察和比较6组豚鼠大、小气道及肺泡区病理学改变及炎性细胞浸润情况。行支气管肺泡灌洗,并行细胞计数及分类。电镜观察肺泡细胞的形态。测定支气管肺泡灌洗液(BALF)中总磷脂的含量。结果各哮喘模型组豚鼠支气管黏膜上皮、基底膜、平滑肌增厚,肺泡隔较对照组显著增宽(P<0.001),肺泡腔变小;大、小气道及肺泡区有大量嗜酸粒细胞及淋巴细胞浸润;BALF中细胞总数较对照组显著增多(P<0.01),早期以中性粒细胞为主,晚期则以嗜酸粒细胞和淋巴细胞为主;电镜示肺泡Ⅱ型上皮细胞肿胀、板层体排空及部分脱落;BALF中总磷脂含量较对照组显著降低(P<0.01)。氟美松组及布地奈德组以上改变显著减轻,接近对照组。结论支气管哮喘时细支气管和肺组织也广泛存在着以嗜酸粒细胞为主的炎症;肺泡细胞在形态学改变的同时,也发生着功能的改变。     

Development of a prolonged eosinophil-rich inflammatory leukocyte infiltration in the guinea-pig asthmatic response to ovalbumin inhalation

Considerable attention has recently focused on the role of inflammation in the pathophysiology of asthma, with special emphasis on "late-phase" bronchoconstriction and increased airway hyperreactivity after antigen challenge in sensitized subjects. The present report describes the histopathologic changes in guinea-pig lung and trachea at various time intervals after ovalbumin inhalation in nonsensitized (control) and sensitized animals. Bronchoalveolar lavage (BAL) was also used to assess the accompanying accumulation of intraluminal leukocytes. A distinct leukocyte margination, consisting of neutrophils and eosinophils, was observed in the peribronchial vasculature as early as 8 min postchallenge in sensitized guinea pigs. At 6 h, the eosinophils predominated and migrated to the peribronchiolar smooth muscle layer. Between 6 h and 18 h, eosinophils were seen in tracts between the smooth muscle cell layers, accumulating in large numbers in the bronchial mucosal epithelium. This pattern persisted for at least 7 days postchallenge during which eosinophils remained the dominant cell type present. Peribronchiolar accumulation of neutrophils and mononuclear cells was minimal at all time points studied. Intraluminal mucus eosinophilia developed between 18 h and 7 days. A similar pattern of eosinophil infiltration was observed in the tracheal epithelium. Control, nonsensitized, guinea-pig lungs showed minor changes with little or no eosinophil infiltration at any time after antigen challenge. These findings correlated well with the BAL study in which sensitized guinea pigs exhibited a marked delayed increase in eosinophil counts between 18 h and 7 days compared with that in nonsensitized animals.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of cromolyn sodium and albuterol on early and late phase bronchoconstriction and airway leukocyte infiltration after allergen challenge of nonanesthetized guinea pigs

We describe the effects of the antiallergic drug cromolyn sodium and the beta 2-selective adrenoceptor agonist albuterol against early and late phase changes in specific airways conductance (sGaw) and leukocyte infiltration into the airways after allergen challenge of nonanesthetized guinea pigs. Inhalation of ovalbumin by sensitized guinea pigs induced three phases of airways obstruction: an early asthmatic response (EAR) peaking at 2 h, a late response (LAR) peaking at 17 h, and a further late response (LLAR) being observed at 72 h. The LAR was accompanied by a 13-fold rise in neutrophils and a four-fold rise in eosinophils recovered by bronchoalveolar lavage (BAL) at 17 h. By 72 h, the BAL content of neutrophils had returned to near normal, whereas eosinophil numbers had risen to 6.7-fold above baseline. Inhalation of an aerosolized solution of cromolyn, 10 mg/ml, 15 min before challenge inhibited both the EAR and LAR and the influx of neutrophils into the airways at 17 h but had no effect on eosinophil accumulation. Inhalation of cromolyn at 6 h, i.e., after the completion of the EAR, inhibited the LAR, the LLAR, and the rise in eosinophils at 72 h but did not reduce the influx of neutrophils at 17 h. Administration of cromolyn at both 15 min before and 6 h after challenge inhibited all changes in sGaw and reduced the accumulation of neutrophils at 17 h and the influx of eosinophils at 72 h. In contrast, inhalation of albuterol, 0.1 mg/ml, 15 min before allergen provocation blocked the EAR and the rise in BAL neutrophils at 17 h but did not inhibit the LAR. Inhalation of albuterol at 6 h partially reversed the LAR but had no effect on either the LLAR or cellular changes. Given at both times, albuterol inhibited the EAR and neutrophil accumulation at 17 h and partially reversed the LAR but produced no other effects.(ABSTRACT TRUNCATED AT 250 WORDS)     

Airway hyperresponsiveness to cigarette smoke in ovalbumin-sensitized guinea pigs

This study was carried out to determine if the bronchoconstrictive effect of cigarette smoke (CS) is enhanced when airway hyperresponsiveness is induced by ovalbumin (Ova) sensitization, and if so, whether an increase in endogenously released tachykinins is involved. The bronchoconstrictive effects of an acute CS inhalation challenge (15 ml; 50% concentration) were compared between guinea pigs sensitized with aerosolized Ova and matching control animals (receiving saline aerosol). In Ova-sensitized animals, there were marked increases in the numbers of eosinophils and neutrophils in the bronchoalveolar lavage fluid (BALF), which was accompanied by an elevated bronchomotor response to acetylcholine (ACh). The baseline lung resistance (RL) and dynamic pulmonary compliance (Cdyn) were not significantly different between the two groups; however, the same CS inhalation challenge evoked a significantly more intense bronchoconstriction in the Ova-sensitized group (control group: DeltaRL = 68 +/- 8%, DeltaCdyn = -26 +/- 6%; Ova group: DeltaRL = 425 +/- 76%; DeltaCdyn = -47 +/- 8%). The levels of substance P-like immunoreactivity (SP-LI) and calcitonin gene-related peptide-like immunoreactivity (CGRP-LI) measured in the bronchoalveolar lavage (BAL) collected after CS inhalation challenge were also significantly greater in Ova-sensitized animals than in control animals. Furthermore, pretreatment with SR-48968, a selective antagonist of neurokinin-2 (NK(2)) receptor, inhibited more than 85% of the enhanced bronchomotor responses to CS challenge, but did not significantly reduce the airway hyperresponsiveness to ACh in Ova-sensitized guinea pigs. These results show that Ova sensitization induces airway hyperresponsiveness to inhaled CS, and that the endogenous tachykinins evoked by CS-induced activation of lung C fibers play a primary role in this augmented response.     

Exacerbating effects of PM2.5 in OVA-sensitized and challenged mice and the expression of TRPA1 and TRPV1 proteins in lungs

Objective: To investigate the effects of particulate matter ≤ 2.5 microns (PM2.5) on asthma-related phenotypes and on lung expression of TRPA1 and TRPV1 proteins in a mouse model of asthma. Methods: Female BALB/c mice were utilized to establish 28- and 42-day asthma models. Mice were sensitized with ovalbumin (OVA) and challenged with OVA, OVA plus normal saline (NS), or OVA plus PM2.5 at two doses, 1.6 or 8.0 mg kg^?1. PM2.5 was instilled intratracheally without anesthesia. After the final OVA challenge was performed, 24 hours later, the changes in airway resistance (RI) and lung dynamic compliance (Cdyn) in response to acetylcholine chloride (ACH) were evaluated, and blood, bronchoalveolar lavage fluid (BALF) and lung tissue were taken at that time. The number of eosinophils in blood and various leukocytes in BALF were determined. Lung protein was extracted and probed for TRPA1 and TRPV1 expression. Interleukin (IL)-13, substance P (SP), prostaglandin D₂ (PGD₂) and nerve growth factor (NGF) in BALF were measured by enzyme-linked immunosorbent assay. Results: PM2.5 treated mice showed significantly greater changes in the number of inflammatory cells in blood and BALF, in RI and Cdyn in response to ACH, and in lung histopathology, indicated by inflammatory cell infiltration, thickened bronchial smooth muscles and bronchial mucosa damage, compared to controls. In addition, higher expression of TRPA1 and TRPV1 in lung and IL-13, SP, PGD₂ and NGF in BALF were seen in mice exposed to PM2.5. All effects were most pronounced in mice in the 42-day model. Conclusions: PM2.5 exacerbates effects of asthma in this model, possibly by regulating TRPA1 and TRPV1 and the relevant neurokines.     

Effect of mometasone furoate (MF)/formoterol fumarate (F) combination (MF/F) on late-phase responses in allergen-challenged Brown Norway rats

Mometasone furoate (MF)/formoterol fumarate (F) combination is a new inhaIed corticosteroid/long-acting β?-adrenergic agonist (ICS/LABA). The purpose of this study was to evaluate the effects of different dose combinations of MF/F on a variety of late-phase responses to aerosolized antigen challenge in ovalbumin sensitized Brown Norway rats. Late-phase responses were assessed by reductions in lung function, measured by forced vital capacity (FVC) and increased numbers of inflammatory cells and pro-inflammatory cytokines in the bronchoalveolar lavage (BAL) fluid of ovalbumin challenged rats. Intratracheal administration of MF/F 5 h before aerosolized ovalbumin challenge inhibited the increase in inflammatory cells, including eosinophils and levels of interleukin (IL)-4, IL-5, IL-13 and tumour necrosis factor-α (TNF-α) appearing in the bronchoalveolar lavage fluid 24 h after the antigen challenge. The combination index for inhibition of both inflammatory cells and cytokines was consistently <1 suggesting a synergistic interaction between MF and F. Intratracheal MF/F given 24 h after the aerosolized ovalbumin challenge reversed the reduction in FVC with statistically significant effects seen over a 24 h period after drug whereas MF and F alone reversed the antigen-induced reduction in FVC at selected times only. At 5 h after drug administration, when both MF and F were partially active, the combination index for MF/F was <1 suggesting a synergistic interaction between MF and F for reversal of the lung function. These results demonstrate that MF/F combination inhibits a variety of late-phase responses induced by allergen challenge and it is likely that MF/F will have a significant benefit in clinical asthma to suppress lung inflammation and improve lung function.     

An Increase in Superoxide Generation of Bronchoalveolar Lavage Fluids in the Model of Late Asthmatic Response in Guinea Pigs

To clarify the possible role of superoxide anion of bronchoalveolar cells in the pathogenesis of late asthmatic response (LAR), I performed an allergen inhalation test using a guinea pig LAR model and estimated subsequent changes in activities of superoxide generation in bronchoalveolar lavage fluids (BALFs). Significant increases in superoxide generation of BALFs occurred not only immediately, but 6 hr after ovalbumin inhalation challenge in the LAR model, and the increased levels were prolonged 24 hr later. The present results suggest that significant increases in superoxide anion of the respiratory cells were involved in the antigen-induced late responsiveness of bronchial asthma.     

S-carboxymethylcysteine normalises airway responsiveness in sensitised and challenged mice.

S-carboxymethylcysteine (S-CMC) has been used as a mucoregulator in respiratory diseases. However, the mechanism of action of S-CMC on allergic airway inflammation has not yet been defined. In the present study, BALB/c mice were initially sensitised and challenged to ovalbumin (OVA) and, weeks later, re-challenged with OVA (secondary challenge). S-CMC (5-100 mg.kg-1) was administered from 2 days before the secondary challenge through to the day of assay. Mice developed airway hyperresponsiveness (AHR) 6 h after the secondary challenge and increased numbers of neutrophils were present in the bronchoalveolar lavage (BAL) fluid. At 72 h after secondary challenge, mice again developed AHR, but the BAL fluid contained large numbers of eosinophils. S-CMC treatment was found to reduce AHR and neutrophilia at 6 h, as well as eosinophilia and AHR at 72 h. These effects appeared to be dose dependent. Goblet cell hyperplasia, observed at 72 h, was reduced by S-CMC. In BAL fluid, increased levels of interferon-gamma, interleukin (IL)-12 and IL-10 and decreased levels of IL-5 and IL-13 were detected. In conclusion, the data indicate that S-carboxymethylcysteine is effective in reducing airway hyperresponsiveness and airway inflammation at two distinct phases of the response to the secondary allergen challenge in sensitised mice.     

哮喘豚鼠肺组织中嗜酸细胞凋亡与白细胞介素5mRNA表达？…

目的 探讨哮喘时嗜酸细胞（ＥＯＳ）凋亡与肺组织白细胞介素５（ＩＬ－５）ｍＲＮＡ表达的关系。方法 将豚鼠随机分为对照组（正常组７只）、哮喘组（８只）、地塞米松组（８只），应用脱氧核糖核酸末端转移酶介导的缺口末端标记（ＴＵＮＥＬ）技术和原位杂交方法，检测支气管肺泡灌洗液（ＢＡＬＦ）中不同密度ＥＯＳ凋亡百分比和肺组织ＩＬ－５ｍＲＮＡ的表达。结果 （１）正常对照组ＢＡＬＦ中低密度ＥＯＳ、正常密度ＥＯＳ凋是     

豚鼠中性粒细胞性哮喘模型的建立

目的建立豚鼠中性粒细胞性哮喘模型。方法 40只成年雄性豚鼠按随机数字表法分为对照组（A组）、嗜酸粒细胞性哮喘组（B组）、中性粒细胞性哮喘组（C组）、嗜酸粒细胞性哮喘治疗组（D组）和中性粒细胞性哮喘治疗组（E组）。用卵白蛋白（ovalbumin,OVA）和弗氏完全佐剂（Freund’s complete adjuvant,FCA）联合致敏或OVA单独致敏豚鼠后用OVA雾化吸入激发建立中性粒细胞性哮喘或嗜酸粒细胞性哮喘模型,治疗组在激发前腹腔注射地塞米松。观察各组豚鼠雾化激发后体征变化及支气管肺组织病理改变,并比较各组豚鼠气道阻力、血中白细胞分类计数、支气管肺泡灌洗液（brochial alveolar lavage fiuid,BALF）细胞总数及分类计数。结果 B、C组豚鼠激发后均出现典型哮喘症状,不同浓度乙酰甲胆碱激发后的气道阻力与A组相比均显著增高（P〈0.05）;B组豚鼠BALF总数、BALF及血中嗜酸粒细胞所占比例与A组比较显著增加（P〈0.05）;C组豚鼠BALF总数、BALF及血中中性粒细胞所占比例与A组比较均显著增加（P〈0.05）;C组豚鼠BALF中性粒细胞所占比例与B组相比显著增加（P〈0.05）;除B、D组血中性粒细胞外,D和E两组的上述其他各项指标分别与B组和C组相比明显降低（P〈0.05）,以上差异均有统计学意义。B、C两组豚鼠支气管肺组织病理均提示支气管管腔狭窄、黏膜上皮脱落、炎症细胞浸润等典型的哮喘病理学改变,其中B组以嗜酸粒细胞浸润为主,C组以中性粒细胞浸润为主,D、E组较之明显好转。结论本实验建立的豚鼠中性粒细胞性哮喘模型是成功的。     

Development and characterisation of a novel and rapid lung eosinophil influx model in the rat

Eosinophils play a major role in the development and severity of asthma. Robust and rapid preclinical animal models are desirable to profile novel therapeutics inhibiting the influx of eosinophils into the airways. To develop a rapid, airway eosinophil recruitment model in the rat, Brown-Norway (BN) rats were immunised with ovalbumin (OVA)/alum on day 0, 1 and 2 and challenged with OVA aerosol on day 5 and 6. On day 7 bronchoalveolar lavage fluid (BALF) was analysed for eosinophil numbers, eosinophil peroxidase (EPO) activity and cytokines. Lung sections were also examined. The immunised animals showed a strong selective influx of eosinophils into the airways correlating with enhanced EPO activity, Interleukin (IL-4), IL-5 and monocytes chemo attractant protein levels in the BALF in comparison to sham-sensitised rats. In addition the immunised rats developed goblet cell metaplasia in the lung and showed OVA specific IgG1 and IgE levels in the serum but no airway hyperreactivity after metacholine challenge. Airway inflammation was suppressed by applying the steroids Budesonide (intra tracheally) and Prednisolone (per orally), Roflumilast a phosphodiesterase-4 inhibitor, and the H1 receptor antagonists Epinastine and Ketotifen. Montelukast, a Leukotriene receptor antagonist and Chromoglycate, a mast cell stabiliser, had no effect in this model. In summary, in this novel preclinical rat model therapeutics expected to inhibit the development of airway eosinophilia can rapidly be tested.     

Nitric oxide and protein nitration are eosinophil dependent in allergen-challenged mice

To explore the possible role of eosinophils in NO-mediated tissue injury, we studied a murine model of allergic asthma. Male A/J mice were sensitized and challenged intranasally with ovalbumin (OVA). Following challenge, the number of eosinophils in bronchoalveolar lavage fluid (BALF) increased from 0.4% of total cells at baseline (0.02 x 10(4) cells/ml) to 60.2% at 48 h after the challenge (9.34 x 10(4) cells/ml). The rise in eosinophil count was accompanied by a 40.3% increase in total NO(2-) plus NO(3-) (NO(x)) in BALF. This in turn was accompanied by expression of inducible NO synthase (NOS II) in airway epithelial and inflammatory cells, as well as by evidence of staining for 3-nitrotyrosine (3NT) in peribronchial inflammatory cells and at the epithelial surface. Both NO(x) production and 3NT were significantly reduced by pretreatment of the challenged mice with the highly specific NOS II inhibitor N-3-aminomethyl-benzyl-acetamidine-dihydrochloride (1400W), as well as by the nonselective NOS inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME). L-NAME and 1400W also reduced the number of BALF eosinophils (37.2% and 61.5%, respectively, as compared with the control value), suggesting that NO production by NOS II contributes to eosinophil recruitment. To further examine the role of eosinophils, we pretreated additional mice with an anti-interleukin (IL)-5 antibody, which reduced BALF eosinophilia following OVA challenge by 90.1%. In concert with the decrease in eosinophils, the anti-IL-5 antibody reduced NO(x) in BALF almost to the baseline value, and decreased the number of 3NT-positive cells in the peribronchial region by 74.4%. Western blot analysis of protein extracted from whole lung confirmed the reduction in tyrosine nitration by anti-IL-5 antibody. These findings indicate that NO and eosinophilic inflammation are closely coupled, and suggest that eosinophils are an important source of tyrosine nitration.     

Anti-interleukin-9 antibody treatment inhibits airway inflammation and hyperreactivity in mouse asthma model

Numerous in vitro and in vivo studies in both animals and patients with asthma have shown that interleukin (IL)-9 is an important inflammatory mediator in asthma. To examine the effects of IL-9 antagonism on airway inflammation, ovalbumin-sensitized BALB/c mice were intravenously given anti-IL-9 antibody or an isotype-matched control antibody 30 minutes before challenge with aerosolized ovalbumin. Airway response to methacholine was measured, and samples of bronchoalveolar lavage fluid (BALF) were obtained 24 hours after the last antigen challenge. Lung tissue was harvested and examined histopathologically. After ovalbumin challenge, there were significant increases in airway hyperreactivity, the numbers of inflammatory cells in lung, and IL-4, IL-5, and IL-13 production in BALF. Treatment with anti-IL-9 antibody significantly prevented airway hyperreactivity in response to methacholine inhalation. Blockade of IL-9 reduced the numbers of eosinophils (0.3 +/- 0.1 x 10(5) and 23.6 +/- 0.5 x 10(5)/ml, anti-IL-9 antibody/control immunoglobulin G) and lymphocytes (0.2 +/- 0.2 x 10(5) and 0.8 +/- 0.1 x 10(5)/ml) in BALF. Anti-IL-9 antibody treatment also reduced the concentrations of IL-4 (from 70.6 +/- 4.6 to 30.8 +/- 5.2 pg/ml), IL-5 (from 106.4 +/- 12 to 54.4 +/- 6.6 pg/ml), and IL-13 (from 44.2 +/- 7.6 to 30.1 +/- 5.5 pg/ml) in BALF. Macrophage-derived cytokine expression in the airways was also decreased by IL-9 blockade. Taken together, our findings emphasize the importance of IL-9 in the pathogenesis of asthma and suggest that blockade of IL-9 may be a new therapeutic strategy for bronchial asthma.     

The role of eosinophils, neutrophils and lymphocytes for the development of bronchial hyperresponsiveness in a guinea pig model of asthma

To elucidate the role of eosinophils, neutrophils and lymphocytes for the development of bronchial hyperresponsiveness (BHR) following antigen exposure, we have developed a guinea pig model of BHR. Guinea pigs immunized by repeated exposure to aerosolized ovalbumin (OA) were intravenously given metopirone, a cortisol synthesis inhibitor, 24 hrs before and 30 min before antigen challenge, and to prevent death from immediate severe bronchoconstriction, chlorpheniramine maleate was also injected. After antigen challenge with high dose of OA, LAR occurred in twelve of fifteen animals (80%) and the bronchial responsiveness to acetylcholine (Ach) was significantly increased. Histologic examination at 72 h showed a significant increase in the number of eosinophils but not neutrophils within the tracheal walls. However, there was no significant correlation between the change in bronchial responsiveness to Ach at 24 h and the number of eosinophil in the tracheal wall at 72 h. When guinea pigs were treated with Cyclosporin A or FK506, T-lymphocyte selective immunosuppressive agents, from the beginning of immunization period, both eosinophil infiltration and an increase in bronchial responsiveness were inhibited. These results suggest that eosinophils and T-lymphocytes may play an important role in the development of bronchial hyperresponsiveness.     

雷公藤甲素对支气管哮喘小鼠STAT-1与ICAM-1表达的影响

目的 研究雷公藤甲素对支气管哮喘（简称哮喘）小鼠肺组织中信号转导和转录激活因子-1（STAT-1）与细胞间黏附分子-1（ICAM-1）表达的影响,探讨其治疗哮喘的机制.方法 40只雄性昆明小鼠随机分成4组：正常对照组、哮喘组、地塞米松治疗组及雷公藤甲素治疗组,以卵清蛋白致敏和激发方法建立哮喘小鼠动物模型并给予相应治疗.24 d后处死小鼠,检测BALF中白细胞总数及嗜酸粒细胞（EOS）计数;采用逆转录-聚合酶链反应（RT-PCR）方法检测肺组织中STAT-1、ICAM-1 mRNA表达水平;采用免疫组织化学法检测肺组织中STAT-1、ICAM-1蛋白表达水平.结果 哮喘组STAT-1、ICAM-1 mRNA及蛋白表达明显高于正常对照组（P＜0.01）,雷公藤甲素治疗组及地塞米松组明显低于哮喘组（P＜0.01）.肺组织STAT-1蛋白的表达与BALF中白细胞数、EOS计数及肺组织ICAM-1蛋白表达呈正相关（r分别为0.665,0.735,0.677,P＜0.01）.肺组织ICAM-1蛋白表达与白细胞总数、EOS计数呈正相关（r分别为0.792,0.776,P＜0.01）.结论 雷公藤甲素抑制哮喘气道炎症的机制可能与其抑制STAT-1与ICAM-1的表达活性有关.     

地塞米松对哮喘豚鼠嗜酸细胞中白细胞介素3、5及粒-巨噬细胞集落刺激因子受体表达的影响

目的观察地塞米松(DM)对嗜酸细胞(EOS)上白细胞介素5受体α(IL-5Rα)、白细胞介素3受体α(IL-3Rα)、粒-巨噬细胞集落刺激因子受体α(GM-CSFRα)及共同β链(βcR)mRNA表达的影响,探讨糖皮质激素促进哮喘EOS凋亡的机制.方法18只健康豚鼠随机分为正常组、哮喘组、地塞米松组,每组6只,以卵蛋白致敏激发制作哮喘豚鼠模型,密度梯度分离法分离支气管肺泡灌洗液(BALF)中的低密度EOS(HEOS)及正常密度EOS(NEOS),以末端脱氧核糖核苷酸转移酶介导的dUTP缺口末端标记法(TUNEL)法检测细胞凋亡,原位杂交检测各受体mRNA表达,逆转录-多聚酶链式反应(RT-PCR)法检测EOSIL-5Rα、IL-3Rα相对含量.结果HEOS及NEOS凋亡,哮喘组(4.0±2.0、3.0±2.0)与正常组(8.0±2.0、7.0±2.0)比较差异有显著性(P＜0.01),而细胞数哮喘组(75.2±12.6、50.7±11.2)与正常组(4.8±1.5、9.5±2.6)比较差异也有显著性(P＜0.01).用DM2h后不同密度EOS数量(14.8±8.3、20.0±7.0)与哮喘组比较差异有显著性(P＜0.01),DM组以HEOS下降为明显(P＜0.05),BALF中EOS以NE0S为主,EOS凋亡DM组(24.0±5.0、22.0±4.0)与哮喘组比较差异有显著性(P＜0.01);EOS表达IL-5、IL-3及GM-CSFα受体mRNA,哮喘组与正常组比较差异有显著性(P＜0.01,0.05),DM组与哮喘组比较差异有显著性(P＜0.05或0.01);而βcR表达哮喘组(41±6、39±7)与正常组(28±5、26±5)比较差异有显著性(P＜0.01);DM组(32±8、30±5)与哮喘组比较差异有显著性(P＜0.05).HEOS表达各受体与NEOS比较差异无显著性(P＞0.05);RT-PCR检测显示,DM组IL-5Rα、IL-3RαmRNA与哮喘组比较差异均有显著性(P＜0.01,0.05).结论DM可促进哮喘豚鼠肺内EOS凋亡,减少肺内EOS浸润,DM可通过促进IL-5、IL-3、GM-CSF受体各自α链表达,抑制这三种受体的共同β链表达,减少其生物学功能,促进EOS凋亡.     

支气管哮喘急性发作期激活转录因子-3的表达及作用

目的探讨支气管哮喘（简称哮喘）急性发作期激活转录因子-3（ATF3）的表达及作用。方法 30只健康雄性豚鼠,按随机数字表法分为对照组（A组）、哮喘组（B组）及地塞米松治疗组（C组）,每组10只。卵清蛋白致敏法复制哮喘模型。收集支气管肺泡灌洗液（BALF）并进行细胞总数及分类计数;观察豚鼠肺组织病理学改变;检测豚鼠肺组织及BALF中ROS含量;采用免疫组织化学和Westernblot法测定豚鼠肺组织中ATF3蛋白的表达和量的变化;原位杂交、RT-PCR法检测ATF3 mRNA的表达变化;免疫细胞化学检测豚鼠BALF细胞中ATF3蛋白的表达。结果①哮喘组豚鼠BALF中炎细胞总数、嗜酸粒细胞百分比（EOS%）显著高于对照组（P〈0.01）,哮喘组豚鼠肺组织可见大量炎症细胞浸润及明显气道重塑改变,且哮喘组ROS含量显著升高,而地塞米松治疗组上述变化明显减低（P值均〈0.01）;②ATF3蛋白及mRNA表达哮喘组明显高于对照组（P值均〈0.01）;③ATF3蛋白及mRNA的表达变化与ROS含量及BALF炎细胞总数、EOS%变化均呈正相关。结论哮喘急性发作期豚鼠肺组织及BALF细胞中ATF3的表达升高,可能与气道炎症反应和氧化应激有关;给予地塞米松治疗后ATF3表达下降,可能在哮喘的防治中起重要作用。