Cigarette smoke-induced airway hyperresponsiveness is not dependent on elevated immunoglobulin and eosinophilic inflammation in a mouse model of allergic airway disease

Epidemiologic studies suggest that children raised in homes of cigarette smokers have a higher incidence of asthma than children who are raised in homes of nonsmokers. We sought to develop an experimental model to understand the mechanisms involved. Female BALB/c mice were paired with male DO11.10 ovalbumin (OVA)-T cell receptor hemizygous (+/-) mice such that the offspring were either transgene positive (+/-) or negative (-/-). Mice were exposed to either air or mainstream cigarette smoke (100 mg/m(3) total particulate matter, 6 hours/day, 7 days/week) during pregnancy. Immediately after birth, newborn mice were exposed for 4 weeks to either air or sidestream cigarette smoke (SS; 5 mg/m(3) total particulate matter, 6 hours/day, 5 days/week) and then exposed for the following 6 weeks to either air, SS, OVA (5 mg/m(3), 6 hours/day, 5 days/week) or a combination of OVA-SS. DO11.10 +/- offspring exposed to OVA had increased airway hyperresponsiveness (AHR) to methacholine challenge, total IgE, OVA-specific IgE and IgG(1), lymphocytes, and neutrophils in bronchoalveolar lavage and perivascular and peribronchiolar inflammation. Exposure to SS alone caused a significant increase in AHR in both +/- and -/- mice. Transgene -/- mice did not exhibit AHR after OVA exposure unless it was delivered in combination with SS. When compared with OVA-only exposure, OVA-SS exposure decreased total IgE, OVA-specific IgE, and IgG(1) amounts in +/- mice. These results indicate that exposure to SS after birth enhanced AHR in offspring that are both predisposed (+/-) and nonpredisposed (-/-) to develop an allergic response to OVA, but this AHR was not associated with elevated lung eosinophilia or OVA-specific Ig amounts.     

Smoking and pediatric respiratory health

Many children are exposed to smoking both prenatally and postnatally. Prenatal exposure to mainstream smoke from the mother and even to environmental tobacco smoke (ETS) from the mother in utero has been shown to change fetal lung development and cause airflow obstruction and airway hyperresponsiveness. Children exposed to ETS postnatally have more symptoms of cough, wheeze, respiratory illnesses, decreases in lung function, and increases in airway responsiveness. Smoke exposure is associated with the early development of asthma, increased severity of asthma, and the development of allergy. Finally smoke exposure is associated with sudden infant death and airway obstruction. This article reviews the spectrum of effects of cigarette smoke exposure on the respiratory health of infants and children and highlights basic science research exploring the mechanisms of these effects.     

香烟烟雾暴露对支气管哮喘大鼠CD4+ CD25+调节性T细胞及转录因子Foxp3表达的影响

目的 探讨香烟烟雾暴露对支气管哮喘(简称哮喘)大鼠CD4+CD25+调节性T细胞(Treg)数量及转录因子Foxp3表达的影响.方法 将40只雄性Wistar大鼠按随机数字表法分为生理盐水组、烟雾暴露组、哮喘组和哮喘+烟雾暴露组,每组10只;哮喘组采用卵清白蛋白(OVA)致敏并吸入激发制备哮喘模型,生理盐水组雾化生理盐水,烟雾暴露组采用吸入香烟烟雾,哮喘+烟雾暴露组于每日雾化激发OVA前给予香烟烟雾吸入.流式细胞仪检测外周血CD4+ CD25+Treg细胞占CD4+T细胞的比例,酶联免疫吸附试验(ELISA)检测外周血和肺组织γ干扰素(INF-γ)以及白细胞介素4(IL-4)含量;Western blot检测肺组织Foxp3蛋白表达水平.结果 (1)哮喘组大鼠CD4+CD25+Treg为(6.4±1.0)%,低于生理盐水组的(9.9±1.0)%,差异有统计学意义(F=92.59,P＜0.01);哮喘+烟雾暴露组为(3.3±0.8)%,低于生理盐水组和哮喘组,差异有统计学意义(F=92.59,P＜0.01).(2)哮喘组大鼠血浆和肺组织中IL-4含量[(22.6±4.3)ng/L、(0.8±0.1)ng/L]高于生理盐水组[(11.4±2.9)ng/L、(0.3±0.1)ng/L],差异有统计学意义(F值分别31.69和49.29,P＜0.01);哮喘+烟雾暴露组血浆和肺组织中IL-4含量[(34.1±6.1)ng/L、(1.4±0.3)ng/L]高于生理盐水组和哮喘组,差异有统计学意义(F值分别为31.69和49.29,P＜0.05);哮喘组血浆中INF-γ含量[(59±20)ng/L]低于生理盐水组[(151±56)ng/L],差异有统计学意义(F=21.83,P＜0.05),哮喘+烟雾暴露组INF-γ含量[(10±3)ng/L]低于生理盐水组和哮喘组,差异有统计学意义(F=21.83,P＜0.05).(3)哮喘组Foxp3蛋白表达为8.18±0.26,低于生理盐水组的10.27±0.33(F=43.33,P＜0.01);哮喘+烟雾暴露组为6.36±0.38,低于生理盐水组和哮喘组(F=43.33,P＜0.05).结论 香烟烟雾暴露可能通过下调CD4+CD25+Treg数量并抑制Foxp3蛋白表达,进一步加重哮喘的Th1/Th2失衡.     

Increased airway responsiveness and decreased alveolar attachment points following in utero smoke exposure in the guinea pig

Maternal smoking during pregnancy has been shown to result in abnormalities in lung function in newborn infants, including reduced expiratory flow and increased airway responsiveness to inhaled agonists. The mechanisms by which this occurs remain unclear. Using a guinea pig model of in utero smoke exposure, we measured airway responsiveness and lung morphology in a group of neonatal guinea pigs 21 d after delivery. Pregnant guinea pigs were exposed to cigarette smoke from Day 28 to term (Day 68 of gestation). After delivery newborn animals did not receive any smoke exposure. Airway wall thickness, smooth muscle area, and the number of points where the alveoli attached to the airway adventitia were measured. Airway responsiveness was increased (p < 0.05) and the mean distance between alveolar attachment points was increased (mean 0.052 +/- SE 0.001 mm versus 0.046 +/- 0.001, p = 0.001) in animals exposed to cigarette smoke in utero compared with nonexposed animals. Although not statistically significant, both the inner and outer airway wall and the smooth muscle area were greater in exposed animals compared with nonexposed animals. The increased mean distance between alveolar attachments in the smoke-exposed group was the result of a reduction in the number of attachments and an increase in the outer airway wall perimeter. These findings suggest that the increased airway responsiveness observed in postnatal animals, subsequent to in utero cigarette smoke exposure, may be the result of decreased alveolar attachment points to the airways and changes in airway dimensions.     

Prenatal cigarette smoke decreases lung cAMP and increases airway hyperresponsiveness

Epidemiologic studies suggest that in utero exposure to tobacco smoke, primarily through maternal smoking, increases the risk for asthma in children; however, the mechanism of this phenomenon is not clear. Cyclic adenosine monophosphate relaxes airway smooth muscles in the lung and acts as an antiasthmatic. In this study, we examined the effects of in utero cigarette smoke exposure of Balb/c mice on airway responsiveness, as determined by Penh measurements. Animals exposed prenatally but not postnatally to cigarette smoke exhibited increased airway hyperresponsiveness after a single intratracheal injection of Aspergillus fumigatus extract. The increased airway hyperresponsiveness was not associated with increased leukocyte migration or mucous production in the lung but was causally related to decreased lung cyclic adenosine monophosphate levels, increased phosphodiesterase-4 enzymatic activity, and phosphodiesterase-4D (PDE4D) isoform-specific messenger ribonucleic acid expression in the lung. Exposure of adult mice to cigarette smoke did not significantly alter airway responsiveness, cyclic adenosine monophosphate levels, or the phosphodiesterase activity. These results suggest that prenatal exposure to cigarette smoke affects lung airway reactivity by modulating the lung cyclic adenosine monophosphate levels through changes in phosphodiesterase-4D activity, and these effects are independent of significant mucous production or leukocyte recruitment into the lung.     

Time course of cigarette smoke-induced pulmonary inflammation in mice.

Inflammation of the airways and lung parenchyma plays a major role in the pathogenesis of chronic obstructive pulmonary disease. In the present study a murine model of tobacco smoke-induced emphysema was used to investigate the time course of airway and pulmonary inflammatory response, with a special emphasis on pulmonary dendritic cell (DC) populations. Groups of mice were exposed to either cigarette smoke or to control air for up to 24 weeks. In response to cigarette smoke, inflammatory cells (i.e. neutrophils, macrophages and lymphocytes) progressively accumulated both in the airways and lung parenchyma of mice. Furthermore, a clear infiltration of DCs was observed in airways (10-fold increase) and lung parenchyma (1.5-fold increase) of cigarette-exposed mice at 24 weeks. Flow cytometric analysis of bronchoalveolar lavage (BAL) DCs of smoke-exposed mice showed upregulation of major histocompatability complex II molecules and costimulatory molecules CD40 and CD86, compared with BAL DCs of air-exposed mice. Morphometric analysis of lung histology demonstrated a significant increase in mean linear intercept and alveolar wall destruction after 24 weeks of smoke exposure. In conclusion, the time course of the changes in inflammatory and dendritic cells in both bronchoalveolar lavage and the pulmonary compartment of cigarette smoke-exposed mice was carefully characterised.     

Tobacco Smoke is an Adjuvant for Maintained Airway Sensitization in Guinea Pigs

Tobacco smoke (TS) exposure exacerbates asthma and may induce airway hyperresponsiveness in asymptomatic individuals. We hypothesized that TS exposure is an adjuvant to airway responsiveness. Ovalbumin (OA) sensitized guinea pigs were TS or air exposed. At 30 exposure days OA airway responsiveness was demonstrable in OA-treated animals exposed to either TS or air. After 130 exposure days only TS-exposed guinea pigs demonstrated OA airway responsiveness. Capsaicin airway responsiveness developed in non-sensitized and OA-sensitized guinea pigs exposed to TS. Therefore TS-exposure acts as an adjuvant to antigenic and neurogenic airway responsiveness. Combined antigen and adjuvant avoidance may attenuate or reverse airway responsiveness.     

Combined effects of ozone and cigarette smoke on airway responsiveness and vascular permeability in guinea pigs

The effects of combined exposure to ozone and cigarette smoke on airway responsiveness and tracheal vascular permeability, compared with those of single exposure were examined in guinea pigs. Airway responsiveness was assessed by measuring the specific airway resistance (sRaw) as a function of increasing concentration of inhaled methacholine aerosol immediately, 5 hr, and 24 hr after exposure. In a parallel study, tracheal vascular permeability was quantified by measuring the tracheal extravasation of intravenously administered Evans blue dye. Neither exposure to 1 ppm ozone for 30 min nor 5 puffs of cigarette smoke increased airway responsiveness or vascular permeability at any time after exposure. Combined exposure to 1 ppm ozone for 30 min and 5 puffs of cigarette smoke caused airway hyperresponsiveness and increased vascular permeability immediately after exposure. Exposure to 1 ppm ozone for 90 min increased both airway responsiveness and vascular permeability immediately after exposure. Exposure to 10 puffs of cigarette smoke increased airway responsiveness but not vascular permeability immediately after exposure. Combined exposure to 1 ppm ozone for 90 min and 10 puffs of cigarette smoke increased both airway responsiveness and vascular permeability immediately after exposure. The combined exposure to ozone and cigarette smoke thus increased both airway responsiveness and tracheal vascular permeability to a greater extent than did exposure to a single agent, suggesting that a combination of air pollutants has a more deleterious effect both on airway responsiveness and on tracheal vascular permeability than does either agent alone in guinea pigs. Offprint requests to: T. Okubo     

Tobacco Smoke is an Adjuvant for Maintained Airway Sensitization in Guinea Pigs

Tobacco smoke (TS) exposure exacerbates asthma and may induce airway hyperresponsiveness in asymptomatic individuals. We hypothesized that TS exposure is an adjuvant to airway responsiveness. Ovalbumin (OA) sensitized guinea pigs were TS or air exposed. At 30 exposure days OA airway responsiveness was demonstrable in OA-treated animals exposed to either TS or air. After 130 exposure days only TS-exposed guinea pigs demonstrated OA airway responsiveness. Capsaicin airway responsiveness developed in non-sensitized and OA-sensitized guinea pigs exposed to TS. Therefore TS-exposure acts as an adjuvant to antigenic and neurogenic airway responsiveness. Combined antigen and adjuvant avoidance may attenuate or reverse airway responsiveness.     

Acute exposure to cigarette smoke induces airway hyperresponsiveness without airway inflammation in guinea pigs. Dose-response characteristics

We examined whether acute exposure to a low dose of cigarette smoke causes an increase in airway responsiveness in guinea pigs and whether the changes in airway responsiveness are accompanied by increased vascular permeability or neutrophil influx in the trachea. Animals were divided into four groups: groups exposed to 5, 10, or 20 puffs of cigarette smoke and a control group. Airway responsiveness was assessed by measuring specific airway resistance (SRaw) as a function of increasing concentration of inhaled methacholine (Mch) aerosol immediately, 5 h, and 24 h after exposure. In parallel studies, tracheal vascular permeability was quantified by measuring the tracheal extravasation of intravenously administered Evans blue dye, and neutrophil influx into the tracheal mucosa was quantified by counting cells within whole mounts of tracheas that were stained with Giemsa. Exposure to 5 puffs of cigarette smoke caused no changes in airway responsiveness. Exposure to 10 puffs induced airway hyperresponsiveness only immediately after exposure. Exposure to 20 puffs induced airway hyperresponsiveness not only immediately but also 5 h after exposure. There was a significant correlation between the dose (puffs) of cigarette smoke and increase in airway responsiveness immediately after exposure (r = 0.77; p less than 0.001). The tracheal extravasation of intravenously administered Evans blue dye and the number of neutrophils in the tracheal mucosa did not differ significantly from the corresponding control values at any time or in any exposed group. Furthermore, none of these changes was observed in the airways distal to the trachea of any animal immediately after exposure to 20 puffs of cigarette smoke.(ABSTRACT TRUNCATED AT 250 WORDS)     

香烟烟雾暴露对支气管哮喘大鼠Th1/Th2细胞因子及转录因子GATA-3表达的影响

目的 通过观察香烟烟雾暴露后支气管哮喘(简称哮喘)大鼠Th1/Th2细胞因子及转录因子GATA-3表达的变化.探讨吸烟加重哮喘的免疫学机制.方法 48只雄性Wistar大鼠随机分为对照组、烟雾暴露组、哮喘组、哮喘+烟雾暴露组;建立慢性哮喘大鼠模型和哮喘大鼠香烟烟雾暴露模型,普通病理观察气道壁厚度的变化,酶联免疫吸附试验检测外周血和肺组织γ干扰素(INF-γ)和白介素4(IL-4)含量;免疫印迹检测肺组织GATA-3蛋白表达水平.结果 ①哮喘+烟雾暴露组气道壁厚度[(18.34±0.87)μm 2/μm]较哮喘组[(15.72±0.82)μm 2/μm]和对照组[(8.52±0.58)μm 2/μm]均明显增加,差异有统计学意义(P值均<0.01);②哮喘+烟雾暴露组血浆和肺组织IL-4含量[(34.07±6.11)ng/L]、[(1.41±0.31)ng/L]较哮喘组[(22.57±4.32)ng/L]、[(0.80±0.14)ng/L]和对照组[(11.38±2.90)ng/L]、[(0.27±0.08)ng/L]均增高,差异有统计学意义(P值均<0.05);哮喘+烟雾暴露组血浆INF-γ含量[(9.53±3.28)ng/L]较哮喘组[(58.83±19.57)ng/L]和对照组[(150.87±55.54)ng/L]均降低,差异有统计学意义(P值均<0.05),肺组织INF-γ含量[(0.48±0.10)ng/L]较哮喘组[(0.58±0.23)ng/L]差异无统计学意义;③哮喘+烟雾暴露组GATA-3蛋白表达(1.29±0.08)较哮喘组(0.87±0.04)和对照组(0.45±0.06)均增加,差异有统计学意义(P值均<0.01).结论 香烟烟雾暴露可以通过上调转录因子GATA-3蛋白表达,进而调控Th1/Th2偏移,在哮喘气道炎症及气道重塑的形成中扮演重要角色,为吸烟加重哮喘的免疫学机制之一.     

Importance of myeloid dendritic cells in persistent airway disease after repeated allergen exposure

RATIONALE: There is conflicting information about the development and resolution of airway inflammation and airway hyperresponsiveness (AHR) after repeated airway exposure to allergen in sensitized mice. METHODS: Sensitized BALB/c and C57BL/6 mice were exposed to repeated allergen challenge on 3, 7, or 11 occasions. Airway function in response to inhaled methacholine was monitored; bronchoalveolar lavage fluid inflammatory cells were counted; and goblet cell metaplasia, peribronchial fibrosis, and smooth muscle hypertrophy were quantitated on tissue sections. Bone marrow-derived dendritic cells were generated after differentiation of bone marrow cells in the presence of growth factors. RESULTS: Sensitization to ovalbumin (OVA) in alum, followed by three airway exposures to OVA, induced lung eosinophilia, goblet cell metaplasia, mild peribronchial fibrosis, and peribronchial smooth muscle hypertrophy; increased levels of interleukin (IL)-4, IL-5, IL-13, granulocyte-macrophage colony-stimulating factor, transforming growth factor-beta(1), eotaxin-1, RANTES (regulated on activation, normal T-cell expressed and secreted), and OVA-specific IgG1 and IgE; and resulted in AHR. After seven airway challenges, development of AHR was markedly decreased as was the production of IL-4, IL-5, and IL-13. Levels of IL-10 in both strains and the level of IL-12 in BALB/c mice increased. After 11 challenges, airway eosinophilia and peribronchial fibrosis further declined and the cytokine and chemokine profiles continued to change. At this time point, the number of myeloid dendritic cells and expression of CD80 and CD86 in lungs were decreased compared with three challenges. After 11 challenges, intratracheal instillation of bone marrow-derived dendritic cells restored AHR and airway eosinophilia. CONCLUSIONS: These data suggest that repeated allergen exposure leads to progressive decreases in AHR and allergic inflammation, through decreases in myeloid dendritic cell numbers.     

Airway alveolar attachment points and exposure to cigarette smoke in utero

The harmful effects of in utero cigarette smoke exposure include increased asthma symptoms and reduced lung function during the neonatal period, increased airway responsiveness to inhaled stimuli, and an increased risk of sudden infant death syndrome. Altered lung function may result from altered airway/lung structure. Airway dimensions, alveolar attachment points, and parenchymal elastin content were measured in 32 infants who died from sudden infant death syndrome and were grouped according to their perinatal cigarette smoke exposure. Compared with those without any exposure to cigarette smoke, the distance between alveolar attachments on airways was greater (p < 0.001) in infants exposed to cigarette smoke only in utero or both in utero and during the postnatal period but not different in those with only postnatal exposure. The percentage of elastin within the alveolar walls was similar in all the exposure groups. These findings suggest that in utero cigarette smoke exposure may result in abnormal airway function due to a reduction of the forces opposing airway narrowing.     

Genetic variability in pulmonary physiological, cellular, and antibody responses to antigen in mice.

Wide differences among inbred mouse strains in susceptibility to develop components of asthmalike pulmonary changes would provide insights into the nature of the relationships among those components and set the stage for genetic approaches to their etiology. We therefore examined pulmonary pathophysiological and serum immunoglobulin (Ig)E responses in mice of 12 inbred strains sensitized intraperitoneally with ovalbumin (OVA) and repeatedly exposed to aerosolized OVA. One day after the last OVA exposure the intravenous methacholine (MCh) dose required to reduce lung conductance by 50% (ED(50)GL) in OVA-sensitized and exposed mice was reduced by 0 to 2.7-fold, compared with sham-sensitized mice, depending on the strain. In OVA-sensitized mice, bronchoalveolar lavage (BAL) eosinophils comprised from 3.3 +/- 3.1 (SD) to 91.2 +/- 5.0% of BAL cells and eosinophilic pulmonary inflammation varied from being nondetectable to widespread and severe. OVA-specific IgE concentrations ranged from less than 3 ng/ml to 455 ng/ml in different strains. Shifts in responsiveness correlated significantly with pulmonary eosinophilia among strains (r > 0.70, p < 0.001) but not with antigen-specific IgE levels (r = 0.55, p = 0.056). These results demonstrate that allergen- induced enhancement of cholinergic responsiveness, pulmonary eosinophil influx, and elevations of serum antigen-specific IgE levels are each genetically determined and are not always associated.     

Hybrid malondialdehyde and acetaldehyde protein adducts form in the lungs of mice exposed to alcohol and cigarette smoke

Background: Most alcohol abusers smoke cigarettes and approximately half of all cigarette smokers consume alcohol. However, no animal models of cigarette and alcohol co‐exposure exist to examine reactive aldehydes in the lungs. Cigarette smoking results in elevated lung acetaldehyde (AA) and malondialdehyde (MDA) levels. Likewise, alcohol metabolism produces AA via the action of alcohol dehydrogenase and MDA via lipid peroxidation. A high concentration of AA and MDA form stable hybrid protein adducts known as malondialdehyde–acetaldehyde (MAA) adducts. We hypothesized that chronic cigarette smoke and alcohol exposure in an in vivo mouse model would result in the in vivo formation of MAA adducts. Methods: We fed C57BL/6 mice ad libitum ethanol (20%) in drinking water and exposed them to whole‐body cigarette smoke 2 h/d, 5 d/wk for 6 weeks. Bronchoalveolar lavage fluid and lung homogenates were assayed for AA, MDA, and MAA adduct concentrations. MAA‐adducted proteins were identified by Western blot and ELISA. Results: Smoke and alcohol exposure alone elevated both AA and MDA, but only the combination of smoke + alcohol generated protein‐adducting concentrations of AA and MDA. MAA‐adducted protein (～500 ng/ml) was significantly elevated in the smoke + alcohol‐exposed mice. Of the 5 MAA‐adducted proteins identified by Western blot, 1 protein band immunoprecipitated with antibodies to surfactant protein D. Similar to in vitro PKC stimulation by purified MAA‐adducted protein, protein kinase C (PKC) epsilon was activated only in tracheal epithelial extracts from smoke‐ and alcohol‐exposed mice. Conclusions: These data demonstrate that only the combination of cigarette smoke exposure and alcohol feeding in mice results in the generation of significant AA and MDA concentrations, the formation of MAA‐adducted protein, and the activation of airway epithelial PKC epsilon in the lung.     

Cigarette smoke-induced acute airway impairment]

Cigarette smoking has been implicated in many pulmonary disorders, including chronic bronchitis and chronic obstructive lung disease. Cigarette smoking is associated with increased airway responsiveness. Acute exposure to cigarette smoke increases airway responsiveness in a dose-dependent manner. A superoxide is involved in airway hyper-responsiveness induced by cigarette smoke, perhaps by direct toxic action. Cigarette smokers have increased numbers of neutrophils present in their lower respiratory tract. Acute exposure to cigarette smoke initiates a superoxide-dependent mechanism that, through NF-kappa B activation and IL-8 expression, induces infiltration of neutrophils into the airways in vivo. The alveolar macrophage is one potential source of NF-kappa B activation and IL-8 production after acute exposure to cigarette smoke. Manipulation of NF-kappa B by antioxidants in vivo may be useful in limiting biologic processes such as pro-inflammatory cytokine production, which may lead to neutrophil accumulation in the lung.     

Effects of cigarette smoke exposure and cessation on inflammatory cells and matrix metalloproteinase activity in mice

B6C3F1 female mice were exposed to cigarette smoke (CS) (250 mg/m3 total particulate material) or filtered air (FA), 6 hours/day, 5 days/week, for 6, 7, or 10 weeks, or to CS for 6 weeks, then FA for 1 or 4 additional weeks. Exposure to CS increased macrophages, neutrophils, lymphocytes, and matrix metalloproteinase (MMP)-2 and MMP-9 content in bronchoalveolar lavage fluid. Partial recovery of most lavage parameters (except lymphocytes) was observed 1 week after cessation of CS exposure with further reductions after 4 weeks, but interstitial inflammation persisted longer. These results support a role for MMPs in CS-induced emphysema and indicate that smoking cessation allows restoration toward normal homeostasis.     

香烟烟雾暴露对支气管哮喘大鼠Th1／Th2细胞因子及转录因子GATA-3表达的影响

目的通过观察香炯烟雾暴露后支气管哮喘（简称哮喘）大鼠Th1／Th2细胞因子及转录因子GATA-3表达的变化,探讨吸烟加重哮喘的免疫学机制。方法48只雄性Wistar大鼠随机分为对照组、烟雾暴露组、哮喘组、哮喘＋烟雾暴露组;建立慢性哮喘大鼠模型和哮喘大鼠香炯炯雾暴露模型,普通病理观察气道壁厚度的变化,酶联免疫吸附试验检测外周血和肺组织γ干扰素（INF-γ）和白介素4（IL-4）含量;免疫印迹检测肺组织GATA-3蛋白表达水平。结果①哮喘＋烟雾暴露组气道壁厚度[（18．34±0．87）μm^2／μm]较哮喘组[（15．72±0．82）μm^2／μm]和对照组[（8．52±0．58）μm^2／μm]均明显增加,差异有统计学意义（P值均〈0．01）;②哮喘＋烟雾暴露组血浆和肺组织IL-4含量[（34．07±6．11）ng／L]、[（1．41±0．31）ng／L]较哮喘组[（22．57±4．32）ng／L]、[（0．80±0．14）ng／L]和对照组[（11．38±2．90）ng／L]、[（0．27±0．08）ng／L]均增高,差异有统计学意义（P值均〈0．05）;哮喘＋烟雾暴露组血浆INF-γ含量[（9．53±3．28）ng／L]较哮喘组[（58．83±19．57）ng／L]和对照组[（150．87±55．54）ng／L]均降低,差异有统计学意义（P值均〈0．05）,肺组织INF-γ含量[（0．48±0．10）ng／L]较哮喘组[（0．58±0．23）ng／L]差异无统计学意义;③哮喘＋烟雾暴露组GATA-3蛋白表达（1．29±0.08）较哮喘组（0．87±0．04）和对照组（0．45±0．06）均增加,差异有统计学意义（P值均〈0．01）。结论香烟烟雾暴露可以通过上调转录凶子GATA3蛋白表达,进而调控Th1／Th2偏移,在哮喘气道炎症及气道重塑的形成中扮演重要角色,为吸烟加重哮喘的免疫学机制之一。