SO2-induced enhancement of inhalative allergic sensitization: inhibition by anti-inflammatory treatment.

Epidemiological studies have shown a relationship between air pollution and allergic airway disease. In a previous study we have found that exposure to SO2 enhances allergic sensitization to inhaled ovalbumin (OA) in the guinea pig. We have now investigated the influence of pre-treatment with anti-inflammatory drugs on SO2-induced enhancement of allergic sensitization in this model. Four groups of 6 guinea pigs each were exposed to 5 ppm SO2 on 5 consecutive days over 8 h per day with intermittent inhalation of OA, while the air-control group was exposed to clean air and OA. During the period of SO2 exposure and sensitization three experimental groups were treated with indomethacin (group I), methylprednisolone (group M) and nebulized nedocromil sodium (group N), while the control group remained untreated. Guinea pigs were investigated for sensitization to OA by specific bronchial provocation tests using body plethysmographic measurement of compressed air (CA) and by measurement of specific antibody response in serum. While in the SO2-exposed control group 5 of 6 animals reacted to specific bronchial provocation testing (CA median 0.15 ml, range 0-0.175 ml), only 1 animal was sensitized in group M (CA 0 ml, 0-0.125, p < 0.05), whereas no bronchial reactions were seen in groups I and N (CA 0 ml, 0-0.05, p < 0.025). Specific IgG antibody titres increased in the control group (median 43 EU-->85 EU), but not in the treatment groups (medians group I 35 EU-->35 EU, group M 30-->35 EU, group N 64-->50 EU).(ABSTRACT TRUNCATED AT 250 WORDS)     

Inhibition of antigen-induced late asthmatic response and bronchial hyperresponsiveness by cyclosporin A

We have previously demonstrated that Cyclosporin A (CyA), a T lymphocyte-selective immunosuppressive agent, reduced the delayed-phase bronchial eosinophil infiltration after antigen challenge in a guinea pig model of asthma. In the present study, we studied the effects of CyA on antigen-induced late asthmatic response (LAR) and bronchial hyperresponsiveness following LAR. Guinea pigs immunized by repeated exposure to aerosolized ovalbumin (OA) were intravenously given metopirone, a cortisol synthesis inhibitor, 24 hours before and 30 minutes 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 was significantly increased. However, when guinea pigs were treated with CyA from the beginning of immunization period, the development of LAR was completely inhibited, although similar magnitude of immediate bronchoconstriction was observed, and a subsequent increase in bronchial responsiveness was partially but significantly blocked. Since CyA has been shown to suppress activation of guinea pig T lymphocytes and their production of lymphokines, these results suggest that T cell factor(s) may be important for the elicitation of LAR and the antigen-induced bronchial hyperresponsiveness.     

Inhibitory effect of FK-506 on the development of late asthmatic response and on the increased bronchial responsiveness]

We examined the effects of FK-506, a potent immunosuppressive agent, on the development of late asthmatic response (LAR) and on the increased bronchial responsiveness to acetylcholine following LAR in guinea pig model of asthma. Guinea pigs sensitized by repeated inhalation of ovalbumin (OA) were intravenously given metopiron 24 hours before and 30 minutes before antigen challenge and to prevent death from immediate severe bronchoconstriction, chlorpheniramine maleate was also injected. When we defined LAR as the responses with a two-fold increase in respiratory resistance during the late phase of antigen challenge, twelve out of fifteen control animals demonstrated apparent LAR. However, when guinea pigs were treated with FK-506 from the beginning of immunization period, the development of LAR was completely inhibited, although similar magnitude of immediate bronchoconstriction was observed, and a subsequent increase in bronchial responsiveness was significantly blocked. We also measured bronchial responsiveness to acetylcholine before, 24 and 72 hours after antigen challenge. FK-506-treated animals inhibited an increase in bronchial responsiveness to acetylcholine. These results suggest that the involvement of cell-mediated immunity may be important in the development of LAR and an increase in bronchial responsiveness.     

The mechanism of airway hyperresponsiveness following immediate bronchial response in ovalbumin (OA)-sensitized guinea pigs]

We have previously demonstrated that airway responsiveness was enhanced following a late bronchial response (LBR) after an allergen challenge in ovalbumin (OA)-sensitized guinea pigs. The purpose of the present studies was to evaluate whether airway responsiveness to methacholine increased after an immediate bronchial response (IBR) and the possible involvement of the beta-adrenoceptor dysfunction in OA-sensitized guinea pigs. Guinea pigs were actively sensitized by aerosolized OA. Following OA exposure, IBR appeared. After IBR when specific airway resistance returned to the base line value, airway responsiveness to methacholine increased significantly. Before OA exposure, propranolol induced bronchoconstriction (PIB) was not provoked, however, after IBR, PIB was provoked and the guinea pigs died because of severe bronchoconstriction. These results suggest that airway responsiveness to methacholine increases significantly after IBR. Furthermore, the dysfunction of the beta-adrenoceptor may be a mechanism of this hyperresponsiveness in OA-sensitized guinea pigs.     

哮喘支气管黏膜中类胰蛋白酶的表达增强

目的 观察含类胰蛋白酶的肥大细胞在豚鼠支气管黏膜的表达和分布特征。方法 Dunkin Hartley豚鼠随机分为哮喘组(A组)和生理盐水组(B组)。用100m/mL卵蛋白进行致敏，并于致敏后第5周行抗原特异性支气管激发试验。激发后2h取各组豚鼠支气管组织标本，免疫组化染色以抗人类胰蛋白酶(Tryptase)单克隆抗体(AAl)为一抗，过氧化物酶标记的绵羊抗鼠IgG为二抗，并用联苯二胺(Diaminobenzidine，DAB)显色。仅选择阳性染色细胞进行计数。结果 鼠抗人Trvptase单克隆抗体即可识别人支气管Tryptase又可识别豚鼠支气管Tryptase。哮喘支气管组织中Tryptase阳性细胞数明显多于正常支气管组织。相似地，支气管激发试验后的豚鼠支气管组织中的肥大细胞数要比生理盐水吸入组多出2．0倍以上。结论 抗人Tryptase单克隆抗体可以用于识别豚鼠支气管的肥大细胞。哮喘者和激发试验阳性的豚鼠支气管肺组织中的Tryptase阳性肥大细胞数明显多于正常支气管组织，表明肥大细胞在支气管哮喘发病机制中可能起重要作用。     

卡介苗对豚鼠实验性哮喘的预防性治疗作用

目的:观察卡介苗(BCG)对哮喘豚鼠的预防治疗作用。方法:采用31只豚鼠,分为3组进行处理,分别为对照组、卵蛋白(OVA)致敏组和BCG处理组。用OVA(Ⅲ级)致敏豚鼠复制豚鼠哮喘模型。结果:本模型采用10%的OVA致敏,1%的OVA激发,所有动物都表现有不同程度的过敏反应症状。实验动物在接受BCG注射后,表现为以下特点:一是外周血淋巴细胞和单核细胞增加;二是BALF中细胞分类的变化,支气管肺泡灌洗液(BALF)中以淋巴细胞的增加最为明显。 经过OVA致敏的动物BALF和肺组织中嗜酸性粒细胞(EOS)明显增加,BCG不同程度地降低肺组织EOS的气道浸润及减轻OVA致敏豚鼠的气道反应。结论:[HTSS]使用本实验体系BCG可以减轻实验性哮喘的气道炎症反应。     

Formaldehyde exposure enhances inhalative allergic sensitization in the guinea pig

Formaldehyde (FA), a common indoor air pollutant, has been associated with increased prevalence rates of asthmatic symptoms among exposed individuals in epidemiologic surveys. We studied the influence of FA exposure on inhalative allergic sensitization in the guinea pig. Three groups of guinea pigs ( n = 12 each) were exposed to clean air or two different FA concentrations (0.13 and 0.25 ppm) over 5 consecutive days. Exposure was followed by inhalation of 0.5% ovalbumin (OA) as sensitizing allergen. Three weeks later, specific bronchial provocation with OA was performed with body plethysmographic measurement of compressed air (CA). Furthermore, specific anti-OA-IgG1 (reaginic) antibodies were determined in serum. In a further six animals, the respiratory tract was examined histologically for signs of inflammation directly after the end of FA or clean air exposure. In the group exposed to 0.25 ppm FA, 10/12 animals were found to be sensitized to OA (positive reaction on specific provocation) vs. 3/12 animals in the control group ( P < 0.01). Furthermore, CA measurements of specific bronchial provocation and serum anti-OA-antibodies were significantly higher in the 0.25 ppm FA group than in controls (CA 0.35 vs. 0.09 ml median, P < 0.01; anti-OA-IgG1 13 vs. < 10 EU median, P < 0.05), indicating enhanced sensitization. In the group exposed to 0.13 ppm FA, no significant difference was found compared to the control group. There was no sign of inflammation of the lower airways in FA-exposed guinea pigs other than mucosal edema, which was discovered by morphometry. We conclude that short-term exposure to a low concentration of FA (0.25 ppm) can significantly enhance sensitization to inhaled allergens in the guinea pig.     

Involvement of platelet activating factor (PAF) in ovalbumin antigen-induced late asthmatic response and increase of airway hyperresponsiveness in a guinea pig experimental model of asthma

Platelet activating factor, a potent chemical mediator, has been implicated in the pathogenesis of asthma in terms of inflammatory cell recruitment and activation. We have recently demonstrated that repeated antigen (ovalbumin; OA) exposure by inhalation to guinea pigs results in a development of late asthmatic response (LAR) in more than 50% of the animals and significant increase in airway hyperresponsiveness (AH). We have studied the effect of WEB 2086, a specific PAF receptor-antagonist, on this model. Respiratoly resistance (Res) of guinea pigs was measured by a oscillation technique and AH was evaluated by the provocative concentration of aerosols of histamine causing 200% increase of Rrs over the baseline Rrs (PC200 Hist). Four out of 5 actively sensitized and diphenhydramine-pretreated animals developed LAR 3 to 9 hr after allergen (20 mg/ml OA, 10 min inhalation)-induced immediate bronchoconstriction (LAR). Treatment with WEB 2086 (3 mg/kg intravenously) 30 min before and 3 hr after the exposure suppressed LAR clearly without affecting the IAR. Significant increase in AH from 2.80 +/- 0.03 to 2.51 +/- 0.01 and 2.60 +/- 0.08 (p less than 0.05, n = 8) of PC200 Hist (mg/ml, log) was observed 24 hr and 5 day after the OA exposure, respectively. The WEB 2086 treatment also prevented the increase of AH after the OA exposure (PC200 Hist; 2.82 +/- 0.09 before the challenge 2.80 +/- 0.07 and 2.75 +/- 0.09 24 hr and 5 days after, respectively. n = 8). Administration of WEB 2086 did not affect baseline Rrs and PC200 Hist in normal guinea pigs without any antigen challenge. We conclude that WEB 2086 is capable of preventing the development of LAR and increase in AH, and thus PAF may play an important causal role in LAR and increased AH observed in asthma.     

Effects of leukotriene B4 receptor antagonist, LY293111Na, on antigen-induced bronchial hyperresponsiveness and leukocyte infiltration in sensitized guinea pigs

OBJECTIVE AND DESIGN: LY29311 Na, 2-[2-propyl-3-[3-[2-ethyl-4-(4-fluorophenyl)-5-hydroxyphenoxy] propoxy] -phenoxy]-benzoic acid sodium salt, is a novel leukotriene B4 (LTB4) receptor antagonist. Its effects on guinea pig models of asthma were compared with those of dexamethasone. METHODS: Effects of LY293111Na were tested in antigen (ovalbumin, OA)-induced bronchial hyperresponsiveness (BHR) and leukocyte accumulation in actively sensitized guinea pigs. Its effects on antigen-induced acute bronchoconstriction in passively sensitized guinea pigs were also studied. RESULTS: LY293111 Na (10 to 30 mg/kg p.o., 1 h before and 6 h after OA challenge) inhibited BHR to acetylcholine. LY293111 Na (3 mg/kg p. o.) significantly inhibited accumulation of neutrophils in bronchoalveolar lavage (BAL) fluid 24 h after antigen challenge but it did not inhibit accumulation of eosinophils and macrophages at any doses used. In contrast, dexamethasone (30 mg/kg p.o., 4 h before OA challenge) not only inhibited BHR but also reduced the infiltration of all three types of leukocytes. A significant increase of LTB4 levels in BAL fluid was noted at 3 and 15 min after the antigen challenge. LY293111Na did not inhibit antigen-induced acute bronchoconstriction in passively sensitized guinea pigs. CONCLUSION: These results indicate that LTB4 may participate in antigen-induced BHR but not in eosinophil infiltration and acute bronchoconstriction in guinea pigs.     

支气管哮喘豚鼠BALF炎症细胞中PPARγ、Nrf2和γ-GCS-h表达的变化

目的:研究支气管哮喘急性发作豚鼠肺泡灌洗液(BALF)炎症细胞中PPARγ、Nrf2和γ-GCS-h表达变化并探索PPARγ对Nrf2/γ-GCS-h作用。方法:40只健康雄性豚鼠随机化原则分成对照组(A组)、哮喘组(B组)、地塞米松组(C组)和罗格列酮组(D组),每组10只豚鼠,卵蛋白致敏法复制哮喘模型。收集BALF,行细胞计数和分类,离心,上清液行活性氧(ROS)和丙二醛(MDA)浓度测定,细胞涂片原位杂交检测PPARγ、Nrf2和γ-GCS-hmRNA表达,细胞涂片免疫细胞化学检测PPARγ、Nrf2和γ-GCS-h蛋白表达。结果:B组嗜酸性粒细胞数(EOS)比例高于A组、C组和D组,差异显著(P0.01),BALF中ROS和MDA浓度在B组中最高,4组间差异显著(均P0.05);PPARγ、Nrf2和γ-GCS-hmRNA和蛋白在B组表达最低,4组表达差异显著(均P0.01)。PPARγ与Nrf2/γ-GCS-h表达均呈正相关(均P0.05);γ-GCS-h与Nrf2表达呈正相关(r=0.954,P0.05);哮喘组PPARγ、γ-GCS-h和Nrf2表达均与浸润的嗜酸性粒细胞数呈负相关(均P0.05)。结论:PPARγ和Nrf2/γ-GCS-h在卵蛋白致敏急性支气管哮喘模型BALF炎症细胞中表达均下降;PPARγ可上调Nrf2/γ-GCS-h表达,在抑制炎症反应和氧化应激中发挥重要作用,这可能为支气管哮喘防治开辟新途径。     

Bronchoprotective effects of atrial natriuretic peptide against propranolol-induced bronchoconstriction after allergic reaction in guinea pigs

OBJECTIVE: To study the effects of intravenous atrial natriuretic peptide (ANP) on antigen-induced bronchoconstriction, propranolol-induced bronchoconstriction (PIB) after antigen challenge, and histamine-induced bronchoconstriction in guinea pigs. METHODS: Allergic bronchoconstriction was evoked by inhalation of ovalbumin (OA) and PIB was caused when 10 mg/mL of propranolol was inhaled 20 min after OA challenge in passively sensitized and artificially ventilated guinea pigs. 25, 50, 100 and 200 microg/mL of histamine were inhaled for 20 s at 5-min intervals in non-sensitized guinea pigs. RESULTS: Pretreatment with ANP in doses of 0.1 and 1.0 nmol/kg injected intravenously 15 min after antigen challenge reduced PIB in a dose-dependent manner, and 5 min before antigen challenge significantly attenuated PIB but not antigen-induced bronchoconstriction. Intravenous ANP significantly reduced bronchial responses to increasing concentrations of inhaled histamine in a dose-dependent manner. CONCLUSION: These results suggest that ANP possesses protective effects against propranolol-induced and histamine-induced bronchoconstriction, albeit by a non-specific mechanism in guinea pig in vivo.     

微卡对哮喘豚鼠肺组织嗜酸粒细胞凋亡及Bcl-2蛋白表达的影响

目的：研究微卡对哮喘豚鼠肺组织嗜酸粒细胞凋亡及Bcl-2蛋白表达的影响。 方法： 30只豚鼠随机分为生理盐水组、哮喘组及微卡组，每组10只。微卡组每只豚鼠在OVA致敏前10 d肌注22.5 μg微卡。应用TUNEL法检测肺组织嗜酸粒细胞的凋亡，免疫组化法检测肺组织Bcl-2蛋白的表达。 结果： 微卡组豚鼠肺组织嗜酸粒细胞凋亡指数（23.78±5.42）%显著高于哮喘组（4.56±0.68）%(P<0.01)；肺组织Bcl-2蛋白平均积分吸光度值（1 556.3±492.4）显著低于哮喘组（2 321.9±751.2）（P<0.05）。 结论： 微卡能诱导哮喘豚鼠肺组织嗜酸粒细胞凋亡，可能与其抑制Bcl-2蛋白在哮喘豚鼠肺组织的表达有关。     

Human and guinea pig immune responses to Legionella pneumophila protein antigens OmpS and Hsp60.

We studied the immune responses of guinea pigs and humans to two Legionella pneumophila antigens. Guinea pigs surviving a lethal intraperitoneal challenge dose of virulent L. pneumophila exhibited strong cutaneous delayed-type hypersensitivity (DTH) reactions to purified OmpS (28-kDa major outer membrane protein) and Hsp60 (heat shock protein or common antigen), while weak DTH reactions were noted for extracellular protease (major secretory protein [MSP] [ProA]) and no reaction was observed with an ovalbumin (OA) control. Lymphocyte proliferation responses (LPRs) were measured for peripheral blood and spleen lymphocytes from guinea pigs surviving sublethal and lethal challenge doses of L. pneumophila. Lymphocytes from uninfected animals showed no proliferation to Hsp60 or OmpS, while lymphocytes from sublethally and lethally challenged animals exhibited strong proliferative responses to Hsp60 and OmpS. Guinea pigs vaccinated with purified OmpS exhibited low antibody titers and strong DTH and LPRs to OmpS, whereas lymphocytes from animals vaccinated with Hsp60 exhibited weak DTH responses and high antibody titers to Hsp60. All guinea pigs immunized with OmpS survived experimental challenge with L. pneumophila (two of two in a pilot study and seven of seven in trial 2) versus zero of seven OA-immunized controls (P = 0.006 by Fisher's exact test). In three vaccine trials in which animals were vaccinated with Hsp60, only 1 guinea pig of 15 survived lethal challenge. Peripheral blood lymphocytes (PBLs) from humans with legionellosis showed stronger LPRs to OmpS than PBLs from humans with no history of legionellosis (P = 0.0002 by Mann-Whitney test). PBLs of humans surviving legionellosis exhibited a lower but highly significant proliferative response to Hsp60 (P < 0.0001 compared with controls by Mann-Whitney test). These studies indicate that OmpS and Hsp60 are important antigens associated with the development of protective cellular immunity. However, as determined in vaccine trial studies in the guinea pig model for legionellosis, the species-specific antigen OmpS proved much more effective than the genus-common Hsp60 antigen.     

Neurokinin-1 receptor antagonist inhibits short-term sulfuric-acid-induced airway hyperresponsiveness in sensitized guinea pigs

BACKGROUND: Tachykinins are involved in the development of bronchial inflammation and airway hyperresponsiveness (AHR); however, the role of the neurokinin-1 (NK(1)) receptor in acid-aerosol-induced bronchial impairment in asthmatic patients remains controversial. METHODS: To investigate the effects on the NK(1) receptor antagonist FK888 the neurokinin-2 (NK(2)) receptor antagonist SR48968 on sulfuric-acid (H(2)SO(4))-induced AHR in guinea pigs, specific airways resistance (sRaw) and airways responsiveness to methacholine (MCh) were measured before and after 6 h of exposure to H(2)SO(4) aerosol (pH 1.7, 82 mg/m(3)) in ovalbumin-sensitized guinea pigs. RESULTS: Airway responsiveness to MCh significantly increased (p<0. 05) after the exposure, however sRaw did not. Treatment with FK888 significantly inhibited (p<0.05) H(2)SO(4)-induced AHR in a dose-dependent manner, as did SR48968. CONCLUSIONS: These results suggest that not only NK(2) but also NK(1) receptors might have important roles in the development of acid-aerosol-induced AHR.     

低压低氧治疗对哮喘豚鼠的影响

目的:探讨模拟高原防治哮喘的机理。方法:用卵蛋白致敏和诱发复制哮喘动物模型,分为哮喘发作组、缓解组和低压舱治疗组,并设立正常对照组进行以下检测:①放免法测定血浆及支气管灌洗液(BALF)中内皮素(ET)含量及血浆皮质醇水平;②肺组织切片光镜检查。结果:①光镜下哮喘发作组肺组织切片见嗜酸性粒细胞(EOS)浸润明显,缓解组浸润较少,治疗组明显减少;②血浆皮质醇水平发作组、缓解组分别明显高于和低于正常组,治疗组与正常组无明显差异;血浆ET含量哮喘缓解组明显高于其他3组,而BALF中ET含量则为发作组明显高于其他3组,后3组之间无明显差异。结论:低压低氧治疗后,哮喘豚鼠血浆及BALF中内皮素降低而血浆中皮质醇增高,肺组织嗜酸性粒细胞浸润减少,这可能是模拟高原环境防治哮喘的机理之一。     

哮喘豚鼠嗜酸细胞Bcl-2和Bax mRNA表达及意义

目的:观察Bcl-2及Bax mRNA表达与嗜酸粒细胞（Eos）凋亡的关系,探讨其在哮喘发病中的作用。方法:健康豚鼠随机分为正常组、哮喘组,卵蛋白致敏激发制作哮喘模型,检测支气管灌洗液（BALF）中低密度EoS（HEos）及正常密度Eos（NEos）细胞凋亡,原位杂交及RT-PCR法检测Bcl-2及Bax mRNA表达。结果:哮喘组EoS显著高于正常组,以HEos为著（P<0.01）;Eos凋亡率明显低于正常组（P<0.01）。哮喘组不同密度Eos表达Bcl-2 mRNA明显增加,而Eos表达Bax mRNA明显减少。结论:哮喘时Eos存在凋亡抑制,这是哮喘时Eos增多的原因之一,哮喘豚鼠BALF Eos表达Bcl-2增加,表达Bax减少,表明Bcl-2及Bax可通过调节Eos凋亡参与哮喘发病。     

地塞米松对哮喘豚鼠肺及内脏感觉传入系统神经生长因子表达的抑制作用

目的：探讨地塞米松对哮喘豚鼠肺及内脏感觉传人系统(C7-T5脊神经节及对应的脊髓后角)神经生长因子(NGF)表达的影响。方法：利用免疫组织化学和Westem印迹方法,观察生理盐水组、单纯致敏组、哮喘组和地塞米松组豚鼠肺及内脏感觉传人系统(C7-T5脊神经节及对应的脊髓后角)NGF表达的变化。结果：哮喘组豚鼠NGF在肺及内脏感觉传人系统(C7-T5脊神经节及对应的脊髓后角)表达明显高于对照组,而地塞米松组则明显低于哮喘组。结论：NGF可能参与哮喘的发病过程,地塞米松抑制哮喘豚鼠NGF的表达可能是其治疗哮喘的机制之一。     

Effects of Ding-Chuan-Tang on Bronchoconstriction and Airway Leucocyte Infiltration in Sensitized Guinea Pigs

Ding-Chuan-Tang (DCT), a traditional Chinese medicine, has been used in treatment of the bronchial asthma for several centuries. However, the therapeutic mechanism of these Chinese medicine are still far from clear. To understand the mechanism of antiasthmatic property of DCT. A guinea pig model of allergic asthma was used to investigate the effects of DCT on ovalbumin-induced early and late asthmatic responses and airway inflammation, particularly the extent of eosinophil infiltration, and examine it direct β2-adrenoceptor agonist activity in guinea-pig isolated trachea. We had used three different protocals in ovalbumin sensitized guinea pigs by administrating 10 g/kg of DCT extracts to sensitized guinea pigs 30 min before antigen challenge (group I), 5 hr after antigen challenge (group II) and 2.5 g/kg once daily from the day of sensitization to the day of challenge. Our result showed that administration of DCT singificantly inhibited the antigen induced immediate asthmatic responses (IAR) in group I and inhibited both IRA and late asthmatic responses (LAR) in actively sensitized guinea pig in group III. DCT caused concentration-dependent relaxations in strips of guinea pig trachea contracted with carbachol, however ICI-118551, a selective β2-adrenoceptor antagonist, didn't significantly competitively inhibit the relaxations caused by DCT. Furthermore, examination of bronchoalveolar lavage fluid (BALF) revealed that DCT significantly inhibited the increase in percent of eosinophils in the airway after antigen challenge in three group. Histopathologic examination showed DCT suppressed the eosinophil infiltration into lung tissue. These results suggest that the antiasthmatic effect of DCT is mainly due to its bronchodilatation effect and its ability to inhibit the eosinophil into the airway and there is prophylactic effect of DCT on allergen-induced airway inflammation.     

黄芪对豚鼠哮喘模型血红素氧合酶—1表达的影响

用免疫组织化学染色方法观察血红素氧合酶-1（HO-1）在哮喘豚鼠肺组织中的表达变化，测定全血一氧化碳血红蛋白（COHb)的百分比含量并观察气道壁嗜酸性粒细胞（EOS）浸润情况，以探讨黄芪对哮喘豚鼠HO-1表达的影响。发现HO-1主要表达在气道上皮细胞，哮喘各组HO-1的表达水平均显著高于正常组（P＜0.01)。黄芪治疗后HO-1的表达水平显著低于哮喘各组（P＜0.01)。可见黄芪能显著抑制哮喘豚鼠气道上皮细胞HO-1的表达，提示黄芪抑制细胞HO-1的表达可能是黄芪治疗哮喘的作用机制之一。     

Effects of Ding-Chuan-Tang on bronchoconstriction and airway leucocyte infiltration in sensitized guinea pigs

Ding-Chuan-Tang (DCT), a traditional Chinese medicine, has been used in treatment of the bronchial asthma for several centuries. However, the therapeutic mechanism of these Chinese medicine are still far from clear. To understand the mechanism of antiasthmatic property of DCT. A guinea pig model of allergic asthma was used to investigate the effects of DCT on ovalbumin-induced early and late asthmatic responses and airway inflammation, particularly the extent of eosinophil infiltration, and examine it direct beta2-adrenoceptor agonist activity in guinea-pig isolated trachea. We had used three different protocals in ovalbumin sensitized guinea pigs by administrating 10 g/kg of DCT extracts to sensitized guinea pigs 30 min before antigen challenge (group I), 5 hr after antigen challenge (group II) and 2.5 g/kg once daily from the day of sensitization to the day of challenge. Our result showed that administration of DCT singificantly inhibited the antigen induced immediate asthmatic responses (IAR) in group I and inhibited both IRA and late asthmatic responses (LAR) in actively sensitized guinea pig in group III. DCT caused concentration-dependent relaxations in strips of guinea pig trachea contracted with carbachol, however ICI-118551, a selective beta2-adrenoceptor antagonist, didn't significantly competitively inhibit the relaxations caused by DCT. Furthermore, examination of bronchoalveolar lavage fluid (BALF) revealed that DCT significantly inhibited the increase in percent of eosinophils in the airway after antigen challenge in three group. Histopathologic examination showed DCT suppressed the eosinophil infiltration into lung tissue. These results suggest that the antiasthmatic effect of DCT is mainly due to its bronchodilatation effect and its ability to inhibit the eosinophil into the airway and there is prophylactic effect of DCT on allergen-induced airway inflammation.