Effects of nitrous acid exposure on baseline pulmonary resistance and Muc5ac in rats

We examined the baseline pulmonary resistance (RLung), baseline dynamic lung compliance (Cdyn), cytokine inductions, and histological alterations in rats exposed to nitrous acid (HONO) with secondary products of nitrogen dioxide (NO₂) and nitric oxide (NO) to assess its biological effects. We exposed three groups of nine male F344 rats to different doses of HONO for six weeks (24?h/day). The cumulative values of HONO concentration were measured twice. The average concentrations of nitrogen oxide for each group were 5.8 parts per million (ppm) HONO with secondary products of 0.7?ppm NO₂ and 2.3?ppm NO, 4.1?ppm HONO with 0.1?ppm NO₂ and 0.6?ppm NO, and a clean air control. We measured baseline RLung and baseline Cdyn using tracheal cannulation. A tracheal tube was inserted into the trachea by tracheostomy, and lung function measurements (baseline RLung and baseline Cdyn) were conducted in mechanically ventilated rats. We measured mRNA levels of Cxcl-1, TNF-α, and Muc5ac in the right lung using quantitative RT-PCR, and observed histological alterations and the alveolar mean linear intercept (Lm) on the left lung. Our results demonstrated that HONO exposure significantly increased baseline RLung, Lm and Muc5ac expression, but did not affect baseline Cdyn or expression of Cxcl-1 and TNF-α. Further, we identified bronchial smooth muscle hypertrophy, pulmonary emphysema-like alterations in the alveolar duct centriacinar regions, and increased goblet cells in HONO-exposed rats. The present results suggest that HONO (with secondary products) adversely affects respiratory function, but that these pathologies may be unrelated to inflammation.     

Effects of inhaled aminophylline on airway constriction and inflammation in ovalbumin-sensitized guinea pigs

Abstract

Background: The systemic administration of theophylline is useful for asthma treatment. However its narrow therapeutic range makes it difficult to use. Little is known about its potential in inhalation therapy, particularly repeated inhalation.

Objective: The purpose of this study is to investigate the therapeutic usefulness of inhaled aminophylline in an asthma model.

Methods: The effects of pretreatment with inhaled aminophylline (25?mg/mL for 30?min/dose) on airway response and inflammation after an ovalbumin (OVA) challenge and airway hypersensitivity to acetylcholine (Ach) were evaluated using guinea pigs sensitized with OVA.

Results: Aminophylline relaxed the ACh-induced contraction of tracheal smooth muscle in vitro in a concentration-dependent manner. Pretreatment with single-dose aminophylline inhalation suppressed OVA-induced airway constriction to the same extent as the intraperitoneal pretreatment with high-dose aminophylline (10–20?mg/kg). However, pretreatment with single-dose aminophylline inhalation did not suppress eosinophil infiltration into airways (neither bronchoalveolar lavage [BAL] fluid nor lung tissue) and did not suppress airway hyperreactivity to ACh, 24?h after OVA challenge. Repeated inhalation of aminophylline (twice daily for 7 days) suppressed the infiltration of eosinophils and suppressed airway hypersensitivity to ACh. In addition, high concentrations of aminophylline inhibited production of oxygen radicals by BAL cells.

Conclusion: Single-dose inhalation treatment with aminophylline has transient but relatively strong bronchodilating effects due to delivery of high doses into local airways. Repeated inhalation treatment suppressed airway inflammation and hypersensitivity induced by allergens. Therefore, inhaled aminophylline may be useful for asthma treatment.     

α-萜品烯醇对豚鼠肺机械功能的影响

肺机械功能测定是整体动物实验中研究平喘药较好的方法。本文通过测定豚鼠的潮气量(V)、呼吸气流速度(F)和胸内压(P),描记压力—流速(P-F)曲线和压力—容量(P-V)曲线,计算肺阻力(R_L)和肺动态顺应性(Cdyn),研究艾叶油的有效平喘成分之一——α-萜品烯醇(α-Ter-pineol)对豚鼠气道的直接扩张作用,对豚鼠组胺引喘、卵白蛋白主动致敏和IgE抗血清被动致敏豚鼠实验性哮喘的保护作用,并且用心得安、利血平等工具药初步分析其作用机理,发现其作用并非通过兴奋β肾上腺素受体,亦不受肾上腺素能神经功能的影响。     

小剂量哌替啶对香烟烟雾致豚鼠急性肺气道反应的影响

目的研究小剂量阿片受体激动剂哌替啶(Peth)对香烟烟雾吸入引起的豚鼠急性气道收缩反应和炎性反应的影响。方法观察Peth0.01,0.1和1mg.kg-1对豚鼠自主吸入75%香烟烟雾(含25%O2)60mL后,气道阻力和肺动态顺应性变化的影响及气道组织血管通透性变化的影响;观察Peth0.1mg.kg-1对豚鼠2h内分6次吸入(共360mL)75%浓度的香烟烟雾后,支气管肺泡灌洗液(BALF)中白细胞总数和分类计数改变的影响,测定BALF中一氧化氮(NO)含量。结果Peth能减轻或明显抑制香烟烟雾刺激后气道阻力增高和肺动态顺应性下降的反应,抑制气道组织各段微血管通透性增加的反应,降低BALF中的白细胞总数和中性粒细胞比例,降低BALF中NO的含量。结论小剂量Peth对豚鼠急性神经源性气道收缩反应和炎性反应具有抑制作用。     

复方麻辛雾化液对哮喘豚鼠气道炎症机制的影响

目的:观察复方麻辛雾化液对哮喘豚鼠气道炎症的影响。方法:实验设正常对照组、模型对照组、复方麻辛组、沙丁胺醇组,选用豚鼠共80只,采用清蛋白造模,并运用巴氏染色法、放射免疫法、MIL型实验动物肺功能测量仪,分别检测肺泡灌洗液中嗜酸粒细胞(Eos)数、血浆凝血(?)烷(TXB_2)、6-酮-前列腺素(6-K-PGF_(1a))以及清蛋白激发后气道阻力(Ri、Re)和肺顺应性(Cor)。结果:与模型对照组比较,复方麻辛组Eos数目明显降低,6-K-PGF_(1a)含量显著升高,而TXB_2含量无显著差异;复方麻辛组经清蛋白激发后Ri、Re和Cor各值变化不显著,与正常对照组比较无显著差异,与沙丁胺醇组接近,模型对照组清蛋白激发后Ri、Re峰值明显升高,Cor较低,与上述2组比较有显著差异。结论:复方麻辛雾化液能显著抑制哮喘豚鼠的气道炎症反应,改善哮喘豚鼠的肺功能。     

兰尼碱受体mRNA在哮喘豚鼠气道平滑肌细胞中表达的改变

目的明确兰尼碱受体(RyR)与哮喘发病的关系,为哮喘的防治提供一条新的途径。方法以酶消化法分离培养正常与哮喘豚鼠气道平滑肌细胞(ASMCs),应用RT-PCR方法测定每组细胞RyR各亚型RyR1,RyR2和RyR3的mRNA表达。结果正常与哮喘豚鼠ASMCs中,RyR1和RyR2的mRNA均见表达,未见RyR3mRNA的表达,并以表达RyR2mRNA为主。哮喘时,RyR1和RyR2的mRNA相对吸光度值分别为0.43±0.05和1.5±0.6,明显高于正常组RyR1mRNA的吸光度值0.34±0.03(n=6,P<0.01)。结论RyR1mRNA表达上调可能与哮喘发病相关。     

Etanercept prevents airway hyperresponsiveness by protecting neuronal M2 muscarinic receptors in antigen-challenged guinea pigs

Background and purpose

Increased tumour necrosis factor-α (TNF-α) is associated with airway hyperreactivity in antigen-challenged animals. In human asthmatics, TNF-α is increased and blocking it prevents airway hyperreactivity in some asthmatic patients. However, the mechanisms by which TNF-α mediates hyperreactivity are unknown. Airway hyperreactivity can be caused by dysfunction of neuronal M₂ muscarinic receptors that normally limit acetylcholine release from parasympathetic nerves. Here we test whether blocking TNF-α receptors with etanercept prevents M₂ receptor dysfunction and airway hyperreactivity in antigen-challenged guinea pigs.

Experimental approach

Ovalbumin-sensitized guinea pigs were challenged by inhalation of antigen. Some animals received etanercept (3 mg kg⁻¹ i.p.) 3 h before challenge. 24 h after challenge, airway hyperreactivity and M₂ receptor function were tested. Inflammatory cells in bronchoalveolar lavage, blood and lung were counted. TNF-α and its receptors were detected by real-time RT-PCR and immunocytochemistry in parasympathetic nerves from humans and guinea pigs and in human neuroblastoma cells.

Key results

Antigen-challenged animals were hyperreactive to vagal stimulation and neuronal M₂ receptors were dysfunctional. Both M₂ receptor dysfunction and airway hyperreactivity were prevented by etanercept. Etanercept reduced eosinophils around airway nerves, and in blood, bronchoalveolar lavage and airway smooth muscle. Also, TNF-α decreased M₂ receptor mRNA in human and guinea pig parasympathetic neurons.

Conclusions and implications

Tumour necrosis factor-α may contribute to M₂ receptor dysfunction and airway hyperreactivity directly by decreasing receptor expression and indirectly by promoting recruitment of eosinophils, containing major basic protein, an M₂ antagonist. This suggests that etanercept may be beneficial in treatment of allergic asthma.     

Compensation of muscarinic bronchial effects of talsaclidine by concomitant sympathetic activation in guinea pigs

The aim of the present investigation was to determine the reasons why the muscarinic receptor agonist talsaclidine (WAL 2014 FU, 1-azabicyclo[2.2.2] octane,3-(2-propynyloxy)-, (R)-,(E)-2-butenedioate) is devoid of bronchospastic effects in anaesthetized guinea pigs but causes contracture in isolated tracheal muscle from this species. Effects on airway resistance were assessed with a modified Konzett–Rössler method in guinea pigs anaesthetized with urethane. Intravenous injection of 1–64 mg/kg talsaclidine did not cause substantial bronchospasm in control animals. After blockade of β-adrenoceptors, the muscarinic receptor agonist induced dose-dependent bronchospasm which could be blocked by atropine. In despinalized animals and in animals with spinal transection, talsaclidine was bronchospastic but ED₅₀ values were higher and maximal effects were smaller than in intact animals after β-adrenoceptor blockade. In adrenalectomized guinea pigs, talsaclidine was nearly as bronchospastic as after blockade of β-adrenoceptors. In contrast, the muscarinic ganglion stimulant McN-A-343, 4-(m-chlorophenylcarbamoyloxy)-2-butyn-trimethyl-ammonium chloride, (2–32 mg/kg i.v.), which has a muscarinic receptor profile similar to that of talsaclidine, i.e., full muscarinic agonism and highest affinity at muscarinic M₁ receptors, partial agonism at muscarinic M₃ receptors, but in contrast to talsaclidine does not penetrate the blood–brain barrier, caused dose-dependent bronchospasm in control animals. These results indicate that talsaclidine has bronchospastic potential which, however, does not become evident in vivo because of functional antagonism via β-adrenoceptors resulting from concomitant activation of the sympathetic nervous system in general and the adrenals in particular. It can be concluded that the unique profile of action of talsaclidine is due to partial agonism at bronchial muscarinic M₃ receptors, a prerequisite for susceptibility to functional antagonism, and to its ability to penetrate the blood–brain barrier readily and to induce sympathetic activation as a result of full agonism at peripheral ganglionic and adrenal as well as central muscarinic M₁ receptors.     

Effects of nitrous oxide on memory for instructions in dental patients

Outpatients attending for conservative dental treatment were presented with eight instructions which they were asked to remember. The instructions were either written or spoken, and were in a positive or negative form. Patients treated with nitrous oxide remembered fewer instructions than those treated with local analgesia alone, and this effect of nitrous oxide was particularly marked for written instructions. Patients receiving local analgesia alone were more likely to remember positive than negative instructions in their original syntactical form, but this bias was not evident in the nitrous oxide group. In a second experiment both normal and dentally phobic patients were read dental and general instructions both before and during inhalation of 30 per cent nitrous oxide. Both groups showed a nitrous oxide-induced reduction in partially recalled instructions. There was interesting evidence for a different attentional bias in our two patient groups. The normal group remembered more general than dental instructions, whereas the phobic group showed the opposite pattern, yielding a significant patient group × type of instruction interaction.     

沙丁胺醇抗豚鼠哮喘作用的昼夜节律

沙丁胺醇抗豚鼠哮喘作用的昼夜节律马孔琛，王敏，吴华彦（沈阳药科大学生理教研室，沈阳１１００１５）中国图书分类号Ｒ９７４．３提要沙丁胺醇扩张支气管平滑肌作用存在明显的昼夜节律。将动物置光—暗（１２ｈ光照）交迭的小室中饲养１ｗｋ后用于实验。在２４ｈ中的６...     

Effects of inhaled glaucine on pulmonary responses to antigen in sensitized guinea pigs

The alkaloid (S)-(+)-1,2,9,10-tetramethoxyaporphine (glaucine) is a phosphodiesterase 4 inhibitor with bronchodilator and anti-inflammatory activity in vitro. In this study, we examined the in vivo effects of glaucine on an animal model of asthma. In ovalbumin sensitized guinea pigs, inhaled glaucine (10 mg ml(-1), 3 min) inhibited the acute bronchoconstriction produced by aerosol antigen (antigen response was 256+/-42 and 95+/-14 cm H(2)O l(-1) s(-1) in control and glaucine-treated animals, respectively; P<0.05). Pretreatment with glaucine (10 mg ml(-1), 10 min inhalation, 30 min pre- and 3 h post-antigen exposure) markedly reduced airway hyperreactivity to histamine, eosinophil lung accumulation, and increased eosinophil peroxidase activity in bronchoalveolar lavage fluid 24 h after exposure of conscious guinea pigs to aerosol antigen. In addition, inhaled glaucine (5-10 mg ml(-1), 3 min) inhibited the microvascular leakage produced after inhaled antigen at all airway levels. These data support the potential interest of phosphodiesterase 4 inhibitors in asthma treatment.     

异丁司特对哮喘豚鼠气道嗜酸性粒细胞凋亡的作用及其机制

研究异丁司特 (ibudilast) 对哮喘豚鼠气道嗜酸性粒细胞 (eosinophil, EOS) 凋亡的作用及其机制。采用卵白蛋白致敏法制备豚鼠哮喘模型。收集支气管肺泡灌洗液 (BALF) 并进行白细胞计数及分类计数, TUNEL技术原位检测EOS凋亡, RT-PCR技术检测EOS的Fas mRNA表达, 酶联免疫吸附 (ELISA) 法测定BALF中粒细胞-巨噬细胞刺激因子 (GM-CSF) 及白介素-5 (IL-5) 的含量。结果表明, 异丁司特可明显减少哮喘豚鼠的白细胞总数和EOS数目; 在异丁司特剂量组, EOS凋亡细胞明显增多, Fas mRNA的表达显著增强, BALF中GM-CSF、IL-5含量显著降低, 与模型组比较有显著性差异。因此, 异丁司特抑制哮喘豚鼠气道EOS数目的增加、诱导EOS凋亡、增强Fas mRNA的表达、降低GM-CSF、IL-5含量可能是其拮抗哮喘的重要机制。     

孟鲁司特对哮喘豚鼠气道嗜酸性粒细胞凋亡及Fas mRNA表达的影响

目的研究白三烯受体拮抗剂孟鲁司特(montelukast,MK)对哮喘豚鼠气道嗜酸性粒细胞(eosinophil,Eos)凋亡和Fas mRNA表达的影响。方法以卵白蛋白致敏豚鼠制备哮喘模型。用密度梯度离心法分离并计数支气管肺泡灌洗液(BALF)中的嗜酸性粒细胞；采用TUNEL技术原位检测嗜酸性粒细胞凋亡；通过逆转录-多聚酶链反应(RT-PCR)技术检测嗜酸性粒细胞Fas mRNA的表达。结果孟鲁司特能显著降低哮喘豚鼠BALF中Eos的数量；在孟鲁司特治疗组，嗜酸性粒细胞凋亡指数明显升高，Fas mRNA的表达显著增强，与模型组比较均有显著性差异。结论嗜酸性粒细胞凋亡与Fas mRNA表达增加高度相关；增强气道嗜酸性粒细胞Fas mRNA的表达，促进其凋亡，可能是孟鲁司特拮抗哮喘气道炎症的一个重要机制。     

班布特罗对豚鼠实验性哮喘的作用及其机理研究

目的 研究班布特罗对豚鼠实验性哮喘的作用、药效学及药动学特点及作用机制。方法 组胺和卵清蛋白诱发在体豚鼠实验性哮喘模型,使用豚鼠离体气管片和肺条进行研究。结果 班布特罗剂量依赖性抑制组胺和卵清蛋白诱发的豚鼠哮喘,班布特罗对豚鼠气管片无松弛作用,而灌服其后的松弛气管片和肺条血浆呈剂量依赖性,且对肺条的松弛作用强于气管片。其峰效应出现于给药后4h前后,作用持续24h以上。结论 班布特罗作为特布他林的前药对豚鼠实验性哮喘的作用缓和而持久。     

雌二醇对豚鼠哮喘的影响及其与β受体的关系

豚鼠分4组;Ⅰ.去势+E_2400μg;Ⅱ.去势+E_z50Oμg;Ⅲ.保留卵巢+茶油;Ⅳ.去势+茶油。卵白蛋白(Ova)ip致敏,14 d后吸入Ova攻击诱发哮喘,共10 d,致敏同时开始皮下注射E_2,发现第Ⅰ、Ⅱ、Ⅲ组Ova引喘潜伏期较Ⅳ组缩短,Iso对His引喘的保护作用减弱、RLBA法发现第Ⅰ组肺脏β受体Rt值较第Ⅳ组降低,K_d值不变,推测E_2加强哮喘的作用与β受体功能降低和数目减少有关.     

全反式维甲酸对肺气肿模型大鼠的干预作用

目的研究不同时间段给予全反式维甲酸(ATRA)对肺气肿模型大鼠的干预作用及其机制。方法60只SD大鼠随机分为6组:生理盐水组(N组)、模型组(P组)、棉籽油组(C组)、早期干预组(R1组)、中期干预组(R2组)和后期干预组(R3组),每组10只。N组大鼠气管滴注生理盐水1mL·kg-1,其余5组气管滴注5%木瓜蛋白酶1mL·kg-1建立肺气肿模型。R1、R2和R3组分别于造模后15～30d、30～45d和45～60d给予ATRA500μg·kg-1腹腔注射,C组给予棉籽油腹腔注射。观察各组支气管肺泡灌洗液(BALF)中血管内皮生长因子(VEGF)含量和细胞数,肺组织病理学改变及肺组织血管内皮生长因子受体2(VEGFR-2)、基质金属蛋白酶1(MMP-1)的表达水平。结果与N组比较,P组BALF中细胞总数明显升高(P<0.01),其中以巨噬细胞和中性粒细胞为主。R1、R2和R3组与P组比较细胞总数降低(P<0.01),此3组之间无显著差异。与N组比较,其余5组平均肺泡面积和内衬间隔增大,每个视野内肺泡数减少(P<0.01);与P组相比,R1、R2和R3组肺泡数增加、平均肺泡面积减小(P<0.01),以R1组最为明显。与N组相比,P组VEGF和VEGFR-2表达降低,MMP-1表达增高(P<0.01);与P组相比,R1、R2和R3组VEGF和VEGFR-2表达增高,MMP-1表达降低(P<0.05),R1、R2和R3组之间无显著差异。结论ATRA可以促进肺泡再生,早期干预效果较佳,这种作用可能与调节VEGF、VEGFR-2、MMP-1有关。     

粉尘螨滴剂对豚鼠特异性哮喘反应的脱敏作用

目的建立粉尘螨提取蛋白诱导的豚鼠哮喘模型，观察粉尘螨滴剂的脱敏作用。方法粉尘螨蛋白致敏豚鼠在抗原静脉注射攻击后测定气道阻力和肺动态顺应性；甲酰胆碱气雾吸入激发气道高反应性，计数和分类支气管肺泡灌洗液中的炎症细胞，观察肺组织病理学的改变。治疗组用粉尘螨滴剂舌下给药治疗，模型组滴入等量的生理盐水，正常对照组不作任何处理。结果模型组豚鼠经抗原攻击后气道阻力明显增加，肺动态顺应性明显降低；甲酰胆碱气雾吸入能激发气道高反应性；嗜酸性粒细胞浸润明显增加。粉尘螨滴剂治疗组与模型组比较，哮喘反应明显改善。结论粉尘螨滴剂长期舌下给药对豚鼠哮喘反应有明显的脱敏作用，为临床治疗提供了实验依据。     

Mast cell mediators in citric acid-induced airway constriction of guinea pigs

We demonstrated previously that mast cells play an important role in citric acid (CA)-induced airway constriction. In this study, we further investigated the underlying mediator(s) for this type of airway constriction. At first, to examine effects caused by blocking agents, 67 young Hartley guinea pigs were divided into 7 groups: saline + CA; methysergide (serotonin receptor antagonist) + CA; MK-886 (leukotriene synthesis inhibitor) + CA; mepyramine (histamine H1 receptor antagonist) + CA; indomethacin (cyclooxygenase inhibitor) + CA; cromolyn sodium (mast cell stabilizer) + CA; and compound 48/80 (mast cell degranulating agent) + CA. Then, we tested whether leukotriene C4 (LTC4) or histamine enhances CA-induced airway constriction in compound 48/80-pretreated guinea pigs. We measured dynamic respiratory compliance (Crs) and forced expiratory volume in 0.1 s (FEV0.1) during either baseline or recovery period. In addition, we detected histamine level, an index of pulmonary mast cell degranulation, in bronchoalveolar lavage (BAL) samples. Citric acid aerosol inhalation caused decreases in Crs and FEV0.1, indicating airway constriction in the control group. This airway constriction was significantly attenuated by MK-886, mepyramine, cromolyn sodium, and compound 48/80, but not by either methysergide or indomethacin. Both LTC4 and histamine infusion significantly increased the magnitude of CA-induced airway constriction in compound 48/80-pretreated guinea pigs. Citric acid inhalation caused significant increase in histamine level in the BAL sample, which was significantly suppressed by compound 48/80. These results suggest that leukotrienes and histamine originating from mast cells play an important role in CA inhalation-induced noncholinergic airway constriction.     

秦氏循经敷贴对实验性哮喘豚鼠的作用

目的：探讨中药秦氏循经敷贴对哮喘豚鼠的作用。方法：30只健康豚鼠随机分为空白对照组（A组）、哮喘模型组（B组）和秦氏循经敷贴组（C组）,每组10只。以鸡卵蛋白攻击致敏。C组敷贴秦氏循经敷贴;B组敷贴含生理盐水的医用纱布。于末次敷药后检测豚鼠外周血嗜酸性粒细胞百分比、中性粒细胞百分比和白细胞总数,肺组织和支气管HE染色后观察病理改变。结果：与A组相比,B组外周血嗜酸性粒细胞百分比显著升高（P〈0.05）,C组较B组显著降低（P〈0.05）;中性粒细胞百分比和白细胞总数3组间无显著性差异（P〉0.05）。B组肺组织大量炎症细胞浸润,部分肺泡腔阻塞、实变,肺泡间隔明显增宽,支气管管壁血管扩张、管壁增厚;C组炎症细胞浸润较少,肺泡充气,无间隔增宽;A组炎症细胞浸润程度较轻,无支气管壁增厚。结论：秦氏循经敷贴能改善实验性哮喘豚鼠的肺及支气管的炎症反应,减少外周血嗜酸性粒细胞百分比,对哮喘豚鼠具有治疗作用。