Witzenrath Martin, Ahrens Birgit, Kube Stefanie M, Braun Armin, Hoymann Heinz G, Hocke Andreas C, Rosseau Simone, Suttorp Norbert, Hamelmann Eckard, Schütte Hartwig
Department of Internal Medicine/Infectious Diseases, Charité, University Medicine Berlin, Germany.
Am J Physiol Lung Cell Mol Physiol. 2006 Sep;291(3):L466-72. doi: 10.1152/ajplung.00011.2005. Epub 2006 Apr 14.
Airway hyperresponsiveness (AHR) is a hallmark of bronchial asthma. Important features of this exaggerated response to bronchoconstrictive stimuli have mostly been investigated in vivo in intact animals or in vitro in isolated tracheal or bronchial tissues. Both approaches have important advantages but also certain limitations. Therefore, the aim of our study was to develop an ex vivo model of isolated lungs from sensitized mice for the investigation of airway responsiveness (AR). BALB/c mice were sensitized by intraperitoneal ovalbumin (Ova) and subsequently challenged by Ova inhalation. In vivo AR was measured in unrestrained animals by whole body plethysmography after stimulation with aerosolized methacholine (MCh) with determination of enhanced pause (P(enh)). Twenty-four hours after each P(enh) measurement, airway resistance was continuously registered in isolated, perfused, and ventilated lungs on stimulation with inhaled or intravascular MCh or nebulized Ova. In a subset of experiments, in vivo AR was additionally measured in orotracheally intubated, spontaneously breathing mice 24 h after P(enh) measurement, and lungs were isolated further 24 h later. Isolated lungs of allergen-sensitized and -challenged mice showed increased AR after MCh inhalation or infusion as well as after specific provocation with aerosolized allergen. AR was increased on days 2 and 5 after Ova challenge and had returned to baseline on day 9. AHR in isolated lungs after aerosolized or intravascular MCh strongly correlated with in vivo AR. Pretreatment of isolated lungs with the beta(2)-agonist fenoterol diminished AR. In conclusion, this model provides new opportunities to investigate mechanisms of AHR as well as pharmacological interventions on an intact organ level.
气道高反应性（AHR）是支气管哮喘的一个标志。这种对支气管收缩刺激的过度反应的重要特征大多已在完整动物体内或离体气管或支气管组织中进行了体外研究。这两种方法都有重要优点，但也有一定局限性。因此，我们研究的目的是建立一种来自致敏小鼠的离体肺的体外模型，用于研究气道反应性（AR）。通过腹腔注射卵清蛋白（Ova）使BALB/c小鼠致敏，随后通过吸入Ova进行激发。在用雾化乙酰甲胆碱（MCh）刺激后，通过全身体积描记法在不受约束的动物中测量体内AR，并测定增强暂停（P（enh））。在每次P（enh）测量后24小时，在用吸入或血管内MCh或雾化Ova刺激时，连续记录离体、灌注和通气肺中的气道阻力。在一组实验中，在P（enh）测量后24小时，还在经口气管插管、自主呼吸的小鼠中测量体内AR，24小时后进一步分离肺。致敏和激发的小鼠的离体肺在吸入或输注MCh后以及在用雾化变应原进行特异性激发后显示AR增加。在Ova激发后第2天和第5天AR增加，并在第9天恢复到基线。雾化或血管内MCh后离体肺中的AHR与体内AR密切相关。用β2激动剂非诺特罗预处理离体肺可降低AR。总之，该模型为在完整器官水平上研究AHR机制以及药物干预提供了新的机会。
