The effect of human eosinophil granule major basic protein on airway responsiveness in the rat in vivo. A comparison with polycations.
The effect of human eosinophil granule major basic protein on airway responsiveness in the rat in vivo. A comparison with polycations.
复制标题
人嗜酸性粒细胞颗粒主要碱性蛋白对大鼠体内气道反应性的影响。
DOI：
10.1164/ajrccm/147.4.982
复制
发表时间：
1993
期刊：
影响因子：
--
通讯作者：
Irvin,CG
中科院分区：
文献类型：
--
作者：
Uchida,DA;Ackerman,SJ;Coyle,AJ;Larsen,GL;Weller,PF;Freed,J;Irvin,CG
主要碱性蛋白（MBP）是一种在嗜酸性粒细胞颗粒中发现的高度阳离子蛋白。有推测认为，MBP可能参与哮喘患者气道高反应性的发病机制。因此，我们使用大鼠模型来研究人MBP滴注对气道反应性的影响以及阳离子电荷在确定这种影响中的可能作用。在基线时测定吸入乙酰甲胆碱（MDRC）的剂量反应特征，并允许动物恢复。然后实验组中的动物通过直接滴注到气管中接受100 μ g纯化的人MBP。滴注后1小时，再次评估MDRC。对照动物接受来自用于纯化MBP的相同色谱柱的空隙体积池的缓冲液（代替MBP）。在滴注MBP后1小时，气道对吸入乙酰甲胆碱的反应性显著增加，而对照动物没有表现出气道反应性的增加。MBP组的一些动物在MBP滴注后48小时重新研究，此时气道反应性已恢复至基线水平。还检查了聚阳离子聚-L-精氨酸和聚-L-赖氨酸对气道反应性的影响。与MBp一样，在滴注任一聚阳离子后1小时，气道对吸入乙酰甲胆碱的反应性增加。此外，聚-L-赖氨酸上的带电基团的乙酰化导致这种效果的丧失。组织学检查的气道未能揭示气道上皮脱落后1小时MBP或聚阳离子滴注。我们的结论是：（1）气道滴注MBP导致气道反应性的短暂增加，（2）MBP表面高密度的阳离子电荷可能是这种效应的原因，（3）气道上皮脱落不是这种效应的必要先决条件。气道对非特异性刺激（如吸入组胺和乙酰甲胆碱）的反应性增加是哮喘的一个重要特征（1）。虽然这种高反应性发展的机制在很大程度上仍然未知，但嗜酸性粒细胞被认为有助于这一过程（2）。嗜酸性粒细胞颗粒的主要碱性蛋白（MBP）在哮喘患者的气道中含量增加（3，4），对死于哮喘的患者的免疫荧光研究表明MBP沉积在气道上皮损伤部位（5）。MBP是一种富含精氨酸的高度阳离子蛋白，pi为10.9（6）。MBP可通过直接作用于平滑肌、改变上皮功能（7-9）和/或损伤气道上皮（10，11）对气道功能产生影响。豚鼠气管环体外暴露于人MBP引起反应性增加
Major basic protein (MBP) is a highly cationic protein found in the granules of eosinophils. It has been postulated that MBP may participate in the pathogenesis of airway hyperresponsiveness exhibited by asthmatic patients. Accordingly, we used a rat model to investigate the effect of human MBP instillation on airway responsiveness and the possible role of cationic charge in the determination of this effect. Doseresponse characteristics to inhaled methacholine (MDRC) were determined at baseline, and the animals were allowed to recover. Then animals in the experimental group received 100 Jlg of purified human MBP via direct instillation into the trachea. One hour after instillation, the MDRC were again assessed. Control animals received (in lieu of MBP) buffer from the void volume pool of the same chromatography column used to purify the MBP One hour after instillation of MBP there was a significant increase in airway responsiveness to inhaled methacholine, whereas control animals exhibited no increase in airway responsiveness. Some animals from the MBP group were restudied 48 h after MBP instillation, by which time airway responsiveness had returned to baseline level. The effect of the polycations poly-L-arginine and pOly-L-lysine on airway responsiveness was also examined. As with MBp, airway responsiveness to inhaled methacholine increased 1 h after the instillation of either polycation. In addition, acetylation of the charged groups on poly-L-Iysine resulted in a loss of this effect. Histologic examination of the airways failed to reveal airway epithelial shedding 1 h after MBP or polycation instillation. We conclude (1) that airway instillation of MBP results in a short-lived increase in airway responsiveness,(2) that the high density of surface cationic charge present on MBP may be responsible for this effect, and (3) that airway epithelial shedding is not a necessary prerequisite for this effect.An increase in airway responsiveness to nonspecific stimuli such as inhaled histamine and methacholine is an important feature of asthma (1). Although the mechanisms underlying the development of this hyperresponsiveness are still largely unknown, eosinophils are thought to contribute to this process (2). Major basic protein (MBP) of eosinophil granules is present in increased amounts in the sputa of asthmatics (3, 4), and immunofluorescence studies in patients who succumbed to asthma have shown MBP to be deposited at sites of airway epithelial damage (5). MBP is an arginine-rich, highly cationic protein with a pi of 10.9 (6). MBP could have an effect on airway function by a direct effect on smooth muscle, by altering epithelial function (7-9), and/or by damaging the airway epithelium (10, 11)./n vitro exposure of guinea pig tracheal rings to human MBP causes an increase in responsiveness