Regelmann W E, Schneider L A, Fahrenkrug S C, Gray B H, Johnson S, Herron J M, Clawson C C, Clawson D J, Wangensteen O D
Department of Pediatrics, University of Minnesota, Minneapolis, USA.
Pediatr Pulmonol. 1997 Jul;24(1):29-34. doi: 10.1002/(sici)1099-0496(199707)24:1<29::aid-ppul5>3.0.co;2-e.
In cystic fibrosis the bronchiectatic conducting airways have large numbers of neutrophils in their walls and in their luminal contents. The neutrophil's primary granule enzyme activities of elastase and peroxidase are increased in the sputum of these patients. It has been postulated that these enzymes--together or individually--act to damage the airway epithelium. However, only peroxidase activity has consistently correlated with the degree of structural and functional airway disease in these patients with leakage of plasma protein into the airway lumen (Regelmann et al., Pediatr Pulmonol, 1995; 19:1-9). The present study was designed to test whether human neutrophil-derived myeloperoxidase can independently produce bronchial epithelial damage without the presence of proteases, as measured by increased permeability of the airway epithelium. Human peripheral blood neutrophils were purified, their primary granules isolated, and their peroxidase purified using affinity and ion exchange column chromatography. Activity of the proteinase-free peroxidase was measured using a chromogenic substrate. The effect of this peroxidase on the permeability of excised rat tracheas was measured using radioactive and fluorescent-labeled non-ionic molecules of varying molecular weight. Rat tracheas exposed to 15 minute treatments with either 130 U of peroxidase or hydrogen peroxide (10(-5) M) did not show a significant increase in the permeability of the epithelium to [3H]inulin, [14C]sucrose, and fluorescein isothiocyanate dextran 20 compared with control tracheas. However, those tracheas exposed to 130 U peroxidase followed by 10(-5) M hydrogen peroxide showed an increased permeability to each of the three test solutes. We conclude that proteinase-free myeloperoxidase, in the presence of non-toxic concentrations of its substrates, hydrogen peroxide and halide, produced increases in permeability to non-ionic molecules in the rat trachea within 15 minutes.
在囊性纤维化中，支气管扩张的传导气道壁及其管腔内含有大量中性粒细胞。这些患者痰液中中性粒细胞的主要颗粒酶（弹性蛋白酶和过氧化物酶）活性增加。据推测，这些酶共同或单独作用会损伤气道上皮。然而，只有过氧化物酶活性一直与这些血浆蛋白漏入气道腔的患者气道结构和功能疾病的程度相关（Regelmann等人，《儿科肺病学》，1995年；19:1 - 9）。本研究旨在测试人中性粒细胞衍生的髓过氧化物酶在不存在蛋白酶的情况下是否能独立导致支气管上皮损伤，通过气道上皮通透性增加来衡量。纯化人外周血中性粒细胞，分离其主要颗粒，并使用亲和和离子交换柱色谱法纯化其过氧化物酶。使用显色底物测量无蛋白酶过氧化物酶的活性。使用不同分子量的放射性和荧光标记非离子分子测量该过氧化物酶对离体大鼠气管通透性的影响。与对照气管相比，用130 U过氧化物酶或过氧化氢（10⁻⁵ M）处理15分钟的大鼠气管，其上皮对[³H]菊粉、[¹⁴C]蔗糖和异硫氰酸荧光素葡聚糖20的通透性没有显著增加。然而，那些先暴露于130 U过氧化物酶然后再暴露于10⁻⁵ M过氧化氢的气管，对三种测试溶质中的每一种的通透性都增加了。我们得出结论，在其底物过氧化氢和卤化物的无毒浓度存在下，无蛋白酶的髓过氧化物酶在15分钟内使大鼠气管对非离子分子的通透性增加。
