Investigation of Bronchiolitis Obliterans Caused by Artificial Butter flavoring

人造黄油调味品引起闭塞性细支气管炎的调查

• 批准号: 8929784
• 负责人: DANIEL MORGAN
• 金额: $ 55.46万
• 依托单位: NATIONAL INSTITUTE OF ENVIRONMENTAL HEALTH SCIENCES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8929784
• 关键词: Affect; Air; Animal Model; Biological; Breathing; Bronchi; Bronchiolitis; Bronchiolitis Obliterans; Butter; Chemicals; Chronic; Collagen Gene; Control Animal; Data; Development; Diacetyl; Disease; Distal; Dose; Down-Regulation; Early Diagnosis; Employee; Epithelial; Epithelium; Exposure to; Extracellular Matrix Proteins; Female; Fibrosis; Flavoring; Food Additives; Frozen Sections; Future; Gene Expression; Genes; Goals; Graft Rejection; Inflammatory; Inhalation Exposure; Investigation; Lasers; Lesion; Lung; Lung diseases; Methods; Microarray Analysis; Minor; Molecular; Occupational; Organ; Pathogenesis; Pathologic; Pathway interactions; Peptide Hydrolases; Plants; Prevention; Protease Inhibitor; RNA; Rattus; Relative (related person); Respiratory System; Respiratory tract structure; Rodent; Site; Survival Rate; Tissue-Specific Gene Expression; Tissues; Toxic effect; Transplantation; chemokine; consumer product; cytokine; diketone; effective therapy; insight; male; microwave electromagnetic radiation; therapeutic target

Diacetyl, a reactive diketone used in artificial butter flavoring has been associated with obliterative bronchiolitis (OB) in employees at microwave popcorn packaging plants; however, the mechanisms of toxicity are unknown. We recently demonstrated that diacetyl, the major volatile component of artificial butter flavoring, caused OB-like lesions in rats after inhalation exposure. Because of concerns about diacetyl toxicity, it is being replaced in some consumer products by 2,3-pentanedione (PD), and possibly 2,3-hexanedione (HD), both structurally-related and untested chemicals. Because the toxicity of inhaled PD and HD are unknown, studies were conducted to characterize the toxicity after inhalation exposure to a range of concentrations in rodents. Male and female Wistar-Han rats were exposed to 0, 50, 100, or 200 ppm PD 6h/d, 5d/wk for up to 2 wk. HD caused only minor epithelial changes at the highest concentration; however, PD was found to cause OB-like lesions similar to those caused by diacetyl. The epithelium lining the respiratory tract was the site of toxicity for all three chemicals. Diacetyl and PD both caused fibrotic airway lesions in rats with pathological features of OB. The pathological and biological changes observed in rats indicate that PD is not an acceptable replacement for diacetyl. We sought to evaluate changes in gene expression in the distal bronchi of rats with PD-induced OB. Male Wistar Han rats were exposed to 200 ppm PD or air (controls) 6 h/d, 5 d/week for 2-wks. Bronchial tissues were laser microdissected from serial sections of frozen lung. In exposed lungs, both fibrotic and non-fibrotic airways were collected. Following RNA extraction and microarray analysis, differential gene expression was evaluated. In non-fibrotic bronchi of exposed rats, 1548 genes were significantly altered relative to air-exposed controls with notable down-regulation of many inflammatory cytokines and chemokines. In contrast, in PD-exposed fibrotic bronchi, 2504 genes were significantly altered with a majority of genes being up-regulated in affected pathways. Tgf-beta2 and downstream genes implicated in fibrosis were significantly up-regulated in fibrotic lesions. Genes for collagens and extracellular matrix proteins were highly up-regulated. In addition, expression of genes for peptidases and for peptidase inhibitors were significantly altered suggesting tissue remodeling that may contribute to fibrosis. Additional control animals were evaluated by microarray to strengthen the statistical significance of gene changes in PD-exposed rats. Our data provide new insights into the molecular mechanisms of OB, and illustrate that PD-induced OB shares pathologic features with other fibrotic lung diseases. This new information is of potential significance with regards to future therapeutic targets for treatment.

二乙酰是一种用于人造黄油调味料的反应性二酮，它与微波爆米花包装厂员工的闭塞性细支气管炎 (OB) 有关；然而，毒性机制尚不清楚。我们最近证明，人造黄油调味剂的主要挥发性成分二乙酰在吸入后会引起大鼠 OB 样病变。由于担心二乙酰毒性，一些消费品中的二乙酰被 2,3-戊二酮 (PD) 和可能的 2,3-己二酮 (HD) 取代，这两种化学物质都是结构相关且未经测试的化学品。由于吸入 PD 和 HD 的毒性尚不清楚，因此进行了研究来表征啮齿动物吸入暴露于一定浓度后的毒性。雄性和雌性 Wistar-Han 大鼠暴露于 0、50、100 或 200 ppm PD 6 小时/天、5 天/周，持续长达 2 周。 HD 在最高浓度下仅引起轻微的上皮变化；然而，PD 被发现会引起类似于丁二酮引起的 OB 样病变。呼吸道内壁上皮是所有三种化学物质的毒性部位。双乙酰和PD均引起具有OB病理特征的大鼠气道纤维化病变。在大鼠中观察到的病理和生物学变化表明 PD 不是可接受的二乙酰替代品。 我们试图评估 PD 诱发的 OB 大鼠远端支气管中基因表达的变化。雄性 Wistar Han 大鼠暴露于 200 ppm PD 或空气（对照），每天 6 小时，每周 5 天，持续 2 周。从冷冻肺的连续切片中激光显微切割支气管组织。在暴露的肺部中，收集纤维化和非纤维化的气道。 RNA提取和微阵列分析后，评估差异基因表达。在暴露大鼠的非纤维化支气管中，与暴露于空气的对照组相比，1548 个基因发生显着改变，许多炎症细胞因子和趋化因子显着下调。相比之下，在PD暴露的纤维化支气管中，2504个基因发生显着改变，其中大多数基因在受影响的通路中上调。 Tgf-beta2 和与纤维化有关的下游基因在纤维化病变中显着上调。胶原蛋白和细胞外基质蛋白的基因高度上调。此外，肽酶和肽酶抑制剂的基因表达显着改变，表明组织重塑可能导致纤维化。通过微阵列评估其他对照动物，以加强 PD 暴露大鼠基因变化的统计显着性。 我们的数据为 OB 的分子机制提供了新的见解，并说明 PD 诱发的 OB 与其他纤维化肺疾病具有相同的病理特征。这一新信息对于未来的治疗目标具有潜在意义。