BACKGROUND Workers in the zinc production and processing of galvanized sheet steel are exposed to a complex mixture of particles and gases, including zinc oxide (ZnO) that can affect human health. We aimed to study the effects of short-term controlled exposure to nano-sized ZnO on airway inflammatory markers in healthy volunteers. METHODS Sixteen subjects (8 females, 8 men; age 19-42, non-smokers) were exposed to filtered air and ZnO nanoparticles (0.5, 1.0 and 2.0 mg/m3) for 4 h, including 2 h of cycling with a low workload. Induced sputum samples were collected during a medical baseline and a final examination and also about 24 h after each exposure. A number of inflammatory cellular and soluble markers were analyzed. RESULTS Frequency and intensity of symptoms of airway irritation (throat irritation and cough) were increased in some subjects 24 h after ZnO exposures when compared to filtered air. The group comparison between filtered air and ZnO exposures showed statistically significant increases of neutrophils and interleukin-8 (IL-8), interleukin-6 (IL-6), matrix metalloproteinase (MMP-9) and tissue inhibitors of metalloproteinases (TIMP-1) in sputum starting at the lowest ZnO concentration of 0.5 mg/m3. However, a concentration-response relationship was absent. Effects were reversible. Strong correlations were found between neutrophil numbers and concentrations of total protein, IL-8, MMP-9, and TIMP-1. CONCLUSIONS Controlled exposures of healthy subjects to ZnO nanoparticles induce reversible airway inflammation which was observed at a concentration of 0.5 mg/m3 and higher. The lack of a concentration-response relationship warrants further studies.

中文翻译：

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吸入人体志愿者中的纳米级氧化锌颗粒后气道发炎。

背景技术镀锌钢板的锌生产和加工中的工人暴露于颗粒和气体的复杂混合物中，包括会影响人体健康的氧化锌（ZnO）。我们旨在研究健康志愿者中纳米氧化锌的短期控制暴露对呼吸道炎症标记物的影响。方法16名受试者（8名女性，8名男性； 19-42岁，不吸烟）暴露于过滤空气和ZnO纳米颗粒（0.5、1.0和2.0 mg / m3）中4小时，包括2小时低负荷骑车。在医学基线和最终检查期间以及每次暴露后约24小时内收集诱导的痰标本。分析了许多炎性细胞和可溶性标志物。结果与过滤后的空气相比，接触ZnO 24小时后某些受试者的气道刺激症状（咽喉刺激和咳嗽）的频率和强度增加。过滤后的空气和ZnO暴露之间的组比较显示，嗜中性粒细胞和白细胞介素8（IL-8），白细胞介素6（IL-6），基质金属蛋白酶（MMP-9）和金属蛋白酶组织抑制剂（TIMP-1）在统计学上显着增加痰液中的ZnO最低浓度为0.5 mg / m3。但是，没有浓度-反应关系。效果是可逆的。发现中性粒细胞数量与总蛋白，IL-8，MMP-9和TIMP-1的浓度之间存在很强的相关性。结论控制健康受试者暴露于ZnO纳米颗粒会引起可逆的气道炎症，其浓度为0.5 mg / m3或更高。缺乏集中反应关系值得进一步研究。