Exhaled breath (EB) contains various volatile organic compounds (VOCs) that can indicate specific biological or pathological processes in the body. Analytical techniques like gas chromatography/mass spectrometry (GC/MS) can be used to detect and measure these exhaled biomarkers. In this study, the objective was to develop a non-invasive method of EB sampling in awake animals, as well as to analyze EB for volatile biomarkers specific for chlorine exposure and/or diagnostic biomarkers for chlorine-induced acute lung injury (ALI). To achieve this, a custom-made sampling device was used to collect EB samples from 19 female Balb/c mice. EB was sampled both pre-exposure (serving as internal control) and 30-min after exposure to chlorine. EB was collected on thermal desorption tubes and subsequently analyzed for VOCs by GC/MS. The following day, the extent of airway injury was assessed in the animals by examining neutrophils in the bronchoalveolar lavage fluid. VOC analysis revealed alterations in the EB biomarker pattern post-chlorine exposure, with eight biomarkers displaying increased levels and six exhibiting decreased levels following exposure. Four chlorinated compounds: trichloromethane, chloroacetone, 1,1-dichloroacetone, and dichloroacetonitrile, were increased in chlorine-exposed mice, suggesting their specificity as chlorine EB biomarkers. Furthermore, chlorine-exposed mice displayed a neutrophilic inflammatory response and body weight loss 24h following exposure. In conclusion, all animals developed an airway inflammation characterized by neutrophil infiltration and a specific EB pattern that could be extracted after chlorine exposure. Monitoring EB samples can readily and non-invasively provide valuable information on biomarkers for diagnosis of chlorine-induced ALI as well as confirming chlorine exposures.

中文翻译：

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在接触氯的小鼠中发现潜在的呼出气生物标志物

呼出气（EB）含有各种挥发性有机化合物（VOC），可以指示体内特定的生物或病理过程。气相色谱/质谱 (GC/MS) 等分析技术可用于检测和测量这些呼出的生物标志物。在本研究中，目的是开发一种在清醒动物中进行 EB 采样的非侵入性方法，并分析 EB 中氯暴露特异性挥发性生物标志物和/或氯引起的急性肺损伤 (ALI) 的诊断生物标志物。为了实现这一目标，使用了定制的采样装置从 19 只雌性 Balb/c 小鼠中采集 EB 样本。在暴露前（作为内部对照）和暴露于氯后 30 分钟对 EB 进行取样。在热解吸管上收集 EB，随后通过 GC/MS 分析 VOC。第二天，通过检查支气管肺泡灌洗液中的中性粒细胞来评估动物气道损伤的程度。 VOC 分析揭示了暴露于氯后 EB 生物标志物模式的变化，其中 8 种生物标志物在暴露后表现出水平升高，而 6 种生物标志物表现出水平下降。四种氯化化合物：三氯甲烷、氯丙酮、1,1-二氯丙酮和二氯乙腈在接触氯的小鼠中含量增加，表明它们作为氯 EB 生物标志物的特异性。此外，暴露于氯的小鼠在暴露后 24 小时表现出中性粒细胞炎症反应和体重减轻。总之，所有动物都出现了以中性粒细胞浸润为特征的气道炎症，以及在氯暴露后可以提取的特定 EB 模式。监测 EB 样本可以轻松且非侵入性地提供有关生物标志物的宝贵信息，用于诊断氯诱发的 ALI 以及确认氯暴露。