Chronic obstructive pulmonary disease (COPD) in humans, describes a group of lung conditions characterised by airflow limitation that is poorly reversible. The airflow limitation usually progresses slowly and is related to an abnormal inflammatory response of the lung to toxic particles. COPD is characterised by oxidative stress and an increased risk of lung carcinoma. The 2-amino-3-methylimidazo [4,5-f]quinoline (IQ) is one of a number of mutagenic/carcinogenic heterocyclic amines found mainly in well-cooked meats which are thus part of the regular diet. Antioxidants are very important in order to protect the cells against oxidative damage. The aim of the present study was to assess the effects of IQ on the level of DNA damage and susceptibility to a potent mutagen in peripheral blood cells of COPD patients. DNA damage and the frequency of micronuclei (MNi) were evaluated using the Comet and micronucleus assays, respectively. Differential expressions of both mRNA and protein of the endogenous antioxidant enzyme catalase were evaluated with quantitative polymerase chain reaction (qPCR) and Western blot analysis, respectively. Furthermore, the effect of bulk and nano forms of quercetin and their combination with IQ were examined. Results of the present study clearly demonstrated that MNi frequency in the peripheral blood lymphocytes exhibited a positive correlation with the DNA damage as evident from the different Comet assay parameters. Increase of the endogenous antioxidant catalase also showed there was a stimulation of this enzyme system by IQ. Whereas, the endogenous antioxidant quercetin significantly reduced oxidative stress in COPD patients and healthy individuals.

人类的慢性阻塞性肺疾病（COPD）描述了一组以难以逆转的气流受限为特征的肺部疾病。气流受限通常进展缓慢，并且与肺部对有毒颗粒的异常炎症反应有关。COPD的特征是氧化应激和肺癌风险增加。2-氨基-3-甲基咪唑并[4,5-f]喹啉（IQ）是许多诱变/致癌杂环胺之一，主要存在于煮熟的肉中，因此是常规饮食的一部分。为了保护细胞免受氧化损伤，抗氧化剂非常重要。本研究的目的是评估IQ对COPD患者外周血细胞DNA损伤水平和对强致突变剂敏感性的影响。分别使用彗星和微核试验评估DNA损伤和微核（MNi）频率。内源性抗氧化酶过氧化氢酶的mRNA和蛋白的差异表达分别通过定量聚合酶链反应（qPCR）和蛋白质印迹分析进行评估。此外，还研究了槲皮素的块状和纳米形式及其与IQ的组合的作用。本研究结果清楚地表明，外周血淋巴细胞中的MNi频率与DNA损伤呈正相关，从不同的Comet分析参数可以明显看出。内源性抗氧化剂过氧化氢酶的增加还表明，IQ刺激了该酶系统。然而，