Nicotine causes genotoxic damage but is not metabolized during long-term exposure of human nasal miniorgan cultures
Nicotine causes genotoxic damage but is not metabolized during long-term exposure of human nasal miniorgan cultures
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DOI：
10.1016/j.toxlet.2014.06.842
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发表时间：
2014-08-17
影响因子：
3.5
通讯作者：
Kleinsasser, Norbert H.
中科院分区：
文献类型：
--
作者：
Ginzkey, Christian;Steussloff, Gudrun;Kleinsasser, Norbert H.
人鼻小器官培养物（MOC）是生态遗传毒理学研究的有用工具。重复暴露于尼古丁显示出可逆的DNA损伤，并且在先前的研究中证明了鼻MOC中的稳定CYP 2A 6表达。本研究的目的是评估尼古丁在慢性尼古丁暴露后鼻MOC中的遗传毒性效应，并监测可能的代谢能力。MOC从人鼻粘膜解剖并在标准细胞培养条件下培养。MOC以1 μ M和1 mM的浓度暴露于尼古丁3周。根据重度吸烟者的尼古丁血浆水平以及尼古丁鼻喷雾剂局部应用中使用的可能浓度选择浓度。在第7、14和21天通过彗星试验评估DNA损伤。通过气相色谱/质谱法分析细胞培养基中尼古丁和可替宁的浓度，以确定尼古丁可能通过MOC代谢。暴露于1 μ M和1 mM尼古丁1周后，MOC中的DNA损伤明显。这种效应在2周和3周后降低，没有统计学相关的DNA迁移。通过上清液中尼古丁和可替宁浓度的变化，未检测到尼古丁代谢。这是第一次在慢性尼古丁暴露长达3周后评价鼻MOC的遗传毒性效应。培养1周后出现遗传毒性效应，并随时间推移而降低。鼻粘膜中表达的烟碱乙酰胆碱受体的下调可能是一种可能的解释。该模型中尼古丁代谢的缺乏可以通过慢性尼古丁暴露期间CYP 2A 6的功能丧失来解释。有必要进行进一步的研究，以更详细地描述尼古丁对DNA损伤的潜在机制。(C)2014爱思唯尔爱尔兰有限公司版权所有。
Human nasal miniorgan cultures (MOC) are a useful tool in ecogenotoxicology. Repetitive exposure to nicotine showed reversible DNA damage, and stable CYP2A6 expression was demonstrated in nasal MOC in previous investigations. The aim of the present study was to evaluate the genotoxic effect of nicotine in nasal MOC after chronic nicotine exposure, and to monitor possible metabolism capacities. MOC were dissected from human nasal mucosa and cultured under standard cell culture conditions. MOC were exposed to nicotine for 3 weeks at concentrations of 1 mu M and 1 mM. The concentrations were chosen based on nicotine plasma levels in heavy smokers, and possible concentrations used in topical application of nicotine nasal spray. DNA damage was assessed by the comet assay at days 7, 14 and 21. Concentrations of nicotine and cotinine were analyzed in cell culture medium by gas chromatography/mass spectrometry to determine a possible metabolism of nicotine by MOC. Distinct DNA damage in MOC could be demonstrated after 1 week of exposure to 1 mu M and 1 mM nicotine. This effect decreased after 2 and 3 weeks with no statistically relevant DNA migration. No nicotine metabolism could be detected by changes in nicotine and cotinine concentrations in the supernatants. This is the first time genotoxic effects have been evaluated in nasal MOC after chronic nicotine exposure for up to 3 weeks. Genotoxic effects were present after 1 week of culture with a decrease over time. Down-regulation of nicotinic acetylcholine receptors, which are expressed in nasal mucosa, may be a possible explanation. The lack of nicotine metabolism in this model could be explained by the functional loss of CYP2A6 during chronic nicotine exposure. Further investigations are necessary to provide a more detailed description of the underlying mechanisms involved in DNA damage by nicotine. (C) 2014 Elsevier Ireland Ltd. All rights reserved.