Center for Primary Care and Public Health (Unisanté), Formerly IST, Institute for Work and Health, University of Lausanne, Lausanne, Epalinges, Switzerland.
Environmental Carcinogenesis Unit Ospedale Policlinico San Martino, Genoa, Italy.
Environ Res. 2020 Jan;180:108824. doi: 10.1016/j.envres.2019.108824. Epub 2019 Oct 12.
Micronuclei (MNs) are extranuclear DNA-containing bodies and determining MN frequencies is a measure of genomic instability. An age-related increase in MN frequencies in lymphocytes has been quantified, but this effect has not yet been measured in nasal and buccal cells.
We determined the effect of age on the MN frequency distributions in buccal and nasal cells among a sample of a general adult population in Switzerland. To maximize the power to detect an effect of age in our population study, we recruited preferentially younger and older working age adults. We harvested buccal and nasal cells from 32 young (19-36 year) and 33 working age (47-71 years) participants. The collected cells were washed, centrifuged, and stained (Feulgen) before microscopic manual counting in 2000 cells. Based on these results, we developed an age-dependent background MN frequency chart to help interpret an individual's MN frequency score as an early signal for the effect of genotoxic exposure.
MN frequencies were respectively 0.53‰ and 0.47‰ for buccal and nasal among the younger and 0.87‰ and 1.03‰ in the older working age group. This corresponded to a multiplicative slope of 14% and 20% per 10 years of age for buccal and nasal cells, respectively.
Based on our study results, we are able to propose an approach for interpreting an individual's MN screening results.
微核（MN）是含有额外核 DNA 的小体，测定 MN 频率可用于衡量基因组的不稳定性。已有研究对淋巴细胞中 MN 频率随年龄增长而增加的现象进行了量化，但尚未对鼻腔和口腔细胞中的这种现象进行测量。
我们对瑞士一个普通成年人群体样本中的口腔和鼻腔细胞中的 MN 频率分布随年龄的变化进行了研究。为了在我们的人群研究中最大程度地检测到年龄对 MN 频率的影响，我们主要招募了年轻和中年的成年工作者。我们从 32 名年轻（19-36 岁）和 33 名中年工作者（47-71 岁）中采集口腔和鼻腔细胞。收集的细胞经过清洗、离心和染色（Feulgen）后，在 2000 个细胞中进行显微镜手动计数。基于这些结果，我们开发了一个与年龄相关的背景 MN 频率图表，以帮助解释个体的 MN 频率评分，作为对遗传毒性暴露影响的早期信号。
年轻组的口腔和鼻腔 MN 频率分别为 0.53‰和 0.47‰，中年组的口腔和鼻腔 MN 频率分别为 0.87‰和 1.03‰。这相当于口腔和鼻腔细胞的年龄每增加 10 岁，MN 频率分别增加 14%和 20%。
基于我们的研究结果，我们能够提出一种解释个体 MN 筛查结果的方法。
