Impact of cigarette smoking on genetic stability, cell division, and cytotoxicity in buccal cells of old and young women

We investigated the impact of cigarette smoking, daily exposure to tar and nicotine, and the duration of smoking on genetic instability (chromosomal damage-micronuclei, MN, nuclear buds-gene amplification) as well as on disturbances in mitosis (resulting in binucleated cells). Furthermore, we analyzed markers of cytotoxic effects (such as the formation of condensed chromatin, pyknotic, karyolytic, and karyorrhectic cells) and the mitotic activity of the oral mucosa. These parameters were monitored in groups of old (postmenopausal) and young (premenopausal) smoking and nonsmoking women (n = 25/group). We found no differences in the MN frequencies in the non-smoking groups and only a moderate (not significant) increase of MN in both groups of smokers. However, we observed a clear increase in markers of genomic instability in both smoking groups. Furthermore, the mitotic activity of cells in the mucosa and of anomalies caused by acute cytotoxicity was higher in both smoking groups. Nicotine uptake was associated with pronounced acute toxic effects and increased cell division rate. Chromosomal damage (MN) was higher in individuals who consumed high amounts of tar (this effect was not significant) and caused moderate acute toxicity. Our findings indicate (i) that age and hormonal status have no strong impact on the genotoxic and cytotoxic effects in smoking women, (ii) consumption of up to 30 cigarettes/day does not cause chromosomal damage in buccal cells, however, positive results were found in earlier studies in heavy smokers, (iii) smoking increased markers which reflect genetic instability and the division rate of oral mucosa cells. These effects may play a role in the neoplastic transformation of cells in the upper respiratory tract in smokers. The duration of smoking was associated with a slight (not significant) increase in the mitotic activity and of chromosomal damage and with moderate acute cytotoxicity.