Monitoring histological changes in oral mucosa using AgNORs as biomarkers for oxygenic stress in smokers and COPD patients

Background: It is well known that tobacco smoke causes cellular proliferation and chronic obstructive pulmonary disease (COPD), but changes in buccal mucosa cells in smokers and COPD patients remains unknown. Aims: The aim of this study is twofold: (i) to assess the effect of smoking on cellular proliferative activity of buccal mucosa in healthy smokers and in smoking COPD patients (ii) to detect early cellular proliferative activity in buccal mucosa. Our hypothesis is that tobacco smoking induces changes in buccal mucosa cells that we can detect using AgNOR analysis. Methods:879 male subjects; non-smokers (controls), smokers and COPD patients were studied. Cytogenic damage was defined using the argyrophilic nucleolar organiser regions (AgNOR). Buccal mucosa cells were obtained from swabs and brushing. The respiratory symptoms were assessed by St. George’s questionnaire and lung function tests were measured by Vitalograph spirometer. Statistical analysis using ANOVA and discriminant analysis (classification) was used to determine differences between the three groups, regression models were built on the lung function data. Results:The AgNOR count, nuclear area, nuclear volume, and percentage of cells with 5 or more AgNORs, were significantly higher in smokers than non–smokers (5.20 vs 3.27, 74.66 vs 55.65, 462.67 vs 304.01, 73.93% vs 14.75%, respectively). For COPD patients, the values were 6.77, 110.42, 813.26, 96.97%, respectively. Respiratory symptoms were higher in smokers and COPD patients than non-smokers. There was significant relationship between respiratory symptoms and AgNORs count (P≤ 0.001). There was positive association between cigarette smoking and enhanced cellular activity in oral mucosa. Pack years of smoking is significantly associated with cellular abnormality in smokers and COPD patients. Conclusions: Strong correlations were found between AgNORs parameters and respiratory symptoms, pulmonary function tests and pack years.