RESUMEN
Introduction and Aim: Cigarette smoking causes severe health problems such as cancer. Micronuclei are structures that present after genomic damages to the cells. The present study is aimed at evaluating the micronucleus assay of buccal mucosa cells in smokers who smoked less or more than 10 years. Materials and Methods: The present study has been a historical cohort study. The smokers were divided into two groups: First group include individuals with a smoking history less than 10 years (14 samples) and second group with the smoking history of more than 10 years (26 samples).The control group consisted of nonsmokers (23 samples). The exfoliated buccal mucosa cells were scrapped using spatula and were spread over the glass slide. Feulgen method was used for micronucleus staining. 500 cells per subjects were counted. The presence of micronucleus in all subjects and the mean percentage of micronucleus in nuclei were determined. Data were subjected to statistical analysis using T-test. Results: The mean number of micronucleus of buccal mucosa cells in nonsmokers, first group (smoking history less than 10 years) and second group (smoking history more than 10 years) was 0.94 ± 0.94, 1.89 ± 0.62 and 2.01 ± 0.93 respectively. The difference was statistically significant (P < 0.002). Considering the number of micronuclei of the buccal mucosa cells, the difference between groups 1 and 2 was not significant (P < 0.6). The mean percentage of micronucleated cells in nonsmokers, group 1 and group 2 was 2.26 ± 2.17%, 13.9 ± 5.90 and14.3 ± 7.97, respectively. The difference was statistically significant (P < 0.001).The difference between the percentage of the cells with micronucleus in smokers with a smoking history of less or more than 10 years was not significant (P < 0.6). Conclusion: The mean number of micronuclei in buccal mucosa cells of the nonsmokers was significantly lower than that of the smokers. However, the mean number of micronucleus of buccal mucosa cells in smokers who smoked more than 10 years was higher than smokers who smoked less than 10 years. Increasing the smoking duration could heighten the frequency of micronucleus; however, the difference was not significant.