Effect of staining procedures on the results of micronucleus assay in the exfoliated buccal mucosal cells of smokers and nonsmokers: A pilot study

Abstract

Background: Tobacco consumption in smoke form causes severe health problems such as cancer. Micronuclei are structures that present after genomic damage in buccal mucosal cells which could be a good indicator of chromosomal alterations in cytological samples. The nuclear anomalies that are consequences of cell injury are also found in these cells.

Aim: The present study was aimed at evaluating the effectiveness of deoxyribonucleic acid (DNA)-specific stain over DNA-nonspecific stain in exfoliated buccal mucosa cells in smokers and nonsmokers for assessment of micronuclei and nuclear anomalies.

Materials and methods: Thirty subjects were divided into three groups; Group 1 (control) nonsmokers (n = 10), Group 2 individuals with history of smoking for less than 10 years (n = 10), and Group 3 individuals with history of smoking for more than 10 years (n = 10). The exfoliated buccal mucosal cells were scrapped using wooden spatula, smeared over the glass slide, and stained with DNA-nonspecific stain, Giemsa; and DNA-specific stains, Feulgen and acridine orange.

Results: We found that the mean micronuclei score with DNA-nonspecific stain, Giemsa, was significantly higher in smokers group when compared to nonsmokers group. No such significant differences were observed with DNA-specific stains. Also, in the smokers groups, mean micronuclei were higher in Group 3 when compared to Group 2.

Conclusion: The score of MN assay and nuclear anomalies in exfoliated buccal mucosal cells of smokers and nonsmokers strongly depended on staining procedures and duration of smoking. Hence, these should be interpreted with caution to avoid false-positive results.

Keywords: Acridine orange; feulgen; giemsa; micronuclei; nuclear abnormalities.