Avaliação subclínica da frequência de micronúcleos em células da mucosa bucal em pacientes fumantes e não fumantes

Abstract

The oral mucosa can be exposed to carcinogens, especially tobacco, becoming susceptible to cell damage due to the multiple reactive metabolites generated. Micronuclei are indicative of DNA damage and could contribute to the monitoring and understanding of the etiopathogenesis of subclinical lesions. However, this cellular diagnosis is little explored and quite heterogeneous in the scientific community. The objective of this study was to determine the frequency of micronuclei in epithelial cells of the healthy oral mucosa in smokers and non-smokers. It was performed a collection and fixation of exfoliated cells from oral mucosa in alcohol of 95%, it was used a cytobrush in the inner cheek mucosa, lateral border of the tongue and floor of the mouth of 16 patients of both sexes. They were separated into two groups: smokers (G1) and non-smokers (G2). After the cytological processing and Papanicolau test, the slides were analyzed with an optical microscope, 100 cells/sample were documented and 4800 images were analyzed, where the presence of micronucleated cells (MNC) and the number of micronuclei were counted per cell. Parametric data allowed intergroup and intragroup comparisons. It were considered the variables gender (male and female), anatomical regions, age (40-50 years and 50-60 years) and micronucleus per cell (1, 2, 3 or ≥4). It was used analysis of variance (ANOVA) and multiple Tukey comparisons with statistical significance of 5% (p <0.05). The total amount of MNC in G1 was almost double (50.53%) than G2. The frequency of MNC was more expressive in G1 for all the anatomical regions analyzed, with an increase of 72.49% in floor of mouth region. The other regions studied showed no significant differences. The presence of MNC between G1 and G2 did not show significant differences in men. For women, between groups G1 and G2, a significant difference was observed (p<0.01) reaching an increase of 72.38% in micro-nucleated cells in smoking patients. Regarding the age group of 40-50 years and comparing between groups G1 and G2, there was no significant difference. For the 50-60 year group of G1 and G2 respectively, there is a significant difference (p<0.05), which represents an increased frequency of 68.92% in micro-nucleated cells in G1 patients. There was a general prevalence of 1 and 2 micronuclei per cell in G1 and G2, with an increase of 46.68 and 67.5% respectively in G1. About the regions studied, the inner cheek lining, the lateral edge of tongue and the floor of mouth were significantly different between G1 and G2 (p<0.0001, p<0.01 and p<0.0001, respectively). These results indicate differences about the general presence of micronuclei and the number of micronuclei per cell between smokers and non-smokers, as well as between different intraoral anatomical regions, sex and age, suggesting that oral cytopathology may contribute to the sub-clinical diagnosis of cellular genotoxic alterations.