Comparative Study of Genotoxicity in Different Tobacco Related Habits using Micronucleus Assay in Exfoliated Buccal Epithelial Cells

Abstract

Background: Oral cancer is one of the most debilitating diseases afflicting mankind. Consumption of tobacco in various forms constitutes one of the most important etiological factors in initiation of oral cancer. When the focus of today's research is to determine early genotoxic changes in human cells, micronucleus (MN) assay provides a simple, yet reliable indicator of genotoxic damage. Aims and Objectives:To identify and quantify micronuclei in the exfoliated cells of oral mucosa in individuals with different tobacco related habits and control group, to compare the genotoxicity of different tobacco related habits between each group and also with that of control group. Patients and Methods:In the present study buccal smears of 135 individuals with different tobacco related habits & buccal smears of 45 age and sex matched controls were obtained, stained using Giemsa stain and then observed under 100X magnification in order to identify and quantify micronuclei in the exfoliated cells of oral mucosa. Results:The mean Micronucleus (MN) count in individuals having smoking habit were 3.11 while the count was 0.50, 2.13, and 1.67 in normal control, smoking with beetle quid and smokeless tobacco habit respectively. MN count in smokers group was 2.6 times more compared to normal controls. MN count was more even in other groups when compared to normal control but to a lesser extent. Conclusion:From our study we concluded that tobacco in any form is genotoxic especially smokers are of higher risk and micronucleus assay can be used as a simple yet reliable marker for genotoxic evaluation.

The smokeless tobacco habit and DNA damage: A systematic review and meta-analysis

“…Different tobacco mixtures were evaluated in the 25 studies. The majority of studies evaluated maras powder (13,16,17) and betel quid (1,12,28).…”

“…Other chromosomal aberrations, such as pycnosis, binucleated cells, anucleated cells, are excellent biomarkers of exposure to the chromosome-damaging agents in tobacco (11). For the evaluation of MN or other DNA damage different staining methods can be used, such Feulgen (11), Giemsa (12) or Papanicolau (13).…”

Study of acute genotoxic potential of an aqueous extract of Schinus terebinthifolius Raddi: an in vivo micronucleus assay

“…Micronuclei are developed during telophase of mitosis or meiosis, when the nuclear envelope is reconstituted to the contour of the chromosomes of the daughter cells. Derived from acentric chromosome fragments or whole chromosomes that are not incorporated in the main core, micronucleus represents the chromatin loss as a result of chromosomal damage in its structure (fragment) or damage to the mitotic apparatus [5][6][7][8][9].…”

“…Micronucleus are formed regardless of the type of injury during the cell cycle. Thus, the DNA damage caused, for example, by exposure to a genotoxic agent given, only manifest as a micronucleus after a cell division cycle, being dependent on the proportion of cells that are on division [7,10,11]. However, the micronucleus formation can occur spontaneously in the body.…”

Reporting an Experience: Improving the Feulgen Staining Technique for Better Visualizing of Nucleus

“…The genotoxic agents of tobacco, waterpipe and even environmental contaminants are recognized as initiator factors in producing the aberrations that results in MN production ( 3 - 5 ). Assessing the frequency of MN in oral exfoliated cells is a non-invasive reliable indicator of genotoxic damage in human ( 6 ).…”