Micronucleus assay- an early diagnostic tool to assess genotoxic changes in tobacco and related habits

Micronuclei are induced in cells by a variety of substances, like UV radiation, infrared rays, X-radiations, and chemicals. Among them tobacco- specific nitrosamines have been reported to be potent mutagenic agents which are thought to be responsible for the induction of chromosomal aberrations resulting in production of micronuclei. The main aim of our study is to compare MN frequency among subjects, chewing tobacco only, chewing and smoking tobacco only, and chewing, smoking with alcohol, and to co-relate with control subjects. Healthy subjects are included in the study and divided into four groups having 20 subjects in each group. Group-I is chewing only, group-II chewing and smoking, group-III chewing and smoking with alcohol, group-IV control. Smears were made from buccal exfoliated cells and stained with DNA specific stain Acridine orange. Frequency on MNC per 100 cells was assessed with, one way ANOVA & Tukey HSD Multiple Comparisons test with P<0.05. The mean number of MN was 2.3, 2.4, 3.6 in the group of chewing only, chewing & smoking, chewing, smoking & alcohol respectively. While assessing MN in the controls, out of 20 cases, 19 showed no MN among the cells examined while 1 patient showed 1 MN each per 100 cells examined. The present study concludes that MN is a better surrogate biomarker to predict genotoxicity for tobacco related habits.