Study of in Vitro Frequency of Micronuclei in Short-term Cultured Blood Lymphocytes in Subjects with Long Term Exposure to Tobacco

Abstract

Cytokinesis Blocked Micronucleus (CBMN) assay is widely used biomarker for measuring anomalies like chromosome breakage and chromosome missegregation. Chromosome breakage can occur due to exposure to various carcinogens including chemicals, drugs, alcohol and environmental factors. Micronucleus frequency is also influenced by the age, diet and gender. Tobacco smoking is a significant source of exposure to a large number of substances known to be hazardous to human health. Smoking causes DNA single strand breaks, DNA adducts and oxidative damage to DNA. Here whole blood samples were taken from smokers (10-20 cigarettes/day) and non smokers. Samples were cultured and allowed to complete one cell cycle and were arrested at the cytokinesis stage by using Cytochalasin –B which gave the binucleated cells. 1000 binucleated cells were scored to see the presence of micronucleus. Mitotic index of each sample was also calculated which depends on each individuals response to PHA (a mitogen stimulating agent). KEY WORDS: Micronucleus, Cytokinesis Blocked Micronucleus assay, tobacco smoking, Cytochalasin-B, PHA.