Assessment of DNA damage in pulmonary tuberculosis patients by single cell gel electrophoresis / comet assay

Abstract

Background: The role of antitubercular drugs as anti bacterial agents on mycobacterium tuberculi is established.
However their impact on human cell is not much explored. Objective: The present study was aimed to determine the
extent of cell damage in Pulmonary Tuberculosis patients with the help of comet assay. This is a prospective study
carried out in Tiruchengodu Govt. Hospital from September 2011 to April 2012. Blood samples were collected from
100 subjects [Healthy volunteers (Go), newly diagnosed TB patients (G1), Three months treated TB patients (G2), Six
months treated TB patients (G3). n=25 subjects in each group]. Methodology: Blood samples from anticubital vein
were collected, embedded in agarose gel, lysed in high ionic strength solution with Triton X-100, and then
electrophoresed at pH>13, ethidium bromide stained were then subjected to analysis under Fluorescent microscope.
Results: Subjects of newly diagnosed TB (G1) patients did not show any remarkable cell damage as compared to TB
patients under treatment. Extent of cell damage in six months treated TB patients (G3) was greater than three months
treated TB patients (G2) (P<0.0001). Among quantitative comet metrics, comet length was significantly greater in
males compared with females (P= <0.0003). Extent of cell damage was observed significantly high in anti-tubercular
drug treatment patients both three months treated and six months treated TB patients.

Conclusion: DNA damage was
found to be significantly increased in smoking & alcoholic tuberculosis patients. Anti-tubercular drug and social habits
seem to be the major contributor of the cell damage