Smoking, alcohol affect DNA in cells

Study shows smoking and drinking alcohol cause formation of micronuclei

Smoking is a health hazard and how seriously it can impair human DNA has been vividly demonstrated in a recent study by researchers from Osmania University.

Measuring changes at cellular level in smokers and alcohol consumers, researchers have shown both smoking and consumption of alcohol cause formation of micronuclei, binucleate, karyolysis and karyohexis — cellular phenomenon associated with undesirable changes to DNA within the nucleus of a cell besides being biomarkers for exposure to toxic chemicals.

For the study, authors J. Karuna Kumari and K. Rudrama Devi used the Human Genetics and Toxicology Lab in the University’s Department of Zoology to study the cellular changes in buccal mucosa, lining inside of the mouth. They collected samples from 64 persons, mostly daily wage earners, who smoked or consumed alcohol, and compared them with oral mucus cells in 25 healthy individuals.

The findings showed an increased incidence of all the four cellular changes in individuals who either smoke or consume alcohol, with smoking associated with greater damage.

The incidence of undesirable changes increased with the number of years the participants had smoked for or had consumed alcohol, the researchers concluded.

Formation of micronuclei showed highest incidence in all groups, with smokers recording greater incidence. Micronuclei are often seen in malignant cells.

“When a cell divides, sometimes a part of chromosome may breakaway and form separate nucleus called micronuclei. This is usually seen in cancerous cells and also when exposed to geno-toxic chemicals,” Senior Principal Scientist at CCMB K. Thangaraj said.

The study’s researchers also showed that participants in the study group that reported both smoking and consuming liquor had greater incidence of all four undesirable cellular changes when compared to those who only smoked or consumed alcohol.

For instance, the incidence of micronuclei amongst the group that smoked and consumed alcohol was 20 per cent as against 9.9 per cent in smokers alone and 7.05 per cent in alcoholics.

However, incidence of karyolysis and karyohexis, phenomenona associated with a dying cellular nucleus, were similar for smokers and the group comprising of people that smoked and consumed alcohol.