Evaluation of DNA damage in leukocytes of ex-smokers by single cell gel electrophoresis.
Single cell gel electrophoresis (SCGE), or comet assay, appears to be a promising tool to estimate DNA damage at the single cell level and it provides information on the presence of damage among individual cells. A follow-up study of 90 smokers who ceased smoking was undertaken to determine the possible decrease of DNA damage in their leukocytes. Before beginning the trial, volunteers smoked on average 26.1 +/- 8.4 cigarettes/day. Comet length did not correlate with the number of cigarettes/day or with the condensate tar content. At the end of the study, 28 volunteers had abandoned the trial, 40 volunteers relapsed into smoking at different times, but with a reduced number of cigarettes/day, whereas 22 fully succeeded in smoking cessation. Throughout the 5 sampling times, a great variability of comet length at individual level was found. However, after 1 year of follow-up, comet length means were found to be significantly shorter (p < 0.0001) in those volunteers who completely quit smoking compared to those who relapsed into smoking (27.2 +/- 1.6 vs. 31.9 +/- 5.1 microns, respectively), irrespective of the amount of cigarettes previously smoked. No effect of age or sex was found. Six months later, these results were confirmed by a further study carried out on a reduced sample of volunteers. The present data strongly suggest that, in spite of the great variability observed, 1 year of smoking cessation is associated with a significant reduction of DNA damage in circulating leukocytes.
Frenzilli
G
G
Dipartimento di Scienze dell'Ambiente e del Territorio, Università degli Studi Pisa, Italy.
Betti
C
C
Davini
T
T
Desideri
M
M
Fornai
E
E
Giannessi
L
L
Maggiorelli
F
F
Paoletti
P
P
Barale
R
R
D000328:Adult; D000368:Aged; D002248:Carbon Monoxide / Q000032:analysis; D004249:DNA Damage; D004252:DNA Mutational Analysis / Q000379:methods*; D004587:Electrophoresis, Agar Gel / Q000379:methods; D005500:Follow-Up Studies; D006801:Humans; D007962:Leukocytes / Q000737:chemistry*; D008875:Middle Aged; D009152:Mutagenicity Tests / Q000379:methods*; D012907:Smoking; D013997:Time Factors
D002248:Carbon Monoxide