Genotoxicity in lymphocytes of smokers living in México City

the genotoxic damage that tobacco smoke produces in active smokers was evaluated using cytokinesis-blocked micronucleus assay. the effect of tobacco smoke on the cellular cycle was analyzed by means of nuclear division index (ndi) and cytokinesis proliferation block index (cpbi). the results indicated a significantly lower frequency of micronuclei (mn) in the smoker group than in the control group. the nuclear division and cytokinesis proliferation block indexes indicated a delay in the cellular cycle of smokers and controls. the delay was greater in the controls (non-smokers) compared to smokers. nicotine and cotinine contents in the urine samples of the subjects of both groups were also measured using gas chromatography/mass spectrometry; significantly higher levels were found in smokers, while values for controls could not be established accurately due to the fact that they fell below the limits of resolution accepted by the mass spectrometer. in general, no association was established between evaluated cytogenetic variables -binucleated (bn) cells with mn, total mn, ndi and cpbi- and nicotine and cotinine contents in smokers. however, when the information was analyzed according to subgroups -light, moderate and heavy-, an increase in correlation coefficients was found. the same strategy was used to analyze the rest of the cytogenetic variables and nicotine and cotinine. the results indicated that only the light-smoker subgroup exhibited a significant correlation coefficient between nicotine and the number of bn cells with mn.