Chromosome alterations in peripheral lymphocytes as indices of lifestyle and genotoxicity

Summary

Short-term cultures of human lymphocytes were used to investigate the in vitro metabolism of benzene and its genotoxicity, and to monitor genetic health effects of lifestyles. Metabolic (S9) activation of benzene and its metabolites, catechol, hydroquinone, and phenol, caused an increase in sister-chromatid exchanges (SCEs) with different optimal concentrations of S9 mix for converting each compound into further reactive forms. The data indicate that catechol and hydroquinone can be optimally metabolized to produce reactive species, presumably benzo(semi)quinones, under conditions of lower metabolic activity than those necessary for phenol and benzene. We have further investigated the correlations between chromosome alterations (SCEs, structural aberrations and micronuclei) in peripheral lymphocytes and individual lifestyles. Healthy lifestyles, or “good health practices” examined were 1) not smoking, 2) not drinking too much alcohol, 3) doing physical exercise regularly, 4) sleeping more than 6 h per night, 5) keeping nutritional balance in meals, 6) not snacking, 7) having breakfast everyday, and 8) not having too much perceived stress. The persons were categorized into 3 groups having good, moderate and poor lifestyles by the number of good health practices they do. Mean frequencies of chromosome alterations in lymphocytes from men with poor lifestyles have been shown to be significantly higher than those in cells from men having good lifestyles. Further experiments have been done to examine whether lymphocytes from men having unhealthy lifestyles might show a higher susceptibility 1) to the SCE production by treatment with hydroquinone, a major metabolite of benzene, and 2) to the chemical's inhibitory effect of repair of radiation-induced chromosome breakage, because our living and working environments contain possible repair inhibitors such as benzene, lead and chromium. The results showed that unhealthy lifestyles could make the cells to be more sensitive to the production of these chromosome alterations by the environmental and occupational agents.