Pesticide-induced primary DNA damage in peripheral blood leukocytes of farm workers evaluated by the computerized 'comet' assay

The alkaline single-cell microgel-electrophoresis ('comet') assay, allowing the evaluation of damage occurring at the DNA level in individual cells associated with exposure to genotoxic compounds, appears to be a promising tool for human biomonitoring studies. In a molecular epidemiology approach aimed at evaluating the eventual genetic damage induced by occupational exposure to pesticides, peripheral blood leukocytes of 17 male farm workers and of 17 age-matched controls living in the same area were analysed for the presence of DNA damage using the 'comet' assay. In this paper we report results obtained after a re-analysis by a computerized system of photomicrographs previously used for the direct manual measurement of comet length. Exposed subjects (farm workers) showed a statistically significant increase in the number of damaged cells (cells with an abnormal size tail, AST) for the tail length parameter, as compared with controls. We did not observe any statistically significant effect of cigarette smoking on the extent of DNA damage (both exposed and controls) and trends similar to those obtained for the groups in toro were observed when smoking habits was considered. Our results support data reported in the literature indicating that occupational exposure to pesticides may evoke some genotoxic effect and, consequently, confirm the necessity to improve preventive measures and to perform accurate health surveillance of individuals exposed to pesticides.