The
DNA damaging and proapoptotic effects of
Mancozeb, a widely used fungicide of the
ethylene-bis-dithiocarbamate (EBDC) group, were studied in RAT-1 fibroblasts cultured in vitro and in peripheral blood mononucleated cells (PBMC) isolated from Wistar rats. After 1 h exposition to
Mancozeb (up to 500 ng/ml), cells produced a dose-dependent induction in
DNA single strand break (SSB) formation, measured by single cell gel electrophoresis (SCGE). Concomitantly, a concentration-dependent increase in the levels of the oxidative markers of
DNA oxidation, the
DNA adduct 8-hydroxy-2'-deoxyguanosine (8-OHdG) and of
reactive oxygen species (ROS) were observed, suggesting a prooxidant action of
Mancozeb. PBMC were less responsive than fibroblasts to the oxidative insult carried out by
Mancozeb, as shown by the lower increase in the levels of ROS, 8-OHdG adducts and SSB measured in these cells after exposure to the
pesticide. A 4-h treatment with
Mancozeb induced also apoptosis in both PBMC and RAT-1 cells, even though leukocytes were less sensitive than fibroblasts to the proapoptotic action. This effect was dose-dependent and was inhibited by the action of the
antioxidant alpha-tocopherol. The proapoptotic effect was accompanied by the altered expression of several
proteins involved in the regulation of apoptosis, such as the prosurvival
protein BCL-2 and the proapoptotic
protein c-MYC. Exposition of cells to higher concentrations of
Mancozeb or for longer periods (>4 h) caused post-apoptotic, necrotic alterations in cell membrane integrity. The data herein presented demonstrate the oxidative effect of
Mancozeb and suggest that its prooxidant action may be involved in the proapoptotic effect exerted by this compound in rat cells. It appears possible that the observed oxidative and genotoxic damage may be involved in the pathogenesis of various pathologies associated with the chronic exposition to
Mancozeb, including
cancer. On the other hand, the proapoptotic effect of
Mancozeb suggests its possible relevance in the pathogenesis of
neurodegenerative diseases, often related to the exposition of pesticides.