Antioxidant defense system in rats simultaneously intoxicated with agrochemicals.

The effect of dimethoate, zineb and glyphosate administered alone or in combination on liver, kidney, brain and plasma antioxidant defense system was investigated. Lipid peroxidation, and RNS production were increased in all tissues studied, especially in those groups that received a combination of drugs. Intoxicated rats exhibited lower antioxidant ability, higher oxidized protein and glutathione levels in plasma with a decreased concentration of α-tocopherol in brain and liver, between 30% and 60% of control. Superoxide dismutase was decreased in liver and brain. Glutathione reductase was inhibited in liver while glutathione peroxidase and transferase were unaffected. Plasma lactate dehydrogenase and γ-glutamyl transpeptidase activities were both increased. The associations of drugs produce more damage than individual administration being the effects observed strongly dependent on the kind of tissue analyzed. In conclusion, the present paper evidenced both the role of the oxidative stress as a mechanism of action of some pesticides and the potential additive effects of a simultaneous exposure to more than one compound. In addition, results suggest a potential contribution of pesticide mixtures to the aetiology of some neurodegenerative diseases.