Lipid peroxidation, oxidative stress and acetylcholinesterase in rat brain exposed to organophosphate and pyrethroid insecticides.

Oxidative stress by increased production of reactive oxygen species has been implicated in the toxicity of many pesticides. Therefore, the aim of the present study was to investigate the effect of a broad spectrum insecticide, composed of a mixture of organophosphate plus pyrethroids (fenitrothion 25%, lambda cyhalothrin 2.5% and piperonyl butoxide 6%), on antioxidant status and oxidative stress biomarkers in rat brain. Different insecticide concentrations (0, 0.1, 1, 10, 100 and 1000 mM) were incubated with brain homogenate at 37 °C for time intervals (0, 30, 60, 120, 180 and 240 min). Exposure to insecticide mixture resulted in a significant increase (p<0.05) in thiobarbituric acid reactive substances (TBARS), which might be associated with decreased levels of reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST) and acetylcholinesterase activities and beside protein content in rat brain. However, a significant induction of lactate dehydrogenase (LDH) activities was observed. The response was concentration and time dependent. Results showed that the used insecticides had the propensity to cause significant oxidative damage in rat brain, which is associated with marked perturbations in antioxidant defense system in addition to antioxidant enzymes can be used as potential biomarkers of toxicity associated with pesticides exposure.