The evaluation of effects of lipoic acid on the lipid peroxidation, nitrite formation and antioxidant enzymes in the hippocampus of rats after pilocarpine-induced seizures.

It has been suggested that pilocarpine-induced seizures is mediated by increases in oxidative stress. Current researches have suggested that antioxidant compounds may afford some level of neuroprotection against the neurotoxicity of seizures in cellular level. The objective of the present study was to evaluate the neuroprotective effects of lipoic acid (LA) in rats, against the observed oxidative stress during seizures induced by pilocarpine. Wistar rats were treated with 0.9% saline (i.p., control group), LA (10 mg/kg, i.p., LA group), pilocarpine (400 mg/kg, i.p., pilocarpine group), and the association of LA (10 mg/kg, i.p.) plus pilocarpine (400 mg/kg, i.p.), 30 min before of administration of LA (LA plus pilocarpine group). After the treatments all groups were observed for 6h. The enzyme activities as well as the lipid peroxidation and nitrite concentrations were measured using spectrophotometric methods and the results compared to values obtained from saline and pilocarpine-treated animals. Protective effects of LA were also evaluated on the same parameters. In pilocarpine group there was a significant increase in lipid peroxidation and nitrite level. However, no alteration was observed in superoxide dismutase and catalase activities. Antioxidant treatment significantly reduced the lipid peroxidation level and nitrite content as well as increased the superoxide dismutase and catalase activities in hippocampus of rats after seizures induced by pilocarpine. Our findings strongly support the hypothesis that oxidative stress in hippocampus occurs during seizures induced by pilocarpine, proving that brain damage induced by the oxidative process plays a crucial role in seizures pathogenic consequences, and also imply that strong protective effect could be achieved using lipoic acid as an antioxidant.