Influence of antioxidants on the blood-brain barrier permeability during epileptic seizures

Pentylenetetrazol-induced seizures in rats lead to the breakdown of the blood-brain barrier. We compared the disruption of the blood-brain barrier during epileptic seizure in untreated rats and in rats treated with vitamin E or selenium. The rats were supplemented with nontoxic doses of sodium selenite (4 pp) in drinking water for 3 months, or vitamin E (70 mg/kg) was given intraperitoneally for 30 min before the pentylenetetrazole injection. Evans-blue was used as a blood-brain barrier tracer and was given intravenously at a dose of 4 ml/kg of a 2% solution. The rats were divided into four experimental groups. Group I: control (n=24); Group II: pentylenetetrazole-induced seizure (n=12); Group III: vitamin E injected + seizure (n=12); Group IV: Selenium supplemented + seizure (n=12). The rats subjected to epileptic seizures showed Evans-blue albumin extravasations especially in the thalamic nuclei, brainstem, occipital, and frontal cortex. Mean values for Evans-blue dye were found to be 0.28 +/-0.04 mg % brain tissue in control rats and 1.6 +/-0.2 mg % brain tissue after epileptic seizures (P<0.01). The magnitude of distribution of the blood-brain barrier during epileptic seizures was significantly less in rats treated with vitamin E or selenium. The mean value for Evans-blue dye was found to be 1.20.1 mg % brain tissue in selenium supplemented rats and 1.2 +/-0.1 mg % brain tissue in vitamin E injected rats after epileptic seizures. This difference between treated and untreated animals was found to be significant (P<0.05). The findings of the present study suggest that free radicals contribute to disruption of the blood-brain barrier during pentylenetetrazol-induced seizures. J. Neurosci. Res. 66:674-678, 2001. (C) 2001 Wiley-Liss, Inc.