Effect of Vitamin E on Blood-Brain Barrier Permeability in Aged Rats with PTZ-Induced Convulsions

The effect of vitamin E on blood-brain barrier (BBB) permeability was studied under conditions of pentylenetetrazole (PTZ)-induced convulsions in aged (23- to 24-month-old) male albino rats; Evans Blue was used as a tracer. The BBB permeability was found to increase considerably in rats with PTZ-evoked seizures; the Evans Blue contents in the left and right hemispheres and cerebellum + brainstem region were significantly higher than those in the control. Vitamin E at a dose of 70 mg/kg exerted practically no beneficial effect on the increased BBB permeability in rats with seizures, while a greater dose of vitamin E (700 mg/kg) exerted a significant protective effect, especially with respect to the cerebellum + brainstem regions (P < 0.01). The seizure-related rise in the arterial blood pressure was also smaller in the latter experimental group. Thus, our observations confirm the importance of the vitamin E dose as a protective factor for BBB permeability and demonstrate that the dose dependence of this antioxidant in aged animals differs from that in younger organisms.