Antiperoxidant pretreatment and iron-induced epileptiform discharges in the rat: EEG and histopathologic studies.

Iron causes formation of superoxide radicals resulting in peroxidation of membranous components of tissue. Hemosiderin deposition in human brain often accompanies chronic posttraumatic seizures induced by trauma. We injected an aqueous solution of iron salts, the principal metallic iron of whole blood, into rat isocortex. Serial electroencephalographic recording showed than 94% of untreated animals developed epileptiform discharges. Pretreatment with alpha-tocopherol and with 2 ppm selenium prevented development of iron-induced epileptiform activity in 72% of animals. Histopathologic assessment of serial sections stained with Nissl, hematoxylin and eosin, and prussian blue showed cavitation, neuronal pyknosis and loss, and astrogliosis in untreated animals. The site of iron injection in animals treated with antiperoxidants contained only an area of neuronal pyknosis. The efficacy of antioxidants in preventing development of iron-induced cavitation, gliosis, and epileptiform discharges suggests that peroxidative injury may be important in the development of experimental epilepsy induced by isocortical injection of ferrous chloride.