Effects of epigallocatechin-3-gallate on pentylenetetrazole-induced kindling, cognitive impairment and oxidative stress in rats

Cognitive dysfunction is commonly observed in epileptic patients. It has been shown that not only epilepsy but also antiepileptic drugs could induce cognitive impairment. Thus, there is an urgent need for drugs that can suppress seizures without causing cognitive deficit. Recent studies have shown that oxidative stress is involved in the pathophysiology of epilepsy, and many antioxidants have an antiepileptic property. Epigallocatechin-3-gallate (EGCG), a catechin polyphenols component, is found to be an effective antioxidant. The purpose of this study was to assess the effect of EGCG against seizures, seizure-induced oxidative stress and cognitive impairment in pentylenetetrazole-induced kindling. Male Sprague-Dawley rats were injected intraperitoneally with a dose of 35 mg/kg of pentylenetetrazole (PTZ) once every alternate day for 13 injections. EGCG was administered daily in two doses (25mg/kg and 50mg/kg) intraperitoneally along with alternate-day PTZ. Morris water maze test was carried out 24h after the last injection of PTZ, and the oxidative stress parameters (malondialdehyde and glutathione) were assessed after the completion of the behavioral test. The results showed that EGCG dose-dependently suppressed the progression of kindling. EGCG also ameliorated the cognitive impairment and oxidative stress induced by PTZ kindling. These observations suggest that EGCG may be a potential agent for the treatment of epilepsy as well as a preventive agent against cognitive impairment induced by seizure.