Hypothermia Reduces Brain Edema, Spontaneous Recurrent Seizure Attack, and Learning Memory Deficits in the Kainic Acid Treated Rats

Abstract

It is unknown whether hypothermia can disrupt the progress of epileptogenesis. The present study aimed to determine the effect of hypothermia on brain edema and epileptogenesis and to establish whether brain edema is associated with epileptogenesis after severe status epilepticus (SE). Rats were injected with a single dose of Kainic acid (KA) to produce either chronic epileptic rats (rats with spontaneous recurrent seizure, SRS) or rats without spontaneous recurrent seizure (no-SRS rats). A second KA injection was used to induce SE in SRS rats and in no-SRS rats. The number of SRS was counted and the brain edema induced by SE was assessed by brain water content measurement. The cognitive function was assessed by the radial-arm maze (RAM) test. A second KA injection resulted in brain edema that was more severe in SRS rats than in no-SRS rats. After second injection of KA, hypothermia treatment attenuated the KA induced brain edema and reduced the SRS attack in SRS rats. Additionally cognitive function was better in hypothermia-treated SRS rats than in nomothermia treated SRS rats 1 month after the second KA injection. Hypothermia treatment immediately after SE not only exhibited protective effects against the chronic spontaneous recurrent convulsant seizures but also improved cognitive function. These antiepileptogenic properties of hypothermia may be related to its attenuating effect on brain edema induced by SE. They therefore suggest that brain edema may be involved in the progress of epileptogenesis.