Abstracts

The neuroprotective effect of a free radical scavenger, N-tert-butyl-alfa-phenylnitrone (PBN), was well documented in numerous studies. The present study was designed to examine effects of PBS on long-term functional consequences of status epilepticus (SE) in immature rats. SE was induced by lithium-pilocarpine at the age of 12 (P12) or 25 (P25) days. PBN was injected intraperitoneally in two doses (100 mg/kg each) 1 and 60 min after SE onset. Non-treated animals received saline instead of PBN, other treatments were identical. Each age group consisted from at least 8 experimental and 8 control rats. In order to decrease mortality all animals received paraldehyde (0.07 or 0.3 ml/kg, according to the age) 2h after SE onset. Effects of PBN on severity of SE and mortality were registered. Functional outcome of treatment was assessed 3 months later. Motor abilities were tested by horizontal bar and roto-rod. Morris water maze was used to test cognitive abilities. Video/EEG monitoring was used to detect spontaneous seizures. PBN administration did not affect SE or mortality in any age group. Motor performance of SE animals did not differ from that of control rats. Learning abilities were improved 3 months after SE in P25 animals treated with PBN compared to non-treated controls. No difference occurred in P12 group. Video/EEG monitoring demonstrated tendency to decreased incidence of animals with spontaneous seizures in P12 group treated with PBN (25%) compared to non-treated animals (50%). Difference was, however, not significant. In contrast, PBN treatment in P25 rats resulted in increased seizure frequency 3 months after SE compared to non-treated animals (28+12 vs. 5+2 seizures/24h). In addition, number of epileptic animals tended to be higher in PBN-treated group (100% vs. 71%). Long-term outcome of PBN treatment was highly age dependent. Administration of PBN during SE in P25 resulted in partial protection of cognitive function and significant worsening of epilepsy. In P12 rats, PBN treatment tended to suppress epilepsy development. (Supported by Grant No 304/05/2582 of the Grant Agency of the Czech Republic.)