Abstracts

Status epilepticus early in life may have long term consequences. In this study we evaluated the effect of status epilepticus induced in immature rats on focal brain ischemia induced in adulthood.
Male Sprague Dawley rats at 15 days postnatal age (PN15) were submitted to status epilepticus by i.p. administration of 3.5 or 4.5 mg/kg of kainic acid, in order to induce [quot]mild[quot] or [quot]severe[quot] status epilepticus, respectively; the epileptic behavior and mortality were monitored. 4 weeks after status epilepticus the same animals were subjected to one 1-hour middle cerebral artery occlusion (MCAO) by the intraluminal filament technique. Twenty-four hours after MCAO the infarct volume for each rat was evaluated by computer scanning of 2 mm-brain sections stained with triphenyl-tetrazolium-chloride (TTC). Before sacrifice a graded neurological exam was determined using the following scale: 0=no deficit, 1= forelimb flexion, 2=decreased resistance to lateral push, 3= the same as 2 with circling.
Rats that experienced [quot]mild[quot] status epilepticus (characterized by scratching and wet-dog shaking; n=9) at PN 15 were not more prone to develop neurological deficits and larger size infarcts than controls (n=12). Rats that experienced [quot]severe[quot] status epilepticus (characterized by frequent bilateral clonic-tonic seizures; n=7) at PN 15 developed motor impairments significantly more frequently than littermate controls (Controls: grade 0=50%, grade 1=33.3%, grade 2=16.7%. Severe status epilepticus: grade 0=0%, grade 1=71.4%, grade 2=28.6%) (Fisher[rsquo]s Exact Test for grade 0 versus grade [ge] 1, p[lt]0.05); the mean infarct volume was also larger in this group.
These results suggest that the severity of infantile status epilepticus may influence the susceptibility to ischemic injury in adulthood.
[Supported by: NIH NS20253 and Heffer Family Medical Foundation (SLM); NIH EY11053 (DMR)]