Abstracts

Rationale: Perinatal hypoxic ischemic encephalopathy (HIE) and prolonged febrile seizures (FS) are neurologic burdening problems in childhood period. Clinical studies suggest that prolonged febrile seizures (FS) in children can induce the hippocampal injury and later mesial temporal lobe epilepsy (MTLE). But the evidence of that FS can induce directly hippocampal injury is not sufficient in experimental studies. We studied cognitive function and histological change and investigated which is more burden among FS and HIE and dual pathologic effect.Methods: A rat model of HIE was made by completed cut of right common carotid artery followed by hypoxia (8% oxygen) at postnatal day 7 (P7). A FS model was made by heated stream and controlled to have seizures over 20 minutes at P10. We investigated the behavioral and cognitive function by weekly open field test at P3rd-7th weeks weekly and the Morris water maze test at 8th week daily and observed hippocampal pathologic change on control, HIE, FS and HIE+FS groups. Results: The HIE group was prone to seizures by hyperthermia. In the open field test and Morris water maze test, the HIE+FS and FS groups showed mild anxiety behavior, and HIE+FS and HIE groups showed decreased cognitive function than FS and control groups. Also the HIE+FS and HIE groups showed significant hippocampal neuronal damage, astrogliosis and volume loss in hippocampus in adult brain. FS itself induced minimal hippocampal neuronal damage without astrogliosis and volume loss. Conclusions: We concluded that hypoxic-ischemic injury is more burden injury than prolonged febrile seizure and FS can minimally effect on hippocampal neuronal damage in immature brain.