Induction of status epilepticus during the light/dark phases of day and effect on hippocampal neuronal cell death in the developing rat

摘要

Introduction: Status epilepticus (SE) is a neurological condition characterized by continues seizures during a prolonged period or by seizures occurring so frequently that patient does not fully recover from one seizure before having another. SE occurs with high incidence in children and causes neuronal cell death in several brain regions, mainly in the hippocampus. Evidence shows a circadian variation in epileptic seizure progression in both, humans and experimental models of epilepsy.Objective: To study the effect of the light/darkness cycle on seizure activity during SE induced in developing rats and on hippocampal neuronal damage.Material and Methods: SE was induced in fourteen days old rat pups either during the light or darkness phase of day by using the lithium-pilocarpine model. Seizure severity was evaluated during SE and 24 h later, neuronal cell death in hippocampus was analyzed with hematoxylin-eosin staining.Results: Incidence, latency and duration of SE in developing rats were similar when induced during the light and darkness phases of day. SE produced neuronal cell death in subiculum-CA1 and dentate gyrus fields, effect that was independent of light-darkness periods.Conclusion: No differences were detected in seizure severity when SE was induced during the light or darkness phases of day in the immature rat, neither in the neuronal cell death observed in the hippocampus.