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Epileptogenesis in immature rats following recurrent status epilepticus
N F dos Santos1, R M Arida, E M Filho
1Neurologia Experimental, Universidade Federal de São Paulo - Escola Paulista de Medicina, Brazil.
Insights
Recurrent early-life status epilepticus (SE) in rats induced seizures and cognitive deficits in adulthood. These findings suggest early-life SE may contribute to long-term neurological changes.
Area of Science:
- Neuroscience
- Developmental Neuroscience
- Epileptology
Background:
- Childhood status epilepticus (SE) is linked to later epilepsy development.
- Pilocarpine-induced SE in rats after postnatal day 18 can cause later spontaneous seizures.
Purpose of the Study:
- To investigate if three pilocarpine-induced SE episodes in early life (postnatal days 7-9) cause long-term epileptic changes in adult rats.
- To assess behavioral, electrographic, and histological alterations following early-life SE.
Main Methods:
- Administered three pilocarpine-induced SE episodes to rats on postnatal days 7, 8, and 9.
- Performed EEG recordings at 30, 60, and 90 days.
- Conducted behavioral tests including inhibitory avoidance, Skinner box, rota-rod, open field, and elevated plus-maze.
Main Results:
- EEG recordings revealed spikes and polyspikes in the hippocampus and cortex at 30, 60, and 90 days.
- Only three isolated spontaneous seizures occurred during 120 days of observation.
- Adult rats exhibited increased exploratory activity, learning impairments, and reduced anxiety.
Conclusions:
- Recurrent early-life SE can induce long-term EEG changes in adult rats.
- Early-life SE is associated with cognitive deficits, including learning impairment and altered anxiety levels.
- These findings highlight the potential for early-life SE to contribute to neurological and behavioral changes later in life.
Abstract:
Strong evidences link status epilepticus (SE) in childhood with the later development of epilepsy. Pilocarpine-induced SE in developing rats leads to late appearance of spontaneous epileptic seizures only when SE is induced after the 18th day of life. We examined the possibility that 3 consecutive episodes of pilocarpine-induced SE on postnatal days 7, 8 and 9 could induce behavioral, electrographic and histological epileptic changes in adult life. The animals also underwent behavioral tests (inhibitory step-down avoidance, skinner box, rota-rod, open field and elevated plus-maze). EEG recordings made at the age of 30, 60 and 90 days showed the occurrence of several episodes of spikes and/or polyspikes appearing simultaneously in hippocampus and cortex. Only three isolated spontaneous seizures were observed during the whole period of observation (120 days). The long-term effects of three consecutive episodes of SE include increased spontaneous exploratory activity, learning impairment, and reduced anxiety when tested on P60. Our findings provide evidence for EEG changes and cognitive deficits in adult life following recurrent SE on postnatal days 7-9.