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The Pilocarpine Model of Temporal Lobe Epilepsy and EEG Monitoring Using Radiotelemetry System in Mice
Published on: February 27, 2018
Disruption of cortical development as a consequence of repetitive pilocarpine-induced status epilepticus in rats
Alexandre Valotta da Silva1, Maria Cristina Regondi, Esper Abrão Cavalheiro
1Universidade Federal de São Paulo, São Paulo, Brazil. valotta.nexp@epm.br
Insights
Repetitive seizures in developing rats caused abnormal brain development, altering neural circuits and interneuron function. This acquired disruption mimics aspects of childhood epilepsy with cognitive issues.
Area of Science:
- Neuroscience
- Developmental Biology
- Epilepsy Research
Background:
- Status epilepticus (SE) can impact brain development.
- Understanding acquired cortical abnormalities is crucial for epilepsy research.
Purpose of the Study:
- To investigate cortical abnormalities following repetitive pilocarpine-induced SE in developing rats.
- To analyze changes in neuronal markers and circuitry development.
Main Methods:
- Wistar rats underwent pilocarpine-induced SE on postnatal days 7-9.
- Immunocytochemistry was used to examine neurofilament, parvalbumin, calbindin, calretinin, and glutamate decarboxylase expression.
- TUNEL assays and double-labeling were performed on brain sections at postnatal days 10 and 35.
Main Results:
- Observed altered intracortical circuitry development.
- Detected altered parvalbumin (PV) immunoreactivity in neocortical interneurons.
- Found increased glutamate decarboxylase 65 (GAD-65) immunoreactivity.
- Noted a reduced neocortical apoptotic process.
Conclusions:
- Repetitive SE in developing rats leads to acquired disruptions in cortical development.
- These disruptions share characteristics with childhood epilepsies associated with cognitive impairment.
- The findings suggest a potential model for studying epilepsy-related cognitive deficits.
Purpose:
The aim of the present study was to observe possible cortical abnormalities after repetitive pilocarpine-induced status epilepticus (SE) in rats during development.
Methods:
Wistar rats received intraperitoneal injection of pilocarpine hydrochloride 2% (380 mg/kg) at P7, P8, and P9. All experimental rats displayed SE after pilocarpine injections. Rats were killed at P10 and P35, and immunocytochemistry procedures were performed on 50-microm vibratome sections, by using antibodies against nonphosphorylated neurofilament (SMI-311), parvalbumin (PV), calbindin (CB), calretinin (CR), and glutamate decarboxylase (GAD-65). Selected sections were used for the TUNEL method and double-labeling experiments, with different mixtures of the same markers.
Results:
The major findings of the present work were (a) altered intracortical circuitry development; (b) anticipation of PV immunoreactivity in neocortical interneurons; (c) increased GAD-65 immunoreactivity; and (d) reduced neocortical apoptotic process.
Conclusions:
From these results, we suggest that previously healthy brain, without genetic abnormalities, might develop an "acquired" disruption of cortical development whose evolution reproduces some characteristics of the childhood epilepsies associated with cognitive impairment.
