The features of neuronal loss in the hippocampus during acute generalized seizure (experimental study)

BACKGROUND: Today, epilepsy is one of the most frequently diagnosed neurological diseases. Despite more than several centuries of research on epileptogenesis and the development of treatment protocols, the neurobiological basis of the disease remains poorly understood. It is reliably known that patients with epilepsy are found to have a reduced number of hippocampal neurons and gliosis: mesial temporal sclerosis (hippocampal sclerosis), but the causal relationship with seizures has not yet been established. It is of particular interest to evaluate the survival of hippocampal neurons against the background of acute epileptic seizures, which will allow to determine the mechanisms of degenerative changes in nervous tissue. AIM: The aim of the study was to immunohistochemically assess the levels of NeuN and caspase-8 in the hippocampus during acute epileptic seizures. MATERIALS AND METHODS: Male mice of the CBA population were used as models. The animals were divided into groups: 1st (n = 28) simulated acute epileptic seizure by intraperitoneal injection of pentyltetrazole, 2nd (n = 20) control. Histological and immunohistochemical studies were performed on hippocampal fragments, regions: CA1, CA3 and dentate gyrus. RESULTS: Generalized epileptic seizures were noted in all animals of Group I. The weakest labeling of hippocampal pyramidal neurons with NeuN (light nuclei) was observed in CA3 region, which was observed 24 hours after pentyltetrazole injection. The same immunophenotypic pattern was observed in the CA3 region during reaction with caspase-8, which demonstrated an increase in the number of immunopositive hippocampal pyramidal neurons 24 hours after pentyltetrazole injection. CONCLUSIONS: After a single injection of pentyltetrazole at a dose of 45 g/kg, immunohistochemical evaluation of the distribution of NeuN- and caspase-8-positive pyramidal neurons of the hippocampus revealed: a decrease in the NeuN-positive neurons and an increase in caspase-8-positive neurons one day after the seizure with subsequent recovery of the studied markers by day 5.