Hippocampal gliosis in a genetic model of temporal lobe epilepsy

Hippocampal sclerosis is the most common pathology identified in human temporal lobe epilepsy (TLE) and is characterized by neuronal degeneration and astrocytic gliosis. The neuronal loss involves the hippocampus proper and dentate gyrus. The astrocytic gliosis involves an increase in the number of glial cells and in the amount of glial fibrillary acidic protein (GFAP). The El (epileptic) mouse is considered a model for human TLE. Histological evaluation of hippocampal sections revealed no obvious neuronal loss in adult seizing El mice. The mean number of GFAP-positive cells was approximately 15 to 40 fold higher in adult seizing El mice than in controls. Relative GFAP concentration was 2.7 fold greater in the hippocampus of adult seizing El mice than in controls. Astrocytic gliosis is present in the hippocampus of adult El mice without the presence of obvious neuronal loss.