Thalamic neuropathology in the chronic pilocarpine and picrotoxin model of epilepsy

Adult male Wistar rats were injected with 150/0.5, 75/1.5 and 50/2.0 mg/kg of pilocarpine (Pilo) and picrotoxin (PTX) (Pilo/PTX mg/kg). The vast majority of the animals developed status epilepticus (SE), after which they were observed for a period of 120–131 days for the occurrence of spontaneous recurrent seizures (SRS). After the experiments, animals were deeply anesthetized, perfused with a 10% formaldehyde fixative solution and their brains were processed with cresyl violet, Perls and Von Kossa techniques. Cell counts were performed under a regular microscopic grid in diverse anteroposterior levels of the thalamus. Several thalamic nuclei in the epileptic groups, particularly the central medial, central lateral, paracentral, mediodorsal, laterodorsal and lateroposterior, showed intense cell loss, pathologic calcification and iron tissue deposits. Our results are relevant to support the importance of the thalamus in the pathogenesis of the epilepsies.