Histological changes of the brain tissue in pilocarpine epileptic experimental model before and after the use of antiepileptic and antioxidant substances

ABSTRACT

Epilepsy is a chronic, dynamic neurological disorder associated with ongoing neuronal damage, particularly when uncontrolled. Systemic administration of pilocarpine to rats results in generalized tonic clonic seizures and subsequent neurodegeneration similar to that observed in certain types of human epilepsy. Brain damage is supposed to be secondary to free radical production, thus raising the theory of the use of antioxidants as neuroprotective substances. To throw light on the evidence for the role of oxidative injury in epilepsy, the brain damaging action of the antiepileptic drugs and the rationale for use of antioxidant therapy in epilepsy. Eighty adult albino rats were divided into 4 groups; group I served as a control, group II were injected with pilocarpine hydrochloride intraperitoneal for induction of seizures, group III were given phenytoin [antiepileptic drug] before pilocarpine injection, while group IV were given vitamin C before being injected with pilocarpine. The animals were observed for the frequency of fits and mortality rate. The brain tissue of the sacrificed rats were processed for both light microscopical and ultrastructural study. Animals that possessed seizures following pilocarpine injection showed increased vascularisation, neuronal loss, gliosis, and silver stained proliferated dendrites by light microscope. Ultrastructural study revealed nuclear and cytoplasmic vacuolization, and destruction of mitochondria. Animals treated with phenytoin although showed reduction of the number of convulsing animals and mortality rate, yet all pathological findings found in pilocarpine group were observed. Instead the use of vitamin C showed a significant protective effect on the brain tissue. Although there is a documented brain damage of epileptic seizures and also antiepileptic drugs, antioxidants have a protective action against these brain damaging effects