Study Of The Changes In The Expression Of Nerve Growth Factor And The Ultrastructure In CA3 Of Rat's Hippocampus After Epilepsy

Objective: To study the changes in the expression of nerve growth factor(NGF) and the ultrastructure in CA3 of rat's hippocampus, and to explore the relationship between them and the formation of an excitatory neural network and their reconstitution in the hippocampus after epilepsy.Methods: Epileptic seizure was induced in adult model rats following the introduction of kainic acid in the lateral cerebral ventricle by micro-injection. NS control and experimental groups were set up. The expression of NGF, reconstitution of synapses and the change of nucleus and chondriosomes of neurons after epilepsy in CA3 of the rat's hippocampus were observed at 1,3 and 7days interval by using methods of immunohistochemistry and immune electron microscope.Results:(1) The expression of NGF: the expression of NGF in CA3 of the rat's hippocampus after epilepsy began increasing at day 1 and achieved a peak at day 3 .It decreased at day 7 ,but still remained higher than NS control group.(2)Para-meters of synaptic activity:the synaptic number in CA3 of rat hippocampus after epilepsy decreased at day 3 and increased at day 7. Synaptic posterior membrane began thickening and synaptic gaps began widening at day 3. (3) The change in nucleus and chondriosomes of the neurons:the damage in the nucleus and chondriosomes in CA3 became more severe as time progressed.Conclusion: The expression of NGF in CA3 in the rat's hippocampus increased rapidly and lasted some time after micro-injection of kainic acid in the lateral cerebral ventricle. We can precisely locate and quantify NGF through the second antibody labeled by gold particle. We can also observe neuronic apoptosis and the synaptic activity including changes of synaptic numbers, thickening of the sy-synaptic posterior membrane and widening of the synaptic gap at the same time. This implies the increase in endogenous NGF may affect recurrent attacks of epilepsy through inhibition of neuronic apoptosis and enhancement of mossy fiber sprouting. Neuronic apoptosis and mitochondrial vacuolization in CA3 of the rat's hippocampus affect the normal physiological process and provid the pathological foundation for recurrent attacks of epilepsy.