Alteration Of Mitochondrial Function In The Hippocampus Of Temporal Lobe Epilepsy Model

PARTⅠAN STUDY OF PATHOLOGY OF LITHIUM-PILOCARPINE MODEL OF TEMPORAL LOBE EPILEPSYObjective To investigate the alteration of behavior and pathology of lithium-pilocarpine model of temporal lobe epilepsy,and so to decipher seizure-dependent changes in neuronal injury in rat hippocampus after status epilepticus(SE) induced by pilocarpine(PILO).Methods Male Wistar rats received lithium-pilocaroine to induce status epilepticus(SE).After 1 h when the rats developed SE,they were treated by diazepam to stop SE.Afterwards all rats were monitored by video recordings to assure development of spontaneous recurrent seizures(SRS)and study the pathological changes with HE,Nissl and Timm staining at 3h,7d and 45d after SE induced by pilocarpine.Results After injection of lithium and pilocarpine,89%of the rats were induced to develop SE,and after a latency phase,average about 14.5±5.9,SRS could appear.The pathologic investigation using HE,Nissl and Timm staining showed the hippocampal neuronal damage and mossy fiber sprouting(MFS).Conclusions Epilepsy induced by lithium-pilocarpine develops in 3 periods acute period,silent period and chronic period(spontaneous recurrent seizures). Epileptic seizures induced by lithium-pilocarpine can cause neuronal damage and MFS in the hippocampus of rats. PARTⅡCHANGES OF EXPRESSION OF MITOCHONDRIAL CYTOCHROME OXIDASE SUBUNITS I AND IV IN THE HIPPOCAMPUS OF PILOCARPINE-TREATED RATObjective;To investigate the effects of epilepsy on expression of cytochrome oxidase(COX)subnuitsⅠ(COXⅠ)andⅣ(COXⅣ)encoded by mtDNA and nDNA respectively in rat hippocampus.Methods;Male Wistar rats were divided randomly into saline control group,acute period groups(3h),silent period group(7d),chronic period group(45d)after status epilepticus(SE)and group which received pilocarpine(PILO)but did not develop SE.The expression of COXⅠand COXⅣin rat hippocampus were detected respectively by immunohistochemistry.Results;An significant increase in COXⅠstaining was observed in neuronal cell bodies distributed throughout the hippocampus(CA1,CA2,CA3,dentate gyrus) of rats killed 3h after SE,when compared to the saline-treated group.On day 7 after SE,the immunoreactivity was slowly reducedand the immunoreactivity of cell bodies was restricted predominantly to the dentate gyrus,and CA3 regions of the hippocampus.The chronic period(45d)showed decreased staining with the findings indicating neuronal degeneration such as condensation of cell bodies,vacuolization and rearrangement of pyramidal cell layers in the CA3 of the hippocampus. saline-treated animals,animals that did not respond to PILO in our study showed similar results with that of control group.Conclusions;Dysfunction of COX in the hippocampus are associated with prolonged seizure during experimental temporal lobe epilepsy and mitochondria are more vulnerable to epilepsy.