Early Effects Of Gamma Knife On Synaptophysin And Mossy Fiber Sprouting In Hippocampus Of Rat Temporal Lobe Epilepsy Model

Chapter I Temporal lobe epilepsy model induced by lithium-pilocarpineObjectiveTo investigate the behavioral characteristics,alteration of electrophysiology and morphological changes of hippocampus in the lithium-pilocarpine model of temporal lobe epilepsy.MethodsAll Wistar rats were devided randomly into two groups :blank contral group and experimental group ,status epilepticus(SE) was induced by a single systemic injection of lithium chloride (127mg/kg), followed by pilocarpine (30 mg/kg) 18–24 hours later,after 1h when the rats developed SE ,they were treated by diazepam to stop SE .After that, a simple protocol for the daily observation of spontaneous seizures(SRS) ,electroenephalogram(EEG) was recorded awake phase before injection of pilocarpine,and was monitored in the process of SE and on 6w after SE. The brains were removed from the rats at different times respectively after SE, coronal sections were cut in a cryostat and processed for Nissl and Timm staining to study hippocampal neurons damage and changes of mossy fiber sprouting (MFS). Results84%(21/25) of the rats injected with pilocarpine developed SE .The SE rats showed SRS rang from stage I (I/V)to III(III/V) after a silence period for 10-20d. EEG showed the cluster of continuous high-amplitude spikes in acute phase ,and sporadic spikes in chronic phase respectively.The study of morphology indicated that widespread hippocampal neurons damaged and remarkably altered in the inner molecular layer (IML). As compared with blank control group ,the Timm staining score in IML was significantly increased.(P<0.05).ConclusionThe rat temporal lobe epilepsy model induced by lithium-pilocarpine is similar with human in behavioral characteristics,electrophysiology and morphological changes ,and it may be an ideal model for studying human temportal lobe epilepsy.Chapter II Early Effects of gamma knife on synaptophysin and mossy fiber sprouting in hippocampus of rat temporal lobe epilepsy modelObjectiveTo investigate early effects of gamma knife on synaptophysin(SYN) expression and mossy fiber sprouting(MFS) in pilocarpine-induced model of temporal lobe epilepsy and explore the mechanism of Gamma Knife radiosurgery for temporal lobe epilepsy, and so as to provide a theoretical basis for clinical practice.MethodsAll Wistar rats were devided randomly into three groups :blank contral group,treatment group and non-treatment group.Developed temporal lobe epilepsy model induced by lithium-pilocarpine, treatment group rats were treated by Leksell Gamma Knife on 2w after SE. Irradiation target was the left hippocampus,the central dose was 40Gy at the isodose line 70%.Immunohistochemistry and Timm staining were used to observe the expression of SYN and MFS in the inner molecular layer.ResultsAs compared with the non-treatment group ,treated rats showed reductions in the number of SRS in the latter of the study (Weeks 6-8). The expresion of SYN in IML was increased compared with blank contral group. As compared with the non-treatment group, treatment group SYN particles had different degrees of reduction in the left dentate gyrus IML. No significant difference between the two groups on 2h, (P>0.05); 2w-8w later difference between the two groups was statistically significant(P<0.05); treatment group the Timm staining score in the left dentate gyrus IML have different degrees of reduction, no significant difference between the two groups from 2h to 4w(P>0.05),8w later, it became significantly diffferent(P<0.05).ConclusionGamma Knife irradiation can inhibit the expression of SYN and reduce the MFS in IML in early stage,such a change may be one of the important mechanisms of Gamma Knife treatment of temporal lobe epilepsy.