Effect Of Topiramate And Gastrodium On The Expression Of Growth-associated Protein And Nestin In The Hippocampus Of PTZ-Kindled Rats

Objective: Epilepsy is a group of chronic disorders characterized by recurrent seizures,Seizure is a transient disturbence of cerebral function caused by abnormal neuronal discharge.The pathogenesis and etiology are complex and have not been well understood up to now.Neuroplasticity such as progressive neuronal loss,gliosis and synaptic reorganization have been found in different kind of epileptic models and human epileptic focus. Neuroplasticity during epileptogenesis has become the highlight in epileptic research in recent years. Kindling serves as a good kind of model for the research of epileptogenesis and neuroplasticity, Which resembles the epileptogenetic course in mankind. Growth-asscociated protein( GAP-43) is a kind of neuron-specific phosphoprotein that is mainly distributed in the membrane of axonal growth cones and presynaptic terminals, It is closely related with the development of the nervous system, nerve regeneration, neurite growth and the synaptic remodulation.Nestin is a kind of newly discovered intermediate filament protein,which locates in subventrical zone and dentate gyrus in adult brain physiologically.Astrocyte(AST) can express nestinpathologically,nestin can serve as a marker of reactive astrocytes. Topiramat is a sulfmate substituted monosaccharide and a relatively new antiepileptic drug with several putative anticonvulsant mechanisms. Tianxuanqing(gastrodium) can improve the function of gamma-aminobutyric acid receptor A resulting in antiepileptic and anticonvulsant efficacy. However, whether Topiramate or Gastrodium can serves as antiepileptogenetic drugs,and has effect on synaptic reorganization and gliosis, has not been reported. In the present study the PTZ-Kindled rats model were successfully reproduced, the effects of treatment with topiromate and gastrodium on rats behavior, EEG and expression levels of growth-associated proteins and nestin were investigated.Methods: 40 healthy male rats were randomly divided into 4 groups (n=10), The rats in PTZ kindled group (group II ) were intraperitonealy(i.p) injected PTZ 35mg/kg 1 h after intragastricaly injected nomal saline3.5ml/kg, the rats in TPM-treated group( group III ) were intragastrically(i.g) injected TPM 100mg/kg lh before ip-PTZ 35mg/kg; the rats in Gastrodium-treated group( groupIV ) were intragastrically injected Gastridium 100mg/kg lh before ip-PTZ 35mg/kg; the rats in control group (group I) were injected the same amount of nomal saline (NS) as other groups twice at a lh interval. All performances were undertaken during the course of 8: 00-10: 00 am. daily for 4 weeks. 4 rats in kindled group were subjected to EEG after reaching the criterion of kindling,4 rats from other individual group were subjected to EEG after beening treated 4W. All rats were sacrificed 6h after the last injection of PTZ, and were perfused transcardially with nomal saline and then cold PBS containing 4% paraformalolehyde. The dislodged brain tissues containing hippocampus were fixed in the same fixative solution for anther 24h, paraffin sections were made. The expression levels of GAP-43 and nestin in hippocampus were indicated by immunohistochemical method and quantified by HPIAS-1000.Result: PTZ-treated rats reached kindling criterion in about 28 days. In TPM-treated and Gastrodium-treated rats, seizure severity significantly decreased, none of themreached the kindling criterion. The rats in control group behaved normally without seizures. EEG of PTZ-treated rats showed typical spike-and-waves. In TPM-treated and Gastrodium-treated rats, the epileptiform discharge was markedly suppressed. EEG of control group show no epileptiform discharge. Using imrnunohistochemical method, we obtained the following results: In all four groups, GAP-43 immunostainnig in the hippocampus was characterized by a laminar distribution pattern, maily like spot- or grain-like deposit. Whereas, as compared with control group, the optical density of GAP-43 immunostaining significantly increased in the mossy fiber layer of area CA3(p<0.05),in the...