Effect Of Vagus Nerve Stimulation On Hippocampal GFAP Of Astrocytes In A Rat Model Of Epilepsy Kindled By Kainic Acid

ObjectivesThe epileptic model was made by using microinjection of KA into the lateralventricle of rats. The present study analyzed the effects of VNS on epilepsyprevention and hippocampal expression of glial fibrillary. To investigateastrocytes action on hippocampus of rats, to provide the evidence for themechanism of VNS in inhibiting epilepsy.MethodsForty-eight mature Sprag-Dawley rats were equally divided into four groups:control group、VNS group、 KA group and VNS+KA group. The epileptic modelwas made using microinjection of KA(0.5μg/μl,3μl) into the lateral ventricle ofrats. To observe the behavioral changes of rats actions and ECoG after VNS.The immunohistochemistry and western blot was used to observe c-fos andGFAP of astrocytes in hippocampus after VNS.ResultsThe injection of KA triggered epileptic motor seizures, includingimmobilization，staring，facial and jaw clonus, beard rearing，and falling，followed by recurrent generalized convulsive seizures that the Racine score Ⅳ~Ⅴ. A notable decrease appeared in action in VNS+KA group compared withKA group. There was α wave or β wave，which are normal waves， each lead inthe VNS group and control group.In contrast， the injection of KA triggeredepileptic discharges，such as spike wave，sharp wave，and spike(sharp)-slowwave at the cortices. A notable decrease appeared in ECoG in VNS+KA group compared with KA group. The obvious increase of c-fos and GFAPimmunoreactivity was detected at KA group compared with control group(P<0.01), A notable decrease of c-fos and GFAP appeared in VNS+KA groupcompared with KA group (P<0.01). The expression of GFAP of astrocytes inhippocampus did not change obviously. The injection of KA triggered epilepticmotor seizures.ConclusionsThe epileptic model could be made by using microinjection of KA into thelateral ventricle of rats.VNS can effectively control the epileptic seizures,decrease expression of GFAP in astrocyte and c-fos after VNS, which suggestsastrocyte plays a key role in anti-epilepsy effect.