Relationgship between expression Arc and learning and memory in hippocampus of insular epilepsy rat

Abstract

Objective To research the expression of activity- regulated cytoskeletal protein in Insula Chronic Electricity igniting epilepsy rat's hippocampus,and to study the relation between Arc and electricity igniting epilepsy rat's learning and memory.Methods Adult SD rats were divided into model groups,sham operation groups,blank control groups.The model of rat insula chronic electricity igniting was built,and rats learning and memory ability were examined by way of passive avoidance test.The expression level of Arc in hippocampus was test by both immunohistochemistry and western blot,and the expression of Arc gene was test by RT- PCR.ResultThere was no significant difference of learning- remembering ability of rats between igniting group,control group and sham groups (P ＞ 0.05) in the first week after insular chronic ignition when passive avoidance test was examined.The increased learning- remembering ability appeared in the 2nd week (LT:48.87 ± 3.42 s; EN:2.75 ± 0.99) ,3rd week(LT:48.71 ± 2.77 s;EN:2.75 ± 1.15) after the ignition(P ＜0.05).After 4 weeks,there was obvious decline of learn and memory (P<0.05 ).When testing the molecular biology of Arc,there was an enhancement in expression of protein and gene for Arc in subgroup time point from 1 h,to the submit when 6 h,and to primary level when 12 h.The general tendency was to rise when one week(w),to rise fast when 2w-3w,to rise obviously slowly when 4w(P ＜0.05).There was no sense for false operation sets and blank comparison sets.Conclusion The general tendency of the expression of Arc in rat hippocampus after the chronic insular electricity ignition is consistent with the learning- remembering ability of epilepsy rats.Arc is closely associated with the learning- remember ability for epilepsy rats. Key words: Insula; Epilepsy; Activity- regulated cytoskeletal protein; Hippocampus; Learning and memory; Passive avoidance test