Effect Of Zinc On The Hippocampal Neurons Injury In Epileptic Mice

ObjectiveTo study the effects of zinc chelate,clioquinol,on the distribution of zinc ions,neuron morphology and number,expression of Caspase-3 in hippocampus,expression of S-100βand NSE protein in serum and cerebrospinal fluid of epileptic mice model built up by pilocarpine,and to explore the influence of zinc metabolism on the hippocampal neuron injury in epileptic mice.Methods54 CD1 mice were used in this study.Epilepsy mice model were set up by intraperitoneal injection of 300 mg/kg pilocarpine.The experiment was divided into 3 groups:mice in control group were treated with saline instead of both pilocarpine and clioquinol.Mice in epilepsy group were treated with intraperitoneal injection of saline for 7 days before the epilepsy model was set up.Mice in clioquinol group were treated with intraperitoneal injection of 10mg/kg·d clioquinol for 7 days before the epilepsy model was set up.Hippocampus,serum and cerebrospinal fluid were collected on 7^th day after epilepsy model was set up.The effect of clioquinol on the distribution of zinc in hippocampus were observed by autometallography（AMG）.The effect of clioquinol on the morphology and number of hippocampal neurons were observed by Nissl staining.Immunohistochemistry was used to check the effect of clioquinol on the expression of Caspase-3 protein in hippocampus.Enzyme-linked immunosorbent assay was used to detect the effect of clioquinol on the expression of S-100βand NSE proteins in the serum and cerebrospinal fluid.ResultsAMG showed that there were more AMG positive particles and the average optical density increased in the hippocampus of the epileptic group,compared with the control group.There were fewer AMG positive particles and the average optical density decreased in the hippocampus of the clioquinol group,compared with the epileptic group（P<0.01）.Nissl staining showed that the hippocampal neurons in the epilepsy group had obvious morphological changes,including disordered structures,unclear Nissl bodies,constriction of cytoplasm and nuclei,and the neurons number reduced significantly too.Compared with the epilepsy group,the morphology was improved and the number of hippocampal neurons increased in the clioquinol group（P<0.01）.Immunohistochemstry showed that the expression of Caspase-3 in hippocampus increased in the epilepsy group,compared with the control group.The expression of Caspase-3 protein decreased in the clioquinol group than that in the epilepsy group（P<0.01）.Enzyme-linked immunosorbent assay showed that the expression of S-100βand NSE protein in the serum and cerebrospinal fluid of the epilepsy group increased than those in the control group.The expression of S-100βand NSE protein in clioquinol group was lower than that of the epilepsy group（P<0.01）.ConclusionsEpilepsy can lead to abnormal zinc metabolism,the increased distribution of zinc,in the hippocampal neurons of mice.Epilepsy also can cause the neuron damage,morphological changes,reduced neurons,up-regulated expression of Caspase-3 in hippocampus,up-regulated expression of S-100βand NSE proteins in the serum and cerebrospinal fluid.Using zinc chelating agent can reduce the concentration of zinc,improve the neuron damage,enhance the neuron number,down-regulate the expression of Caspase-3,S-100βand NSE proteins.Zinc can affect the neuron damage in the hippocampus of epileptic mice.Reducing the distribution of zinc in hippocampus can inhibit the neuron damage in epileptic mice.