| Objective: As a chronic disorder of the brain, epilepsy could induceexcessive and repeated hyperpolarization discharge of neurons in brain, whichmay be result to transient dysfunction of the central nervous system.The recent research demonstrated that, too much Free Radical (FR)accumulating in the body may lead to chronic disorders. Theoxidative stress-mediated injury has been demonstrated toone of the important mechanisms of epilepsy. Research has proved that thereare active FR reaction in the brain of either experimental animal models orepileptic. The further increase of FR is far more than the body’s ability toremove it when epileptic seizure, which leading to the damage of neurons andmitochondria and exacerbation of epilepsy. Eliminating FR and antioxidanttherapy may provide a new therapeutic target to epilepsy.As the key factor of cell oxidative stress reaction, NF-E2-related factor2(Nrf2) regulate the expression of peroxiredoxins and phaseⅡdetoxifyingenzymes by interaction with antioxidant response element (ARE）.Nrf2-ARE signal transduction pathway play a neuroprotective role for manydiseases, such as amyotrophic lateral sclerosis (ALS)，Parkinson’s disease,cerebral hemorrhage, cerebral infarction and cerebral trauma. In this study wemainly study the mechanism that pentylenetetrazoloe (PTZ) inducing stressdamage in brain of hronic epileptic mice. In this study, epileptiform seizuregrade, behavioral change, morphological changes of hippocampus, theexpression of heme oxygenase-1(HO-1) should be observed.Method: Healthy adult male C57/B mice and Nrf2transgenic mice wererandomly selected for this experiment, provided by the Experimental AnimalCenter of Hebei Medical University, were randomly divided into four groupsafter raising a week: C57mice in the control group (C-Control group), C57 mice with epilepsy (C-PTZ group), Nrf2Knock-Off mice in the control group(N-Control group), Nrf2Knock-Off mice with epilepsy (N-PTZ group),30mice in each group.Epilepsy group were prepared by intraperitoneal administration of PTZ(32mg/kg) on13alternate days,9:00-11:30a.m. Weight the mice beforeadministration, the same volume of saline were administrated in controlgroups. Place the mice in the transparent box to observe for30minutes, recordthe maximum grade of epileptic seizure. The Racine valuation criteria was:0, no response;1, jitter like wet dog, facial tics and chewing;2, neck musclespasm (nod and/or drift);3, Side fore leg clonus;4, Bilateral fore leg clonuswith stand;5, convulsion, off balance and fell. Three consecutive records tolevel4~5indicate success in the experiment. The PTZ should injection afterthe success to induce epilepsy. Mice should be eliminated and supplemented ifdeath or unexpected to ensure the number in each group.After48hours of the last time PTZ stimulation, the hippocampus of micewere removed for the next detection. Nissl’s staining technology count thenumbers of neurons in hippocampus CAI (n=5);transmission electron microscopy observe the subcellular structure of neuronsin hippocampus CAI (n=5); Western blot measure the content of HO-1inhippocampus(n=20).Result:1Compared with C-PTZ group, the average seizures level was significantly increased (P<0.05) in N-PTZ group. Compared with C-controlgroup, the average seizures level showed no significant change (P>0.05)in N-control group.2Compared with control group, the number of neuron was significantly decreased (P<0.05) in epilespy group. Compared with C-PTZ group, the number of neuron was significantly decreased (P<0.05) in N-PTZgroup. Compared with C-control group, the number of neuron showedno significant change (P>0.05) in N-control group.3C-control group and N-control group: the subcellular structure of neurons has no abnormalities. N-PTZ group: the subcellular structure of neurons has obvious damage. C-PTZ group: the subcellular structure of neurons has slight damage.4Compared with C-control group, the expression of HO-1was decreased (P<0.05) in N-control. Compared with C-PTZ group, the expression of HO-1was decreased (P<0.05) in N-PTZ. Compared with N-control group, the expression of HO-1was decreased (P<0.05) in N-PTZ. Compared with C-control group, the expression of HO-1was increased (P<0.05) in C-PTZ.Conclusion: PTZ induced epilepsy model could well simulate thehuman hippocampus neuron damage. The average seizures level wassignificantly increased, the damage degree of neuron was significantlyincreased and the expression of HO-1was increased in N-PTZ and N-controlmice. This may be said in the course of the epilepsy, Nrf2gene may have aprotection role to hippocampal neurons. And the protection role was realizedby up-regulating the expression through activating Nrf2-ARE passageway. |
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