| Epilepsy is a common neurological disorde, It affecting more than9million patients in china. About one quarter of patients suffer with intractable epilepsy. Temporal lobe epilepsy (TLE) presents the most prevalent refractory epilepsy and its pathogenesis has not yet been fully elucidated. The antiepileptic drugs (AEDs) and surgical therapy is often difficult to obtain significant effects, recurrent seizures brings a heavy burden to patients, family and social. The alteration of behavior and the hippocampal neuronal injury in lithium-pilocarpin induced seizures in rats is similar to that in TLE patients, so lithium-pilocarpin induced seizures have been one of the most frequently used models to research status epilepticus (SE) and TLE. However, the molecular mechanisms that SE or repeated seizures cause neuronal damage are still not very clear. It is very important to further explore the pathogenesis of epilepsy and search for new drugs with neuroprotective effects.Salubrinal, a new selective phosphatase inhibitor that selectively inhibits dephosphorylation of the eukaryotic translation initiation factor2subunit α(elf2α), has been shown to protect neurons from stress-induced damage. Phosphorylation of elf2α is a highly conserved point of convergence adapting eukaryotic cells to various stress response pathways, such as hypoxia and oxidative stress. Phosphorylized elf2α (P-elf2α) mediated autophagy is recognized as a protective mechanism against various cellular stresses, and it has been uncovered in neurological disease, including Huntington disease and Parkinson’s disease.However, whether Salubrinal exerts biological effects on hippocampal neuronal injury in lithium-pilocarpin induced seizures is unknown. At present study, we observe the pathology of hippocampal neurons damage in ithium-pilocarpin induced seizures; To study the effects of Salubrinal on neuronal ultrastructure of hippocampus in rats. Further to investigate the effect of Salubrinal on elf2a and the autophagy-related protein in hippocampus, and to explored the anti epileptic effeets of Salubrinal and its potential mechanisms. ObjectiveTo investigate the alteration of behavior in lithium-pilocarpine induced seizures in rats, and to explore the pathology changes of hippocampus.MethodsAdult male Wistar rats were given lithium-pilocarpine intraperitoneally to induce SE. Rats were monitored by video recordings to assure the change of behavior. Seizures were allowed to last for60min and then were terminated by administration of diazepam. The pathological changes were researched with HE and Nissl at24h after SE.Results1. According to Racine, the rats showing stage IV or V convulsive seizures were considered to develop SE successfully.86.3%rats were induced to develop SE after administration of lithium-pilocarpine. The time from pilocarpine injection to the first onset of SE was43.35±7.1min, and the death rate within24h was22.7%.2. HE and Nissl staining showed the neuronal damage in hippocampal CA1and CA3regions at24h after SE onset. The surviving neurons showed round and palely stained nuclei. At the same time, the dead neurons showed pyknotic nuclei and shrunken plasma body.ConclusionsLithium-pilocarpine could induce SE according to the alteration of behavior. Lithium-pilocarpine induced SE caused hippocampal neuronal injury in rats. ObjectiveTo investigate the effect of Salubrinal on hippocampal neurons after seizures induced by pilocarpine, and to study the effect of Salubrinal on phosphorylation of eIF2α and autophagy-related protein in hippocampus, further explore the mechanism of the neuroprotective effect of Salubrinal on SE rats.MethodsAdult male Wistar rats were randomly divided into4groups for treatment:control, pilocarpine, pilocarpine+Salubrinal, pilocarpine+saline. We performed Nissl staining at24h after SE onset to examine the number of surviving neurons in CA1and CA3regions of hippocampus in rats. The time course expression of elf2a, P-elf2a, LC3Ⅱ and LC3Ⅰ in hippocampus of SE rats were detected by Western blot.Results1. There is no significant difference between Salubrinal injection group and with pilocarpine alone group in the latency period and the percentage of animals reaching stageⅣ, the mortality due to SE at24h of Salubrinal injection group was considerably lower than with pilocarpine alone group (p<0.05). Control animals did not exhibit any behavioral seizure activity.2. Nissl staining to examine the neuronal loss in hippocampal CA1and CA3regions after pilocarpine-induced seizures revealed that seizures led to severe cell death at24h after seizures. The number of surviving neurons was decreased significantly as compared with control (p<0.05). Moreover, neuronal cell death subfield24h after SE was significantly attenuated by pretreatment with Salubrinal (p<0.05).3. Western blot analysis showed that P-elf2α was markedly increased at30min after SE onset, then decreased rapidly (p<0.05), The ratio of LC3II to LC3I was significantly increased at SE1h-2h, SE1h-6h, SE1h-16h, SE1h-24h, and SE1h-72h, peaking at24h (p <0.05).4. Salubrinal significantly reinforced the increased expression of P-elf2a at30min after SE onset (p<0.05). As well, the expression of LC3Ⅱ and the ratio of LC3Ⅱ to LC3Ⅰ was higher with Salubrinal injection group than with pilocarpine alone group (p<0.05).ConclusionsOur results implied that Salubrinal had neuro protective effects, and the mechanism maybe related to promoting phosphorylation of eIF2α and the stimulating of autophagy via P-elf2α. Salubrinal may could be a potential benefit treatment for the hippocampal neuron demise caused by piloearpine-induced seizures. P-elf2α and subsequent activation of autophagy may represent a novel treatment targets for epilepsy. |
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