Abstract: Objective  To evaluate the protective effects of endoplasmic reticulum stress preconditioning induced by 2-deoxyglucose (2-DG) on hippocampal neurons of rats with status epilepticus (SE) and the possible mechanism.  Methods  Ninety Sprague-Dawley (SD) rats were randomly enrolled into preconditioning group (N = 30), SE group (N = 30) and control group (N = 30). Each group was divided into 6 subsets (N = 5) according to six time points (before seizure, 6 h, 12 h, 1 d, 2 d and 7 d after seizure). The preconditioning group was administered 2-DG intraperitoneally with a dose of 150 mg/kg for 7 days, and the lithium-pilocarpine induced SE rat model was established on both preconditioning group and SE group. The rats were sacrificed at the above six time points, and the brains were removed to make paraffin sections. Nissl staining was performed by toluidine blue to evaluate the hippocampal neuronal damage after seizure, and the number of survival neurons in hippocampal CA1 and CA3 regions of the rats were counted. Immunohistochemical staining was performed to detect the expressions of glucose regulated protein 78 (GRP78) and X-box binding protein 1 (XBP-1) in hippocampal CA3 region of the rats.  Results  The number of survival neurons in preconditioning group was much more than that in SE group at 7 d after seizure (t = 5.353, P = 0.000), and was more obvious in CA1 region. There was no significant hippocampal neuronal damage in control group. The expressions of GRP78 and XBP-1 in CA3 region of hippocampus in SE group at 6 h after seizure were significantly higher than that in control group (P = 0.000), and then kept increasing until reaching the peak at 2 d (P = 0.000, for all). The expressions of GRP78 and XBP-1 in hippocampal CA3 region in preconditioning group were significantly higher than that in control group before seizure (P = 0.000, for all). The level of GRP78 maintained the highest at 24 h and 2 d after seizure (P = 0.000, for all), while the XBP-1 level reached the peak at 24 h after seizure (P = 0.000). The expressions of GRP78 and XBP-1 in hippocampal CA3 region in preconditioning group were significantly higher than that in SE group at before seizure, 6, 12, 24 h after seizure (P = 0.000, for all), while there was no significant difference at 2, 7 d after seizure (P > 0.05).  Conclusions  Endoplasmic reticulum stress preconditioning could protect hippocampal neurons from damage in rats with status epilepticus, in which the XBP-1-GRP78 signal pathway may be an important mechanism.

Key words: Status epilepticus, Endoplasmic reticulum, Hippocampus, Disease models, animal

摘要： 目的 探讨2-脱氧葡萄糖诱导内质网应激预适应对癫痫持续状态大鼠海马神经元的保护作用及其可能机制。方法 采用2-脱氧葡萄糖连续腹腔注射诱导内质网应激，并在此基础上制备氯化锂-匹罗卡品癫痫持续状态大鼠模型。Nissl 染色观察癫痫持续状态后海马神经元损伤情况、计数海马CA1 和CA3 区存活神经元数目；免疫组织化学检测海马CA3 区内质网应激标志物葡萄糖调节蛋白78（GRP78）和X 盒结合蛋白1（XBP-1）表达变化。结果 与癫痫持续状态组相比，癫痫持续状态后第7天时内质网应激预适应组大鼠海马存活神经元数目增加，以CA1区显著（t = 5.353，P = 0.000）。癫痫持续状态组大鼠发作后6 h，海马CA3区GRP78和XBP-1表达水平升高且高于对照组（均P = 0.000），于发作第2天达峰值水平（均P = 0.000）；内质网应激预适应组大鼠发作前海马CA3 区GRP78 和XBP-1 表达即高于对照组（均P = 0.000），GRP78 在发作后24 h和2 d时维持在峰值水平（均P = 0.000），XBP-1在发作后24 h达峰值水平（P = 0.000）；内质网应激预适应组大鼠海马CA3 区GRP78 和XBP-1 表达在癫痫持续状态前，以及癫痫持续状态后6、12、24 h 均高于癫痫持续状态组（均P = 0.000），至第2 和7 天时与癫痫持续状态组之间差异无统计学意义（P > 0.05）。结论 经2-脱氧葡萄糖诱导的内质网应激预适应对癫痫持续状态大鼠海马神经元具有保护作用，而XBP-1-GRP78信号转导通路的活化可能是其机制之一。

关键词: 癫痫持续状态, 内质网, 海马, 疾病模型, 动物