依达拉奉预处理对惊厥持续状态幼年大鼠海马神经元保护及IL-lβ表达的影响

Protection of edravone on neurons and its effects on the expression of interleukin-lβ in juvenile rat hippocampus following status convulsion

目的观察依达拉奉预处理对幼年大鼠惊厥持续状态(SC)后脑组织海马神经元的保护作用及白介素-lβ(IL-lβ)表达的影响。方法将195只Sprague-Dawley幼年雄性大鼠随机分为生理盐水对照组(NS组)、惊厥持续状态组(SC组)和依达拉奉干预组(ED组);各组又均按时间点分为4、12、24、48、72h5个亚组。采用氯化锂-匹鲁卡品化学点燃法制备幼年大鼠SC模型。ED组于惊厥前3d予以ED腹腔注射,每天1次,连续3d。观察大鼠海马病理学改变及细胞凋亡以及IL-lβ蛋白表达情况。结果电镜显示SC组惊厥后24h海马少量神经元出现核固缩,大量内质网扩张;48h以后内质网扩张较前有所减轻,但线粒体肿胀加重。ED组各时间点神经元改变均较SC组减轻。SC组在惊厥后12h海马TUNEL阳性细胞数已显著高于NS组,48h达高峰,而ED组TUNEL阳性细胞数均较SC组显著下降,但仍高于NS组。免疫组化法示12h、24h、48h、72hSC组大鼠海马中IL-1β表达增强,与NS组比较差异有统计学意义;与SC组比较,ED组IL-1β表达明显降低,差异有统计学意义。结论ED可下调匹鲁卡品致痫大鼠海马IL-1β的表达,减轻细胞凋亡,提示ED对SC引起的脑损伤有保护作用。

Objective To study the possible protection of edaravone on neurons of the hippocampus after status convulsion （SC） and its effects on the expression of interleukin-1β （IL-lβ） in juvenile rats.Methods One hundred and ninety-five juvenile male Sprague-Dawley rats were randomly divided into three groups： SC, edaravone pretreatment and normal saline control （control group）. Each group was subdivided into five groups sacrificed at 4, 12, 24, 48 and 72 hrs after SC induction. SC model was prepared using lithium-pilocarpine. The edaravone pretreatment group received edaravone by intraperitoneal injection once daily three days before convulsion induction. Histopathologic changes in the hippocampus were viewed under a light microscope and an electron microscope. Expression of apoptosis cells was observed by TdT-mediated dUTP nick end labeling （TUNEL）. Expression of IL-lβ protein was determined by immunohistochemistry. Results Under the electron microscrope, a small quantity of neurons showed karyopycnosis and endocytoplasmic reticulum （ER） expanded remarkably 24 hrs after SC induction; at 48 hrs the ER expanding was alleviated somewhat but mitochomdria swelling was more severe. The edaravone pretreatment group showed less severe neuronal changes compared with the SC group under the microscopes. The TUNEL positive cells in the hippocampus of the SC group were significantly more than those of the control group 12 hrs, and peaked at 48 hrs after SC induction. The edaravone pretreatment group showed decreased TUNEL positive cells in the hippocampus compared with the SC group, although the positive cells were more than those in the control group between 12 and 48 hrs after SC induction. The immunohistochemistry assay demonstrated that the expression of IL-lβ in the hippocampus of the SC group increased significantly compared with that of the control group 12, 24, 48 and 72 hrs after SC induction. Edaravone pretreatment resulted in a significantly decreased IL-lβ expression in the hippocampus as compared with the SC group.Conclusions Edaravone pretreatment may decrease the IL-1β expression and neuronal apoptosis in the hippocampus. This suggests that edaravone may have protective effects against the hippocampal damage caused by SC.