依达拉奉对惊厥持续状态幼年大鼠海马GFAP和IL-lβ表达及细胞凋亡的影响

Effects of edravone on glial fibrillary acidic protein and interleukin-lβ expression and neuronal apoptosis in juvenile rat hippocampus after status convulsion

摘要:

目的：观察幼年大鼠惊厥持续状态（SC）后海马胶质纤维酸性蛋白（GFAP）、白介素-lβ（IL-lβ）的表达及神经细胞凋亡的变化，并探讨依达拉奉（ED）对三者的影响。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），每组 65 只，各组均按 SC 后处死时间分为 4 h、12 h、24 h、48 h、72 h 5个亚组，每组 13 只。采用氯化锂匹鲁卡品制备幼年大鼠 SC 模型。应用逆转录多聚酶链反应（RT-PCR）法检测海马GFAP mRNA 表达，免疫组化法检测海马中 GFAP、IL-lβ 蛋白表达，TUNEL 法检测神经细胞凋亡。结果：（1）免疫组化结果显示 SC 组海马中 GFAP 和 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 GFAP 和IL-1β表达明显降低，差异有统计学意义；（2）RT-PCR 法检测结果显示 GFAP 表达趋势与蛋白基本相似；（3）SC 组在惊厥 12 h 时间点海马 CA1 区 TUNEL 阳性细胞数已显著高于 NS 组，48 h 达高峰，而 ED 组 TUNEL 阳性细胞数在12～48 h 时间点均较 SC 组显著下降，但仍高于 NS 组。结论：SC 后大鼠海马 GFAP 和 IL-1β 的表达增强，ED可下调 SC 大鼠海马 GFAP 和 IL-1β 的表达，并使神经细胞凋亡减少；提示ED对 SC 引起的脑损伤可能有保护作用。

Abstract:

OBJECTIVE: To study the effects of edaravone on glial fibrillary acidic protein (GFAP) and interleukin-1β (IL-lβ) expression and neuronal apoptosis in the juvenile rat hippocampus after status convulsion (SC). METHODS: One hundred and ninety-five juvenile male Sprague-Dawley (SD) rats were randomly divided into 3 groups: normal saline control and SC with and without edaravone treatment. Each of the 3 groups was further subdivided into subgroups sacrificed at 4, 12, 24, 48 and 72 hrs after SC (n=15). The SC model was prepared using lithium-pilocarpine. The expression of GFAP and IL-lβ protein was detected with immunohistochemistry methods. The neuronal apoptosis was observed by TdT-mediated dUTP nick end labeling (TUNEL). The hippocampal GFAP mRNA expression was detected by RT-PCR. RESULTS: The value of IOD of GFAP and IL-lβ positive cells measured by immunohistochemistry in the untreated SC group increased compared with the control group. Expression of GFAP and IL-lβ protein was significantly reduced in the edaravone treated SC group compared with the untreated SC group. RT-PCR showed the expression trend of GFAP mRNA was similar to that of protein. The TUNEL positive cells in the hippocampus CA1 in the untreated SC group increased significantly 12 hrs after SC and reached a peak at 48 hrs compared with the control group. The intervention with edaravone decreased significantly TUNEL positive cells between 12-48 hrs after SC, but the number of TUNEL positive cells in the intervention group remained significantly greater than in the control group. CONCLUSIONS: The expression of GFAP and IL-lβ in the hippocampus increases after SC in rats. Edaravone may decrease the expression of GFAP and IL-1β and reduce the number of neuronal apoptosis. These results suggest that edaravone may have protective effects against brain damage caused by SC.