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目的探讨细胞外调节蛋白激酶(ERK)信号通路在蛛网膜下腔出血(SAH)后早期脑损伤及海马区神经细胞自噬中的作用。方法成年雄性Sprague-Dawley大鼠48只,随机数字表法分为假手术组(Sham组)、SAH组、SAH+二甲基亚砜(DMSO)组和SAH+U0126组,每组各12只。采用血管内穿刺法制作SAH模型。造模前30 min,SAH+U0126组经尾静脉注射U0126 0.05 mg/kg,Sham组和SAH组注射等体积生理盐水,SAH+DMSO组注射等体积DMSO,24 h后处死。干湿重法测量脑组织水含量,HE染色观察海马CA1区神经细胞形态结构,免疫组化及Western blotting检测海马区磷酸化ERK(p-ERK)及Beclin-1和LC3-Ⅱ表达水平。结果与Sham组比较,SAH组脑组织含水量增加(P<0.05),大鼠海马CA1区神经元数量明显减少(P<0.05),p-ERK及Beclin-1和LC3-Ⅱ的表达升高(P<0.05)。与SAH组相比较,SAH+U0126组脑组织含水量升高(P<0.05),海马CA1区神经元数量减少(P<0.05),p-ERK及Beclin-1、LC3-Ⅱ的表达降低(P<0.05);SAH+DMSO组各项无显著性差异(P>0.05)。结论 ERK信号通路的激活可能通过对自噬的调控减轻SAH后的早期脑损伤。
Objective To investigate the role of the extracellular regulated protein kinase (ERK) signaling pathway in early brain injury and neuronal autophagy in the hippocampus after subarachnoid hemorrhage (SAH). Methods Forty - eight male Sprague - Dawley rats were randomly divided into Sham group, SAH group, SAH + DMSO group and SAH + U0126 group, 12 in each group. SAH model was made by intravascular puncture. Thirty minutes before modeling, U0126 0.05 mg / kg was injected into tail vein of SAH + U0126 group, and equal volume of saline was injected into Sham group and SAH group. SAH + DMSO group was injected with equal volume of DMSO for 24 h. The water content of brain tissue was measured by wet-dry method. The morphological changes of hippocampal CA1 neurons were observed by HE staining. The expressions of phosphorylated ERK (p-ERK) and Beclin-1 and LC3-Ⅱ were detected by immunohistochemistry and Western blotting. Results Compared with Sham group, the water content of brain tissue in SAH group increased (P <0.05), the number of neurons in hippocampal CA1 area decreased significantly (P <0.05), the expression of p-ERK, Beclin-1 and LC3- (P <0.05). Compared with SAH group, SAH + U0126 group had higher water content in brain tissue (P <0.05), decreased number of neurons in CA1 area of hippocampus (P <0.05), decreased expression of p-ERK, Beclin-1 and LC3- P <0.05). There was no significant difference in SAH + DMSO group (P> 0.05). Conclusion The activation of ERK signaling pathway may alleviate early brain injury after SAH by regulating autophagy.