小鼠蛛网膜下腔出血后海马CA1区mGluR1和ERK1/2的表达变化

目的:探讨小鼠蛛网膜下腔出血(subarachnoid hemorrhage,SAH)后代谢型谷氨酸受体1(metabotropicglutamate receptor 1,mGluR1)及细胞外信号调节激酶1/2(ERK1/2)调控神经细胞凋亡的分子机制。方法:采用非开颅血管内穿线法制备小鼠SAH模型,随机分为3组:假手术组、SAH+生理盐水(SAH+NS)组、SAH+LY367385(mGluR1抑制剂,SAH+LY367385)组,于SAH后10 min侧脑室注射生理盐水或LY367385(500 nmol/L)5μl,术后行神经功能评分。分别在SAH后6、24、48 h 3个时间点取右侧脑组织标本,逆转录-聚合酶链式反应(RT-PCR)检测各组mGluR1的表达变化,免疫印迹法(Western Blot)检测p-ERK1/2蛋白的表达,TUNEL法检测右侧海马CA1区神经细胞的凋亡。结果:与假手术组比较,SAH+NS组小鼠神经功能评分均显著降低(P<0.05),随SAH时间延长,各组小鼠mGluR1、p-ERK1/2蛋白均有不同程度增强,凋亡细胞增多(P<0.05)。与SAH+NS组比较,SAH+LY367385组小鼠神经功能评分增加,mGluR1、p-ERK1/2蛋白表达均有不同程度下调,神经细胞凋亡数目有所减少。SAH后6～48 h,mGluR1的表达与p-ERK1/2呈正相关。结论:mGluR1和ERK在SAH的发病机制中发挥了重要作用,SAH后海马内mGluR1的表达增强可通过激活ERK信号途径诱导神经细胞的凋亡。

Changes of mGluR1 extracellular signal regulated kinase 1/2 in CA1 region of the hippocampus after subarachnoid hemorrhage in mice

Objective: To study the molecular mechanism of neuronal cells apoptosis induced by activated metabotropic glutamate receptor 1(mGluR1) and extracellular signal-regulated kinase 1/2(ERK1/2) after subarachnoid hemorrhage(SAH) in mice.Methods: SAH mice model was established by endovascular perforation without opening cranium.Male mice were randomly divided into three groups: sham operation group,normal saline+SAH(SAH+NS) group and SAH+LY367385 group.10 min after SAH,5 μl of LY367385(500 nmol/L) or NS were microinjected into lateral cerebral ventricle respectively,and then neurological score was examined.At different time points(6,24,48 h) after operation,the expression change of mGluR1 was detected using RT-PCR,and Western blot assay was used to examine p-ERK1/2 expression,the number of the neuronal apoptosis in CA1 region of the hippocampus was determined by TUNEL.Results: In SAH+NS group,the neurological function scores were significantly lower(P<0.05),the expressional level of mGluR1 and p-ERK1/2 and the number of neuronal apoptosis was significantly enhanced(P<0.05) along with prolongation of SAH time.In SAH+LY367385 group,the neurological score of mice increased the expression level of mGluR1 and p-ERK1/2 was-downregulated.The number of neuronal apoptosis decreased.Conclusion: The mGluR1 and ERK1/2 may play important roles in the pathogenesis of SAH mice,the increased expression of mGluR1 in hippocampus may induce neuronal apoptosis by activation of ERK1/2 signaling after SAH.