LY367385通过抑制细胞外信号调节激酶途径减轻小鼠脑血管痉挛后神经细胞凋亡

LY367385 attenuates neuronal apoptosis after cerebral vasospasm in mice by inhibiting extracellular signal-regulated kinase pathway

目的:探讨代谢型谷氨酸受体1(mGluR1)选择性拮抗剂LY367385对脑血管痉挛(CVS)后神经细胞凋亡的影响及细胞外信号调节激酶1/2(ERKl/2)途径的作用。方法:采用非开颅血管内线栓法制备小鼠蛛网膜下腔出血(SAH)并CVS模型,随机分为3组:假手术组、模型对照组和mGluR1拮抗剂LY367385组,于SAH后10 min侧脑室注射生理盐水或LY367385(500 nmol)5μL,术后行神经功能评分。分别在SAH后6、24和48 h 3个时点取右侧脑组织标本,在光镜和电镜下观察脑组织病理变化,采用逆转录-聚合酶链式反应检测各组mGluR1mRNA的表达变化;蛋白免疫印迹法检测mGluR1和p-ERK1/2蛋白的表达;用TUNEL法检测神经细胞凋亡情况。结果:与假手术组比较,模型组小鼠神经功能评分显著降低,随CVS时间延长,各组小鼠mGluR1 mRNA、mGluR1和p-ERK1/2蛋白均有不同程度增强,凋亡细胞增多,神经细胞出现变性坏死、神经轴索变性断裂。与模型组比较,拮抗剂组小鼠神经功能评分增加,mGluR1 mRNA、mGluR1和p-ERK1/2蛋白表达均有不同程度下调,神经细胞凋亡数目减少,脑组织形态学和超微结构损伤减轻。结论:(1)CVS后mGluR1的表达增强可通过激活ERK信号途径诱导神经细胞凋亡。(2)mGluR1选择性拮抗剂LY367385对CVS损伤具有拮抗作用。

AIM： To investigate the effects of LY367385, a selective antagonist of metabotropie glutamate re- ceptor 1 （ mGluR1 ）, on the apeptosis of neuron, and the role of extracellular signal - regulated kinase 1/2 （ERK1/2） sig- nal pathway after cerebral vasospasm （CVS） in mice. METHODS ： The model of subarachnoid hemorrhage （SAH） in mice was established by endovascular perforation without opening cranium. Male ICR mice were randomly divided into 3 groups ： sham operation group, NS ＋ SAH group and LY367385 ＋ SAH group. Ten minutes after SAH, 5 μL of LY367385 or NS was microinjected into lateral cerebral ventricle, and then the neurological scores of the animals were examined. At different time points （6 h, 24 h, 48 h） after operation, the pathological changes in the brain tissues were observed under light and electron microscopes. The mRNA expression of mGluR1 was detected using RT - PCR, and Western blotting was used to examine the protein levels of mGluR1 and p - ERK1/2. Apeptotie cell number was determined by TdT - mediated dUTP nick end labeling （TUNEL） method. RESULTS： In SAH ＋ NS group, the scores of neurological function were sig- nificantly lower, while the mGluR1 mRNA, mGluR1 and p - ERK1/2 proteins and the number of apeptotic cells were sig- nificantly higher than those in sham operation group. Some neurons displayed histopathological changes of necrosis, myelin sheath internalization and disconnection. LY367385 decreased the mRNA expression of mGluR1 and protein levels of mGluR1 and ERK1/2. The neuronal apoptosis, heurological score and the ultrastructural changes were also improved. CONCLUSION： The increased expression of mGluR1 in hippocampus may induce apeptosis by activation of ERK1/2 sig- naling after CVS. LY367385 exerts good therapeutic effect on severe CVS.