离子型谷氨酸受体拮抗剂MK-801浓度与全脑缺血再灌注大鼠海马内源性神经干细胞的增殖

摘要

背景:脑缺血再灌注后,过度释放的兴奋性氨基酸可通过N-甲基-D-天冬氨酸(NMDA)受体激活内源性神经干细胞,促使其增殖、分化,修复神经细胞,但同时也导致细胞内钙离子超载,引起神经细胞的损伤.目的:观察NMDA受体拮抗剂MK-801浓度对脑缺血再灌注大鼠海马内源性神经干细胞增殖的影响.方法:SD大鼠随机分为正常对照组、手术对照组及MK-801 0.2,0.4,0.6,0.8,1.0,1.2 mg/kg组.除正常对照组外,大鼠首先进行侧脑室插管,3 d后进行4条血管阻断方法制备大鼠全脑缺血再灌注模型.在模型制作前30 min按照不同浓度侧脑室注射MK-801.正常对照组和手术对照组侧脑室注射同剂量的生理盐水.免疫组织化学、RT-PCR技术检测各组脑海马nestin阳性细胞及其mRNA表达.结果与结论:MK-801浓度在0.8 mg/kg以下时,用药组大鼠脑海马nestin mRNA及蛋白的表达与手术对照组差异无显著性意义(P > 0.05),呈现高表达;当MK-801浓度达到0.8 mg/kg时,与手术对照组相比,用药组大鼠脑海马nestin基因及蛋白的表达明显下降(P < 0.05),并随浓度的增高呈递减趋势.提示MK-801在浓度为0.6 mg/kg时,即可抑制钙超载保护神经元,又有良好的刺激神经干细胞增殖作用.%BACKGROUND: After cerebral ischemia-reperfusion, excessive excitatory amino acids can activate endogenous neural stem cells (NSCs) through N-methyl-D-aspartic acid (NMDA) receptor and can repair nerve cells by the proliferation and differentiation of endogenous NSCs but damage nerve cells by intracellular calcium overload at the same time.OBJECTIVE: To study the effect of NMDA receptor antagonist MK-801 on the proliferation of endogenous NSCs of global cerebral ischemia-reperfusion rat hippocampus.METHODS: The SD rats were divided into control group, operation group and different concentrations of MK-801 group (0.2, 0.4, 0.6, 0.8,1.0, 1.2 mg/kg). The rats were first treated with lateral ventricle intubation, and 3 days later, four-vessel occlusion was used to establish global cerebral ischemia-reperfusion model, except the control group. Different doses of MK-801 were intracerebrally ventricularly injected at 30 minutes before cerebral ischemia. The same concentration of normal saline was used in control group and operation group. Immunohistochemistry and RT-PCR technique were used to detect nestin positive cells and mRNA level expression.RESULTS AND CONCLUSION: When the concentration of MK-801 was under 0.8 mg/kg, the protein and mRNA expression of nestin was high and there was no difference between MK-801 group and operation group (P > 0.05). When the concentration of MK-801 was equal to 0.8 mg/kg, the expression of nestin gene and protein was decreased significantly with MK-801 increasing (P < 0.05). MK-801 can not only inhibit calcium overload but also has good effect on stimulating neural stem cell proliferation at the concentration of 0.6 mg/kg.