背景:白细胞介素1受体拮抗因子能显著减轻神经元的损伤具有神经保护作用.谷氨酸通过激活多种谷氨酸受体导致兴奋毒性作用,同时也可以通过其某些受体发挥神经保护作用.但二者在脑缺血再灌注过程中的联系仍不十分明了.目的:探讨脑缺血再灌注损伤过程中白细胞介素1受体拮抗因子对海马神经元的神经保护作用以及白细胞介素1受体拮抗因子与代谢性谷氨酸受体5之间的关系.设计:完全随机对照实验.单位:中国科学院武汉物理与数学研究所波谱与原子分子物理国家重点实验室,江汉大学医学与生命科学学院.材料:实验于2004-05/2005-01在中国科学院武汉物理与数学研究所波谱学与原子分子物理国家重点实验室完成.选择正常健康纯化Wistar大鼠32只.方法:32只大鼠按单纯随机抽样的方法分为正常组、假手术组、生理盐水组和实验组.正常组大鼠不做任何处理,假手术组大鼠仅在颈部前后方做组织分离、椎动脉暴露、颈总动脉游离手术,不结扎和夹闭双侧椎动脉和颈总动脉;生理盐水组大鼠椎动脉用电烧灼的方法永久性阻断,颈总动脉暂时性(20 min)夹闭,夹闭动脉期间内将2 μL生理盐水按0.4 μL/min的速度注入大鼠一侧(右侧)侧脑室,拔针前滞针5 min,然后松开颈总动脉的动脉夹再灌注2 h;实验组大鼠操作过程相同,仅将生理盐水换成等量的人重组白细胞介素1受体拮抗剂.然后采用苏木精-伊红染色方法对大鼠皮质区域的病理变化进行观察,免疫组织化学方法对海马神经元代谢性谷氨酸受体5免疫反应性进行观察.主要观察指标:①各组大鼠脑皮质、海马的基本病理学变化.②各组大鼠脑缺血敏感区海马神经元代谢性谷氨酸受体5免疫反应变化.结果:实验组和生理盐水组各有1只在进行缺血再灌注的过程中诱发惊厥被弃用,其余30只大鼠进入结果分析.①各组大鼠脑皮质、海马的基本病理学变化:正常组、假手术组大鼠差异不明显,生理盐水组和实验组大鼠皮质、海马神经元变性,细胞周围水肿,神经元深染、核固缩或破裂.实验组神经元变性及水肿程度明显降低,深染、核固缩或破裂的神经元明显减少.②各组大鼠脑缺血敏感区海马神经元代谢性谷氨酸受体5免疫反应变化(用平均吸光度值表示):正常组与假手术组大鼠海马CA1,CA3区神经元代谢性谷氨酸受体5免疫反应呈强阳性[CA1区:(0.54±0.12),(0.54±0.05);CA3区:(0.57±0.02),(0.58±0.08),(P＞0.05)].生理盐水组、实验组大鼠海马CA1,CA3区神经元免疫反应较正常组和假手术组明显减弱[CA1区:(0.30±0.03),(0.40±0.04);CA3区:(0.30±0.04),(0.42±0.06),(P＜0.01)],实验组较生理盐水组明显增强(P＜0.05).结论:白细胞介素1受体拮抗因子和代谢性谷氨酸受体5均参与大鼠脑缺血再灌注损伤的病理生理过程;白细胞介素1受体拮抗因子在大鼠脑缺血再灌注损伤的病理过程中,可能调节脑海马CA1,CA3区神经元的代谢性谷氨酸受体5的表达,实现其对海马的营养和保护作用;白细胞介素1家族中除了白细胞介素1受体拮抗因子以外,还存在其他的调节因素对神经元的代谢性谷氨酸受体5的表达进行调控.%BACKGROUND: Interleukin-1 receptor antagonist can relieve damage of neuron and protect nerve. Aminoglutaric acid can induce exitotoxicity through activating some kinds of aminoglutaric acid receptor, at the same time, can protect nerve through some receptors. But the relationship between them was unclear during the process of cerebral ischemia reperfusion.OBJECTIVE: To investigate the effect of neuroprotective actions of interleukin-1 receptor antagonist on hippocampal neurons, and the relationship between interleukin-1 receptor antagonist and metabotropic glutamate receptor 5 within the process of cerebral ischemic reperfusion injury.DESIGN: Completed randomized controlled study.SETTING: State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences; School of Medicine & Life, Jianghan University.MATERIALS: The experiment was performed at State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Science from May 2004 to January 2005. Totally 32 well-being pure breed male Wistar rats were selected.METHODS: Totally 32 rats were divided into four groups by method of the simple random sampling: normal group (n=8) received no surgical treatment, sham operated group (n=8) subjected to only dorsal and ventral neck midline incisions and gently dissection of the bilateral common carotid arteries free of surrounding nerve fibers without occlusion of the both vertebral arteries and common carotid arteries, saline group (n=8) suffered from the permanently occlusion of the both vertebral arteries by electrocauterization and transient (20 minutes) occlusion of bilateral common carotid arteries respectively, and received the treatment of a 2 μL normal saline injection into right lateral ventricle at the rate of 0.4 μL/minute following a needle withdrawal within 5 minutes, and experiment group (n=8) offered the same procedure of the saline group but for that the equivalent amount of rhIL-1ra took the place of normal saline into the lateral ventricle. Hematein-eosin staining was applied to observe pathological changes and immunohistochemistry (ABC) was used to survey the IR of mGluR5 varieties of the hippocampal neurons.MAIN OUTCOME MEASURES: ① Basic pathological changes of hip pocampus and cerebral cortex; ② mGluR5 immunoreactivity (IR) of hippocampus, the sensitive area to cerebral ischemia.RESULTS: Two rats were excluded from the experiment on account of their convulsion during reperfusion (one of the experiment group, another of the saline group), data of 30 rats was entered final analysis. ①Basic pathological changes of hippocampus and cerebral cortex: The Hemateineosin (H.E) staining showed that there is little pathological discrepancy between the normal group and the sham operated group, apparent neuronal degeneration such as peripheral edema around neurons, pyknosis, karyorrhexis and so onin the hippocampus and cortex of the rats of the saline group compared with those of the previous groups, and also the pronounced lower degree of neuronal degenerationin the rats of the experiment group.② mGluR5 immunoreactivity (IR) of hippocampus, the sensitive area to cerebral ischemia (absorbency): The immunohistochemistry presented that the mGluR5 immunoreactivity (IR) of CA1, CA3 areas of the normal group and sham group rats was strong positive (CA1: 0.54±0.12, 0.54±0.05; CA3:0.57±0.02, 0.58±0.08;P ＞ 0.05) Compared with of the normal group and sham group, the mGluR5 IR of the saline and the experiment groups reduced apparently (CA1: 0.30±0.03, 0.40±0.04; CA3: 0.30±0.04, 0.42±0.06;P ＜ 0.01), but the mGluR5 IR of the experiment group was quite stronger than that of the saline one (P ＜ 0.05).CONCLUSION: IL-1ra, one member of the Interleukin-1 family (system)of the cytokines, and mGluR5, one subtype of the metabotropic glutamate receptors were both involved in the pathophysiological process of the global cerebral ischemia reperfusion injury of the rat. Also, as the antagonist of the proimflammatory medium intetleukin-1 receptor, IL-1ra may show neuroprotection by affecting the mGluR5 expression of the CA1 and CA3 areas of the rat hippocampus within the process of cerebral ischemic reperfusion injury. Furthermore, here it demonstrated that besides IL-1ra, other factors might regulate the expression of mGluR5.
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