肌苷对大鼠脑缺血再灌注后血管内皮生长因子表达的影响

背景肌苷参与机体多方面的代谢过程,对缺血性脑损伤具有一定的保护作用,但其机制还没有彻底阐明.目的研究肌苷对大鼠脑缺血再灌注后血管内皮生长因子(vascular endothelial growthfactor,VEGF)表达的影响,探讨肌苷的神经保护作用机制.设计随机对照的实验研究.地点和材料本实验在青岛大学医学院脑血管病研究所和山东省脑血管病防治重点实验室完成.成年健康雌性SD大鼠68只,体质量230～270 g,清洁级,由中国科学院上海实验动物中心提供.干预措施成年健康雌性SD大鼠68只,应用线栓法建立SD大鼠大脑中动脉阻塞(MCAO)再灌注模型,随机分为治疗组32只和对照组32只,每组再随机分为缺血1.5 h再灌流2,6,12,24 h,2,3,7,14 d组(n=4),另外4只作假手术组.应用免疫组织化学方法检测脑缺血再灌流后脑组织VEGF的表达.结果假手术组脑组织未见VEGF阳性表达.对照组在皮层区和纹状体区VEGF在脑缺血再灌注2 h开始表达,12 h达高峰,持续24 h,随即迅速降低.VEGF阳性细胞主要位于Ⅱ,Ⅲ,Ⅳ层神经元和血管内皮细胞,尤其神经细胞核周细胞浆和树突染色最深.肌苷治疗组VEGF表达于缺血再灌注2 h～2 d较对照组显著增高,经统计学处理,差异有非常显著性意义(t=3.78～22.62,P＜0.01).结论肌苷可上调脑缺血再灌注后VEGF的表达,可能是其缺血后神经保护作用的机制之一.

Effect of inosine on expression of vascular endothelial growth factor following local cerebral ischemic reperfusion in rats

BACKGROUND: Inosine takes part in a lot of metabolic processes and has a protective effect on cerebral ischemic injury, but its mechanism is not known thoroughly.OBJECTIVE: To study the effect of inosine on expression of vascular endothelial growth factor(VEGF) in the cerebral tissue after cerebral ischemia reperfusion in rats, and to explore the neuroprotective mechanism of inosine.DESIGN: A randomized controlled basic research.SETTING and MATERIALS: This experiment was carried out at the Institute of Cerebrovascular Diseases, College of Medicine, Qingdao University and the Key Laboratory of Cerebrovascular Diseases of Shandong Province.Sixty-eight adult healthy female SD rats, weighting 230- 270 g, clearing grade, were purchased from Shanghai Experimental Animal Center of the Chinese Academy of Science.INTERVENTION: The models of ischemia/reperfusion in SD rats were established by middle cerebral artery occlusion(MCAO) with a nylon monofilament suture. The rats were randomly divided into the treatment groups 32cases and the control group 32 cases. Each group was divided into eight subgroups, which consisted of 4 rats at 2 hours, 6 hours, 12 hours, 24 hours, 2days , 3 days, 7 days and 14 days after reperfusion of MACO. The other 4cases served as sham-operated group. Immunohistochemical technique was used to investigate the dynamic changes of VEGF in cerebral tissue.RESULTS: There was no expression of VEGF in cerebral tissue of sham-operated group. The expression of VEGF occurred at 2 hours, peaked at 12-24 hours after reperfusion and then decreased rapidly in cortex and striatum in the control group. VEGF expressed mainly in neurons and endothelial cells in Ⅱ, Ⅲ, Ⅳ layers in cortex, especially colored mostly in the perinucleus cytoplasm and dendrites of neurons. In the treatment group, the level of VEGF expression was significantly higher than that in the control group at reperfusion 2 hours - 2 days( t = 3.78 - 22.62, P ＜ 0.01 ).CONCLUSIONS: These results indicated that Inosine could protect cerebral tissue against hypoxic-ischemic injury after reperfusion of focal cerebral ischemia, whose role might be reflected by increasing the expression of VEGF.