miR-199a在大鼠脑缺血耐受过程中的表达和作用

发布时间：2018-05-27 17:03

本文选题：缺血预处理 + 脑缺血耐受　；参考：《北京协和医学院》2009年博士论文

【摘要】：背景和目的：脑缺血耐受是指脑组织在经过预处理以后,获得了抵抗严重缺血的能力。HIF-1α是脑缺血耐受过程中的重要转录因子,涉及多种基因的表达调控。miRNA是近年来发现的一类21-23个核苷酸的非编码小RNA分子,在转录后水平上调控目标基因的表达。研究表明,在心肌细胞内,低氧预处理诱导HIF-1α的表达上调,且依赖于miR-199a的表达下调。本研究的目的是用小剂量3-硝基丙酸(3-NPA)预处理建立大鼠脑缺血耐受模型,探究大鼠脑缺血耐受过程中miR-199a的表达。实验方法：1、建立大鼠脑缺血耐受模型：大鼠随机分为2组,分别经腹腔注射3-NPA或生理盐水,3天后实施MCAO手术,术后第2天测定2组大鼠的脑梗死体积,并进行双侧t检验比较分析。2、检测miR-199a和HIF-1α在大鼠脑缺血耐受过程中的表达：大鼠随机分为4组,分别接受生理盐水腹腔注射、3-NPA腹腔注射、生理盐水腹腔注射+MCAO手术和3-NPA腹腔注射+MCAO手术。第4天同时处死,取脑皮质标本,用实时定量PCR法检测miR-199a和HIF-1α mRNA的水平,并进行双侧t检验比较分析。实验结果：1、3-NPA组大鼠的脑梗死体积(245.43±25.24mm3)相比对照组的(313.67±26.29mm3)下降21.76%,具有统计学显著性差异(p=0.003)。2、3-NPA组miR-199a的相对表达量(1.20±0.55)相比对照组(3.39±0.78)下降64.3%。3-NPA处理+MCAO组和MCAO组miR-199a的相对表达量较正常对照组无显著差异。各组HIF-1α mRNA水平无显著差异。实验结论：在大鼠脑缺血耐受过程中,miR-199a在脑皮质的表达水平明显下调,它与HIF-1α表达的相关性有待进一步研究。
[Abstract]:Background and objective: cerebral ischemic tolerance is the ability of brain tissue to resist severe ischemia after pretreatment. HIF-1 伪 is an important transcription factor in the process of cerebral ischemic tolerance. MiRNAs involved in the regulation of the expression of multiple genes are a class of non-coding small RNA molecules with 21-23 nucleotides found in recent years, which regulate the expression of target genes at the post-transcriptional level. The results showed that hypoxia preconditioning induced the up-regulation of HIF-1 伪 expression in cardiomyocytes and was dependent on the down-regulation of miR-199a expression. The aim of this study was to establish a rat model of cerebral ischemic tolerance by preconditioning with low dose 3-nitropropionate (3-NPA), and to investigate the expression of miR-199a during cerebral ischemia tolerance in rats. Methods: the model of cerebral ischemia tolerance was established in rats. Rats were randomly divided into two groups. The rats were treated with MCAO after intraperitoneal injection of 3-NPA or saline for 3 days. The infarct volume of the rats in the two groups was measured on the second day after operation. The expression of miR-199a and HIF-1 伪 during cerebral ischemic tolerance in rats was detected by bilateral t test. The rats were randomly divided into 4 groups and received saline intraperitoneal injection of 3-NPA intraperitoneally respectively. Normal saline intraperitoneal injection of MCAO operation and 3-NPA intraperitoneal injection of MCAO operation. On the 4th day, the cortical samples were taken and the levels of miR-199a and HIF-1 伪 mRNA were detected by real-time quantitative PCR, and the results were compared with those of bilateral t-test. Results compared with control group, the infarct volume of rats in the 1: 1 + 3-NPA group (245.43 卤25.24mm3) decreased by 21.76mm), and the relative expression of miR-199a in the MCAO group and MCAO group was significantly lower than that in the control group (1.20 卤0.55). The relative expression of miR-199a in MCAO group and MCAO group was significantly lower than that in the control group (3.39 卤0.78), and the relative expression of miR-199a in the MCAO group and MCAO group was significantly lower than that in the control group (P < 0.05), and the relative expression of miR-199a in the MCAO group and the MCAO group was significantly lower than that in the control group (P < 0.05). There was no significant difference in normal control group. There was no significant difference in the level of HIF-1 伪 mRNA in each group. Conclusion: the expression of miR-199a in cerebral cortex is down-regulated during the course of cerebral ischemia tolerance in rats. The correlation between the expression of miR-199a and the expression of HIF-1 伪 needs further study.
【学位授予单位】：北京协和医学院
【学位级别】：博士
【学位授予年份】：2009
【分类号】：R741;R3411

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