MPTP介导TRPV1抑制小鼠急性心肌梗死后细胞凋亡的保护作用

发布时间：2018-03-17 21:34

本文选题：瞬时受体电位香草酸亚型1　切入点：凋亡　出处：《重庆医科大学》2017年硕士论文　论文类型：学位论文

【摘要】：背景:在心肌缺血时,瞬时受体电位香草酸亚型1(transient receptor potential vanilloid1,TRPV1)被激活,通过传导心绞痛信号和释放神经肽,从而减轻心肌梗死后心肌细胞凋亡。目前,TRPV1抑制心肌梗死后凋亡作用的具体机制尚不清楚。近年来的研究表明,线粒体通透性转换孔(Mitochondrial permeability transitionpore,MPTP)的开放与心肌细胞缺血再灌注损伤密切相关,抑制其开放可减轻心肌缺血后心肌细胞凋亡。目的:探讨瞬时受体电位香草酸亚型1激活是否通过抑制线粒体通透性转换孔开放抑制小鼠心肌梗死后细胞凋亡。方法:首先,本研究利用左冠状动脉前降支结扎术建立了野生型(WT)和TRPV1基因敲除(TRPV1-/-)两种小鼠的心肌梗死模型,辅以环孢素A(CSA)预处理抑制MPTP开放,比较观察TRPV1、MPTP在心肌梗死中的作用。分别进行心肌损伤测定及线粒体通透性转换孔开放性测定。结果:本研究证明,TRPV1激活通过抑制MPTP开放而减少心肌细胞凋亡。心肌组织切片氯化三苯基四氮唑(TTC)染色显示,心肌缺血24 h后,TRPV1-/-小鼠的心肌梗死面积明显大于WT型小鼠,而经CSA预处理的TRPV1-/-小鼠比TRPV1-/-小鼠梗死面积明显减小。TUNEL检测心肌细胞凋亡指数(AI)揭示,WT型心肌梗死小鼠的AI明显低于TRPV1-/-心肌梗死小鼠,而CSA预处理明显降低TRPV1-/-小鼠心肌细胞的AI。Western印迹检测胱天蛋白酶3(caspase 3)、胱天蛋白酶9(caspase 9)、p53、Bcl-2/Bax比值和细胞色素C(Cyt-C)水平。结果证明,TRPV1的激活可抑制MPTP的开放,减少线粒体Cyt-C的外溢,降低caspase 9和caspase 3的表达。GENMEN光度法检测MPTP开放实验显示,激活的TRPV1明显抑制MPTP的开放。本研究证实,急性心肌梗死后的TRPV1激活可能通过抑制MPTP开放而抵抗心肌细胞凋亡,对心肌起保护作用。
[Abstract]:Background: transient receptor potential vanilloid1 TRPV1 (transient receptor potential) is activated during myocardial ischemia by signaling angina pectoris and releasing neuropeptides. At present, the mechanism of TRPV1 inhibiting apoptosis after myocardial infarction is not clear. Recent studies have shown that TRPV1 inhibits apoptosis after myocardial infarction. The opening of mitochondrial permeability transition pore Mitochondrial permeability transitionporedo (MPTP) was closely related to myocardial ischemia-reperfusion injury. To investigate whether the activation of transient receptor potential vanilic acid subtype 1 can inhibit myocardial apoptosis after myocardial ischemia by inhibiting mitochondrial permeability transition pore. Methods: firstly, we investigated whether the activation of vanillic acid subtype 1 could inhibit apoptosis after myocardial infarction in mice. In this study, two kinds of myocardial infarction models were established by left coronary artery anterior descending coronary artery ligation (WTW) and TRPV1 gene knockout TRPV1 / -) mice, which were pretreated with cyclosporine (CSA) to inhibit the opening of MPTP. The role of TRPV1 MPTP in myocardial infarction was compared. Myocardial injury and opening of mitochondrial permeability transition pore were measured respectively. Results: this study demonstrated that TRPV1 activation can reduce cardiomyocyte apoptosis by inhibiting the opening of MPTP. The muscle tissue sections were stained with TTCChloride-triphenyl tetrazolium chloride. After 24 hours of myocardial ischemia, the myocardial infarction size of TRPV1-r-mice was significantly larger than that of WT mice. However, the infarct size of TRPV1-r-mice pretreated with CSA was significantly smaller than that of TRPV1-r-mice. Tunel showed that the AI of mice with WT-type myocardial infarction was significantly lower than that of mice with TRPV1-r- myocardial infarction. CSA pretreatment significantly decreased the levels of cystatin 3, caspase 3, cystatin 9, p53, Bcl-2 / Bax and cytochrome Cyt-Con in TRPV1-r-mouse cardiomyocytes. The results showed that the activation of TRPV1 could inhibit the opening of MPTP and reduce the spillover of mitochondrial Cyt-C. Inhibition of expression of caspase 9 and caspase 3 by MPTP opening assay showed that activated TRPV1 significantly inhibited the opening of MPTP. This study confirmed that TRPV1 activation after acute myocardial infarction may resist cardiomyocyte apoptosis by inhibiting MPTP opening. Protect the myocardium.
【学位授予单位】：重庆医科大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R542.22

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