大鼠离体心脏模型中雷帕霉素调节HIf1α干预缺氧预处理心肌保护作用的机制
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摘要
目的本研究组在前期研究中证实雷帕霉素会减弱缺氧预处理对原代乳鼠心肌细胞的保护作用,本研究拟在整体心脏水平验证这一现象并探讨其机制。方法建立Langendorff大鼠离体心脏模型,分别测定并分析缺血再灌注(I/R)、缺氧预处理(HPC)、雷帕霉素干预后缺氧预处理(Rapa+HPC)三组的血流动力学指标,验证雷帕霉素对缺氧预处理心肌保护效应的影响,应用qRT-PCR技术测定HIF1α与mTOR的mRNA表达水平。结果 Rapa+HPC组再灌注后30min,60min心率与I/R组差异无统计学意义,Rapa+HPC组LVDP、dp/dt虽较HPC组降低(p<0.05),但仍高于I/R组。HPC组HIF1α mRNA与mTOR mRNA水平高于I/R(16.96±1.82 vs 1.01±0.13,p<0.05;1.99±0.32 vs 1.05±0.40,p<0.05),及Rapa+HPC组(1.56±0.36,p<0.05;0.63±0.06,p<0.05)。结论缺氧预处理早期可产生心肌保护作用,促进缺血再灌注后心脏功能的恢复。雷帕霉素会减弱缺氧预处理的心肌保护效应。这一早期保护作用涉及HIF1α与mTOR表达增加,雷帕霉素可通过HIF1α与mTOR在这一过程中的表达,减弱缺氧预处理早期心肌保护作用。
Objective It's has proved rapamycin could reduce the cardioprotection effect of hypoxia preconditioning in cardiomyocytes of primary neonatal rats. In this study, we want to confirm this phenomenon in whole heart model and find out its mechanism. Methods Langendorff model was built. Hemodynamic index of I/R group, HPC group and Rapa + HPC group were measured and analyzed. Hemodynamic results were used to prove the cardioprotective effect. qRT-PCR was used to quantified HIF1α mRNA and mTOR mRNA level. Results In Langendorff model, there is no significant difference between priming Rapa+HPC for 30 min and for 60 min, the value of LVDP and dp/dt of Rapa+HPC group is a little lower than that of HPC group(p<0.05), but it still higher than that of I/R group. In HPC group, the level of HIF1α mRNA and mTOR mRNA is higher than that of I/R group(16.96±1.82 vs 1.01 ±0.13,p<0.05;1.99 ±0.32 vs 1.05 ±0.40,p<0.05), and Rapa+HPC group(1.56 ±0.36,p<0.05;0.63 ±0.06,p<0.05).Conclusion Early period of hypoxic preconditioning could produce myocardial protect effect, and promote the recovery of cardiac function after ischemia. Rapamycin can reduce effect of myocardial protect. This effect refers to the increase of HIF1αand mTOR,rapamycin can express through HIF1α and mTOR, to reach the effect of decreasing of myocardial protect in the period of pretreatment of ischemia.
Objective It's has proved rapamycin could reduce the cardioprotection effect of hypoxia preconditioning in cardiomyocytes of primary neonatal rats. In this study, we want to confirm this phenomenon in whole heart model and find out its mechanism. Methods Langendorff model was built. Hemodynamic index of I/R group, HPC group and Rapa + HPC group were measured and analyzed. Hemodynamic results were used to prove the cardioprotective effect. qRT-PCR was used to quantified HIF1α mRNA and mTOR mRNA level. Results In Langendorff model, there is no significant difference between priming Rapa+HPC for 30 min and for 60 min, the value of LVDP and dp/dt of Rapa+HPC group is a little lower than that of HPC group(p<0.05), but it still higher than that of I/R group. In HPC group, the level of HIF1α mRNA and mTOR mRNA is higher than that of I/R group(16.96±1.82 vs 1.01 ±0.13,p<0.05;1.99 ±0.32 vs 1.05 ±0.40,p<0.05), and Rapa+HPC group(1.56 ±0.36,p<0.05;0.63 ±0.06,p<0.05).Conclusion Early period of hypoxic preconditioning could produce myocardial protect effect, and promote the recovery of cardiac function after ischemia. Rapamycin can reduce effect of myocardial protect. This effect refers to the increase of HIF1αand mTOR,rapamycin can express through HIF1α and mTOR, to reach the effect of decreasing of myocardial protect in the period of pretreatment of ischemia.
引文
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[9]Toschi A,Lee E,Gadir N,et al.Differential dependence of hypoxia-inducible factors 1 alpha and 2 alpha on mTORC1 and mTORC2[J].J Biol Chem,2008,283:34495-34499.
[2]Mei DA,Nithipatikom K,Lasley RD,et al.Myocardial preconditioning produced by ischemia,hypoxia,and a KATP channel opener:effects on interstitial adenosine in dogs[J].J Mol Cell Cardiol.1998,30:(6)1225-1236.
[3]伊利亚尔·买买提力,俞瑾,郭海,郑宏.mTOR在缺氧预处理减轻乳鼠离体心肌细胞氧糖缺失/复氧复糖损伤中的作用[J].中华麻醉学杂志,2014,34(3),363-365.
[4]郑宏,马明,任新英,陈春玲,王江.实用新型技术专利,双体外循环装置,专利号:201220570855.4,
[5]Buss SJ,Muenz S,Riffel JH,et al.Beneficial effects of Mammalian target of rapamycin inhibition on left ventricular remodeling after myocardial infarction[J].J Am Coll Cardiol,2009,54:2435-2446.
[6]Lajoie C,El-Helou V,Proulx C,et al.Infarct size is increased in female post-MI rats treated with rapamycin[J].Can J Physiol Pharmacol.2009Jun,87(6):460-70.
[7]Zheng H,Ma HP,Wang J,et al.Preoperative HO-1 levels as prognostic factor for adverse cardiac events in elder patients undergoing non-cardiac surgery.PLo S One.2013,8(3):e58567.doi:10.1371/journal.pone.0058567.Epub 2013 Mar 19.
[8]Raphael J,Zuo Z,Abedat S,et al.Isoflurane preconditioning decreases myocardial infarction in rabbits via up-regulation of hypoxia inducible factor 1 that is mediated by mammalian target of rapamycin[J].Anesthesiology,2008,108:415-425.
[9]Toschi A,Lee E,Gadir N,et al.Differential dependence of hypoxia-inducible factors 1 alpha and 2 alpha on mTORC1 and mTORC2[J].J Biol Chem,2008,283:34495-34499.