间歇有氧运动对心梗大鼠心肌间质胶原和心肌局部miR-29a/101a表征的影响

【作者】 肖丽；

【导师】 田振军；

【作者基本信息】 陕西师范大学 ， 运动生物学， 2014， 硕士

【摘要】 目的：本文拟通过间歇有氧运动对miR-29a/TGF-β1/Smad2/3和miR-101a/c-Fos/TGF-β1通路的影响及其与MI心肌纤维化的关系,探讨间歇有氧运动显著降低心肌纤维化的分子机制。方法：将48只雄性3月龄SD大鼠,随机分为4组,其中两组进行心肌梗死(MI)手术,另两组行假手术(Sham,只穿线,不结扎),4组分别为：MI安静组(MI组)12只,假手术+安静组(S组)12只,MI+间歇有氧运动组(ME组)12只,假手术+间歇有氧运动组(SE组)12只。间歇有氧运动组运动负荷参考Wisloff训练模型略加改动,即：心梗1周后,进行1周适应性跑台训练(15m/min,30min/d×5d)后,以VO2max为40%～50%热身(10m/min×10min),之后进行VO2max为85%～90%(25m/min X7min)和VO2max为50%～60%(15m/min X3min)间歇性有氧运动；之后依次交替进行,总时间为60min,5d/周,共8周。采用左冠状动脉前降支结扎法(LAD)建立大鼠MI模型；采用右颈总动脉逆行插管至左心室测定大鼠血流动力学参数,结合心电图评价大鼠心功能。采用石蜡切片Masson染色和显微图像分析系统计算心肌梗死区纤维化面积和非梗死区心肌细胞肥大程度。实时荧光定量PCR测定miR-29a和miR-101a表达,采用、Vestern Blot方法测定COL1A1、COL3A1、TGF-β1/Smad2/3和c-Fos/TGF-β1通路蛋白表征。实验结果表明：1间歇有氧运动可显著提高心肌细胞肥大程度,心肌COL1A1和COL3A1显著降低。表明,间歇有氧运动可使心肌纤维和间质胶原同步减少,显著提高心脏功能。2MI导致大鼠心肌间质胶原过度积聚,心肌纤维化,心功能下降；间歇有氧运动可降低心肌纤维化,改善受损心脏的心功能。3MI心肌胶原代谢失衡,胶原纤维过量积聚,COL1A1和COL3A1表达显著升高；间歇有氧运动可显著降低COL1A1和COL3A1表达,降低受损心脏的心肌纤维化。4间歇有氧运动可显著升高正常大鼠心肌miR-29a的表达,降低正常大鼠心肌TGF-β1/Smad2/3蛋白表达。表明间歇有氧运动升高心肌miR-29a表达在调控心肌胶原增生和心肌纤维肥大的同步发展中发挥重要作用。5间歇有氧运动可显著降低MI大鼠心肌局部TGF-β1和Smad2/3蛋白表达含量,心肌纤维化得到改善。6MI可显著降低大鼠心肌miR-29a表达,间歇有氧运动可显著升高MI大鼠心肌局部miR-29a的表达量,并通过TGF-β1/Smad2/3信号通路发挥作用,降低MI大鼠心肌纤维化。7间歇有氧运动可显著升高正常大鼠心肌miR-101a表达,降低正常大鼠心肌c-Fos和TGF-β1蛋白表达。表明间歇有氧运动升高心肌miR-101a表达在调控心肌胶原增生和心肌纤维肥大的同步发展中发挥重要作用。8间歇有氧运动可显著降低MI大鼠心肌局部c-Fcs和TGF-β1蛋白表达含量,心肌纤维化得到改善。9MI可显著降低大鼠心肌miR-101a表达,间歇有氧运动可显著升高MI大鼠心肌局部miR-101a的表达量,并通过c-Fos/TGF-β1信号通路发挥作用,降低MI大鼠心肌纤维化。结论：1间歇有氧运动可显著降低MI大鼠心肌间质胶原沉积,显著提高心脏功能；2间歇有氧运动可显著升高MI大鼠心肌miR-29a表达,降低TGF-β1/Smad2/3通路蛋白表达；3间歇有氧运动可显著升高MI大鼠心肌miR-101a表达,降低c-Fos/TGF-β1通路蛋白表达；表明,间歇有氧运动缩小心梗面积,有效提升心功能的分子机制与miR-101a/miR-29a高表达、抑制其作用位点及信号通路TGF-β1/Smad2/3和c-Fos/TGF-β1有关。更多还原

【Abstract】 Objective:This article shows that the influence of miR-29a/TGF-β1/Smad2/3and miR-101a/c-Fos/TGF-β1pathway and the relationship with MI myocardial fibrosis that intermittent aerobic exercise caaused and investigates the mechanism that intermittent aerobic exercise can degrade cardiac fibrosis.Method:The48male3-month-old SD rats were randomly divided into four groups, including two groups of myocardial infarction (MI) surgery and the other two groups that received sham surgery (Sham,wearing lines,without ligation).The four groups:MI sedentary group (MI group), sham+sedentary group (S group), MI+intermittent aerobic exercise group (ME group), sham+intermittent aerobic exercise group (SE group). The exercise load of intermittent aerobic exercise groups was based on slightly altered Wisl(?)ff training model:1wk after MI, for1wk adaptive training (15m/min,30min/d×5d),40%～50%VO2max warm-up (10m/min×10min),85%～90%VO2max (25m/min×7min) and50%～60%VO2max (15m/min×3min) intermittent aerobic exercise and turned alternately. The total time was60min,5d/wk,8w.The rat models of MI were established by adopting the left anterior descending coronary artery ligation (LAD). By using the right common carotid artery to the left ventricle in rats haemodynamics parameters were measured. Combined with ECG cardiac function in rats was evaluated.The fibrosis area of myocardial infarction and the extent of myocardial hypertrophy in non-infarcted part were calculated by paraffin section and masson staining and microscopic image analysis system. By the real-time PCR the expression of miR-29a and miR-101a were determined and by the Western Blot method pathway proteins and their characterizations of COL1A1, COL3A1, TGFβ-1/Smad2/3and c-Fos/TGFβ-1were determined.Result:1Intermittent aerobic exercise can significantly increase the degree of myocardial hypertrophy, myocardial COL1A1and COL3A1reduced significantly. It was showed that intermittent aerobic exercise can reduce myocardial fibers and interstitial collagen synchronously and improve heart function significantly. 2MI induced excessive accumulation of myocardial collagen, myocardial fibrosis and cardiac dysfunction. Intermittent aerobic exercise can reduce myocardial fibrosis and improve cardiac function.3After MI myocardial collagen was metabolic imbalance, excessive accumulation of collagen fibers, and the expression of COL1A1and COL3A1significantly increased. Intermittent aerobic exercise can significantly reduce the expression of COL1A1and COL3A1and myocardial fibrosis.4Intermittent aerobic exercise can significantly elevate expression of miR-29a and reduce protein expression of TGF-β1/Smad2/3in normal rat heart. Intermittent aerobic exercise that elevated cardiac miR-29a expression plays an important role in the regulation of synchronous development of myocardial collagen hyperplasia and myocardial fibers hypertrophy.5Intermittent aerobic exercise can significantly reduce myocardial local protein content of TGF-β1/Smad2/3in MI rats and degrade myocardial fibrosis.6MI significantly reduced expression of miR-29a in rat myocardium and intermittent aerobic exercise can significantly elevate expression of miR-29a in myocardial local of MI rat and TGF-β1/Smad2/3signaling pathway plays a role in degrading myocardial fibrosis of the MI rats.7Intermittent aerobic exercise can significantly elevate expression of miR-101a and reduce protein expression of c-Fos/TGF-β1in normal rat heart. Intermittent aerobic exercise that elevated cardiac miR-101a expression plays an important role in the regulation of synchronous development of myocardial collagen hyperplasia and of myocardial fibers hypertrophy.8Intermittent aerobic exercise can significantly reduce myocardial local protein content of c-Fos/TGF-β1in MI rats and degrade myocardial fibrosis.9MI significantly reduced expression of miR-101a in rat myocardium and intermittent aerobic exercise can significantly elevate expression of miR-101a in myocardial local of MI rat and c-Fos/TGF-β1signaling pathway plays a role in degrading myoeardial fibrosis of the MI rats.Conclusion:1Intermittent aerobic exercise can reduce myocardial interstitial collagen deposition of the MI rats and improve cardiac function significantly.2Intermittent aerobic exercise can significantly elevate expression of miR-29a in the MI rat myocardium, and reduce the protein expression of TGF-β1/Smad2/3pathway.3Intermittent aerobic exercise can significantly elevate expression of miR-101a in the MI rat myocardium, and reduce the protein expression of c-Fos/TGF-β1pathway.The molecular mechanisms that intermittent aerobic exercise reduced infarct size and improved cardiac function effectively are related with increased expression of miR-101a/miR-29a and inhibition of its action sites and TGF-β1/Smad2/3and c-Fos/TGF-β1signaling pathways.更多还原