Effects of aging on ischemic tolerance and a role of cell-cycle regulating proteins in ischemic myocardium

左心室机械去负荷对心肌梗死后心脏缺血耐受的影响1）结扎大鼠心脏冠状动脉左前降支（LAD）诱导心肌梗死（MI）。2）LAD结扎后2周，将供体升主动脉与受体腹主动脉、肺动脉与下腔静脉吻合进行异位心脏移植。3）LV卸载后两周，心肌缺血30分钟后再灌注60分钟，心肌缺血后左室发展压（LV developed pressure，LV development pressure）明显高于未缺血心肌（MI）。心肌梗死后细胞周期调控蛋白表达的变化1）结扎8月龄大鼠左前降支（LAD）制备心肌梗死模型，2）分别于结扎后3天、1周、2周、4周处死大鼠，留取心脏标本，检测心肌细胞周期蛋白D1、D3、Cdk 2、Cdk 4、Cdk 6、Cdk 7、Cdk 8、Cdk 4、Cdk 8、Cd 4）8月龄大鼠心肌梗死后3d和2周PCNA和CDK 4 mRNA表达均高于正常对照组，心肌梗死后3d和2周PCNA和CDK 4 mRNA表达均高于正常对照组，心肌梗死后3d和2周PCNA和CDK 4 mRNA表达均高于正常对照组结扎40月龄大鼠左前降支（LAD）制备心肌梗死模型。2）结扎后3天、1周、2周、4周分别处死大鼠，取心肌组织，用免疫组织化学方法检测心肌细胞周期蛋白D1、D2、D3、Cdk 2、Cdk 4、Cdk 6、Cdk 7、Cdk 8、Cdk 9、Cdk 10、Cdk 11、Cdk 12、Cdk 13、Cdk 14、Cdk 15、Cdk 16、Cdk 17、Cdk 18、Cdk 19、实时荧光定量RT-PCR检测心肌梗死大鼠心肌组织中PCNA和PCNA的表达。4）40月龄心肌梗死大鼠上述指标无明显变化

Effects of left ventricular (LV) Mechanical unloading on ischemic tolerance in post-MI hearts1)Myocardial infarction (MI) was Induced by ligating the left anterior descending coronary artery (LAD) of rat hearts.2)Two weeks after the LAD ligation, heterotopic heart transplantation was done by anastomosing the ascending aorta of the donor to the recipient's abdominal aorta, and the pulmonary artery to the inferior vena cava, respectively.3)Two weeks after LV unloading, donor hearts were explanted and were subjected to Langendorff perfusion.4)The hearts received 30 minutes of global ischemia and 60 Minutes of reperfusion.5)Post ischemic LV developed pressure in unloaded hearts was higher than that in untreated MI hearts.Change in expression of cell-cycle regulation proteins in post MI hearts1)MI was produced by ligating the LAD in 8-months old rats.2)The hearts were explanted after three days, one week, two weeks and four weeks after the LAD ligation respectively.3)The mRNA of cyclin D1, cyclin D3, Cdk2, Cdk4, Cdk6, and PCNA in each sample was quantified by the real-time RT-PCR.4)The mRNA of PCNA and CDK4 in 8-months old rats showed higher value three days and two weeks after MI.Effects of aging on expression of cell-cycle regulating proteins1)MI was produced by ligating the LAD fn 40-months old rats.2)The hearts were explanted after three days, one week, two weeks and four weeks after the LAD ligation.3)The mRNA of cyclin D1, cyclin D2, cyclin D3, Cdk2, Cdk4, Cdk6, and PCNA in each sample was quantified by the real-time RT-PCR.4)No change in above parameters was observed in 40-months old MI rats