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

左心室机械卸荷对心肌梗死后心肌缺血耐受的影响1)结扎大鼠左冠状动脉前降支诱导心肌梗死（MI）。2) LAD结扎术后2周，行异位心脏移植，分别将供体升主动脉与受体腹主动脉吻合，肺动脉与下腔静脉吻合。3)左心室卸荷2周后，移植供心，进行Langendorff灌注。4)心脏局部缺血30分钟，再灌注60分钟。5)无负荷心肌缺血后左室发展压力高于未治疗心肌梗死心脏。心肌梗死后心肌细胞周期调节蛋白表达的变化1)8月龄大鼠结扎LAD产生心肌梗死。2)分别于LAD结扎后第3天、第1周、第2周、第4周进行心脏移植。3) real-time RT-PCR检测各组细胞周期蛋白D1、cyclin D3、Cdk2、Cdk4、Cdk6、PCNA mRNA表达水平。4) 8月龄大鼠心肌梗死后第3天和第2周，PCNA和CDK4 mRNA表达升高。衰老对细胞周期调节蛋白表达的影响1)40月龄大鼠结扎LAD产生心肌梗死。2)分别于LAD结扎后3天、1周、2周、4周进行心脏移植。3)采用实时荧光定量pcr法定量各样品中cyclin D1、cyclin D2、cyclin D3、Cdk2、Cdk4、Cdk6、PCNA mRNA的表达。4) 40月龄心肌梗死大鼠上述参数均无变化

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