Starnes J W, Rumsey W L
Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia 19104.
Am J Physiol. 1988 Mar;254(3 Pt 2):H599-608. doi: 10.1152/ajpheart.1988.254.3.H599.
The effects of exercise and food restriction on hemodynamic and metabolic characteristics of the heart during aging were studied in male, retired breeder, Fischer 344 rats. At the age of 10 mo they were divided into three groups: 1) sedentary and ad libitum fed (S); 2) sedentary and food restricted by alternate-day feeding (R); and 3) exercised 20 min/day on a treadmill and ad libitum fed (E). Isolated, perfused working hearts were analyzed at 10 (S only), 18, 24, and 30 mo. Groups E and R demonstrated significant improvements (P less than 0.01) at 18 mo for cardiac output (ml.min-1.g-1), pressure work (kg.m.min-1.g-1), and efficiency (%). These performance parameters declined (P less than 0.01) after 18 mo in all groups; however, at 24 mo, E maintained higher values (P less than 0.01) for these parameters than S or R. At 30 mo, all groups were similar. Levels of high-energy phosphate compounds or lactate release were not affected by age or treatment. An age-related increase (P less than 0.05) in left ventricular hexokinase activity was observed in all groups. Activities of rate-determining enzymes of Krebs cycle or content of cytochromes were not affected by age. We conclude from this metabolic profile that energy production is not impaired in the aged Fischer 344 rat heart.
在雄性退休繁殖Fischer 344大鼠中，研究了运动和食物限制对衰老过程中心脏血流动力学和代谢特征的影响。10月龄时，将它们分为三组：1）久坐且自由进食（S组）；2）久坐且隔日喂食限制食物摄入（R组）；3）每天在跑步机上运动20分钟且自由进食（E组）。在10个月（仅S组）、18个月、24个月和30个月时，对离体灌注的工作心脏进行分析。E组和R组在18个月时的心输出量（ml·min⁻¹·g⁻¹）、压力功（kg·m·min⁻¹·g⁻¹）和效率（%）有显著改善（P<0.01）。18个月后，所有组的这些性能参数均下降（P<0.01）；然而，在24个月时，E组这些参数的值高于S组或R组（P<0.01）。在30个月时，所有组相似。高能磷酸化合物水平或乳酸释放不受年龄或处理的影响。所有组均观察到左心室己糖激酶活性随年龄增加（P<0.05）。克雷布斯循环限速酶的活性或细胞色素含量不受年龄影响。根据这种代谢情况，我们得出结论，老年Fischer 344大鼠心脏的能量产生没有受损。
