Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida 32611, USA.
J Appl Physiol (1985). 2012 Dec 1;113(11):1699-708. doi: 10.1152/japplphysiol.01025.2012. Epub 2012 Oct 4.
With old age, blood flow to the high-oxidative red skeletal muscle is reduced and blood flow to the low-oxidative white muscle is elevated during exercise. Changes in the number of feed arteries perforating the muscle are thought to contribute to this altered hyperemic response during exercise. We tested the hypothesis that exercise training would ameliorate age-related differences in blood flow during exercise and feed artery structure in skeletal muscle. Young (6-7 mo old, n = 36) and old (24 mo old, n = 25) male Fischer 344 rats were divided into young sedentary (Sed), old Sed, young exercise-trained (ET), and old ET groups, where training consisted of 10-12 wk of treadmill exercise. In Sed and ET rats, blood flow to the red and white portions of the gastrocnemius muscle (Gast(Red) and Gast(White)) and the number and luminal cross-sectional area (CSA) of all feed arteries perforating the muscle were measured at rest and during exercise. In the old ET group, blood flow was greater to Gast(Red) (264 ± 13 and 195 ± 9 ml · min(-1) · 100 g(-1) in old ET and old Sed, respectively) and lower to Gast(White) (78 ± 5 and 120 ± 6 ml · min(-1) · 100 g(-1) in old ET and old Sed, respectively) than in the old Sed group. There was no difference in the number of feed arteries between the old ET and old Sed group, although the CSA of feed arteries from old ET rats was larger. In young ET rats, there was an increase in the number of feed arteries perforating the muscle. Exercise training mitigated old age-associated differences in blood flow during exercise within gastrocnemius muscle. However, training-induced adaptations in resistance artery morphology differed between young (increase in feed artery number) and old (increase in artery CSA) animals. The altered blood flow pattern induced by exercise training with old age would improve the local matching of O(2) delivery to consumption within the skeletal muscle.
随着年龄的增长，在运动过程中，流向高氧化红色骨骼肌的血流减少，流向低氧化白色肌肉的血流增加。人们认为，肌肉中穿支动脉数量的变化可能导致运动过程中这种充血反应的改变。我们检验了以下假设：运动训练将改善与年龄相关的运动过程中血流和骨骼肌穿支动脉结构的差异。将年轻（6-7 个月大，n=36）和年老（24 个月大，n=25）雄性 Fischer 344 大鼠分为年轻安静（Sed）、年老安静（Sed）、年轻运动训练（ET）和年老运动训练（ET）组，训练包括 10-12 周的跑步机运动。在 Sed 和 ET 大鼠中，测量了腓肠肌（Gast(Red)和 Gast(White)）红色和白色部分以及穿入肌肉的所有穿支动脉的数量和管腔横截面积（CSA）在休息和运动时。在老年 ET 组中，Gast(Red)的血流增加（老年 ET 和老年 Sed 分别为 264±13 和 195±9ml·min(-1)·100g(-1)），Gast(White)的血流减少（老年 ET 和老年 Sed 分别为 78±5 和 120±6ml·min(-1)·100g(-1)）低于老年 Sed 组。老年 ET 组和老年 Sed 组之间穿支动脉的数量没有差异，尽管老年 ET 大鼠的穿支动脉 CSA 较大。在年轻 ET 大鼠中，穿入肌肉的穿支动脉数量增加。运动训练减轻了腓肠肌运动过程中与年龄相关的血流差异。然而，年轻（穿支动脉数量增加）和年老（动脉 CSA 增加）动物的阻力动脉形态适应训练不同。随着年龄的增长，运动训练引起的血流模式改变将改善骨骼肌内的局部 O2 输送与消耗的匹配。
