1Exercise Physiology Laboratory, Department of Kinesiology, University of North Carolina at Charlotte, Charlotte, NC;2Biodynamics Research Laboratory, Department of Kinesiology, University of North Carolina at Charlotte, Charlotte, NC; and 3Center for Biomedical Engineering and Science, University of North Carolina at Charlotte, Charlotte, NC.
Med Sci Sports Exerc. 2013 Oct;45(10):1933-40. doi: 10.1249/MSS.0b013e318293b019.
The purpose of this study was to investigate the age-related changes in diastolic filling parameters in the aging hearts of active C57Bl/6J mice throughout the life span to indicate optimal age periods for improvements in resting diastolic parameters.
Fourteen C57Bl/6J mice (seven males and seven females) were individually housed at 8 wk of age in cages with a running wheel, magnetic sensor, and digital odometer. Duration, distance, and running velocity were recorded daily. Fourteen additional mice C57Bl/6J mice (seven males and seven females) were placed in individual cages without running wheels at 8 wk of age. Pulsed-wave Doppler transmitral inflow recordings with a SONOS 5500 ultrasound and 15-6L ultrasound probe were used to image the left ventricle every 4 wk throughout the life span.
Peak E wave filling velocities were significantly greater by the start of the second quarter of the life span in the mice with access to running wheels (P < 0.0001). Peak E wave velocities improved in both groups during the first half of the life span (P < 0.0001) and declined throughout the second half of the life span (P < 0.0001). Early-to-late (E:A) filling ratio was significantly greater for the physically active mice by the start of the second quarter of the life span (P < 0.0001) and continued throughout most of the remainder of the life span (P < 0.0001). No differences were observed between the two groups of mice with peak A wave filling velocities (P > 0.05). Similar findings were observed when corrected for resting heart rate.
Lifelong physical activity resulted in greater diastolic filling parameters by the second quarter of the life span, highlighting the clinical importance of regular aerobic activity in young adulthood as a mechanism for improved left ventricular performance with aging.
本研究旨在探讨活跃的 C57Bl/6J 小鼠衰老心脏舒张充盈参数随年龄的变化，以确定改善静息舒张参数的最佳年龄阶段。
14 只 C57Bl/6J 小鼠（7 只雄性，7 只雌性）于 8 周龄时单独饲养在带有跑步轮、磁传感器和数字里程表的笼子中。每天记录持续时间、距离和跑步速度。另外 14 只 C57Bl/6J 小鼠（7 只雄性，7 只雌性）于 8 周龄时被放置在没有跑步轮的单独笼子中。使用 SONOS 5500 超声仪和 15-6L 超声探头进行脉冲波多普勒二尖瓣前向血流记录，在整个生命周期中每 4 周对左心室进行成像。
有跑步轮的小鼠在生命第二季度开始时，峰值 E 波充盈速度显著增加（P < 0.0001）。两组在生命前半段的峰值 E 波速度都有所提高（P < 0.0001），并在生命后半段下降（P < 0.0001）。在生命第二季度开始时，活跃组的早期到晚期（E:A）充盈比显著增加（P < 0.0001），并在大部分剩余生命期间持续增加（P < 0.0001）。两组的峰值 A 波充盈速度没有差异（P > 0.05）。当校正静息心率时，也观察到了相似的发现。
终生的体力活动导致舒张充盈参数在生命的第二季度增加，突出了在年轻成年期进行有规律的有氧运动的临床重要性，这是改善衰老时左心室功能的机制。
