Whole-Body Vibration Partially Reverses Aging-Induced Increases in Visceral Adiposity and Hepatic Lipid Storage in Mice

At old age, humans generally have declining muscle mass and increased fat deposition, which can increase the risk of developing cardiometabolic diseases. While regular physical activity postpones these age-related derangements, this is not always possible in the elderly because of disabilities or risk of injury. Whole-body vibration (WBV) training may be considered as an alternative to physical activity particularly in the frail population. To explore this possibility, we characterized whole-body and organ-specific metabolic processes in 6-month and 25-month old mice, over a period of 14 weeks of WBV versus sham training. WBV training tended to increase blood glucose turnover rates and stimulated hepatic glycogen utilization during fasting irrespective of age. WBV was effective in reducing white fat mass and hepatic triglyceride content only in old but not in young mice and these reductions were related to upregulation of hepatic mitochondrial uncoupling of metabolism (assessed by high-resolution respirometry) and increased expression of uncoupling protein 2. Because these changes occurred independent of changes in food intake and whole-body metabolic rate (assessed by indirect calorimetry), the liver-specific effects of WBV may be a primary mechanism to improve metabolic health during aging, rather than that it is a consequence of alterations in energy balance.

步入老年后，人体通常会出现肌肉量下降、脂肪沉积增加的情况，这会提升心血管代谢疾病的发病风险。尽管规律的体育锻炼可延缓这些与衰老相关的代谢紊乱，但老年群体常因身体残疾或受伤风险而难以坚持规律运动。全身振动（Whole-body vibration，WBV）训练可作为体育锻炼的替代方案，尤其适用于衰弱人群。为探究这一可行性，本研究对6月龄与25月龄小鼠开展了为期14周的WBV训练与假训练对照实验，表征其全身及器官特异性代谢过程。无论小鼠年龄如何，WBV训练均倾向于提升血糖周转率，并在禁食状态下促进肝脏糖原的利用。仅在老年小鼠中，WBV训练可有效降低白色脂肪组织重量与肝脏甘油三酯含量，而对年轻小鼠无此效果；上述变化与肝脏线粒体代谢解偶联作用（通过高分辨率呼吸测定法评估）的上调以及解偶联蛋白2（uncoupling protein 2）表达的提升密切相关。由于上述变化的发生与食物摄入量及全身代谢率（通过间接测热法评估）的变化无关，因此WBV训练的肝脏特异性效应或许是改善衰老过程中代谢健康的核心机制，而非能量平衡改变所带来的继发结果。