Exercise Physiology Research Group, Department of Movement Sciences, KU Leuven, Tervuursevest 101, 3001, Leuven, Belgium.
Sci Rep. 2021 Sep 15;11(1):18349. doi: 10.1038/s41598-021-97859-3.
Aged skeletal muscle undergoes metabolic and structural alterations eventually resulting in a loss of muscle strength and mass, i.e. age-related sarcopenia. Therefore, novel targets for muscle growth purposes in elderly are needed. Here, we explored the role of the cannabinoid system in muscle plasticity through the expression of muscle cannabinoid receptors (CBs) in young and old humans. The CB expression was higher (+ 25%; p = 0.04) in muscle of old (≥ 65 years) vs. young adults (20-27 years), whereas CB was not differently expressed. Furthermore, resistance exercise tended to increase the CB (+ 11%; p = 0.055) and CB (+ 37%; p = 0.066) expression in muscle of older adults. Interestingly, increases in the expression of CB following resistance exercise positively correlated with changes in key mechanisms of muscle homeostasis, such as catabolism (FOXO3a) and regenerative capacity (Pax7, MyoD). This study for the first time shows that CB is differentially expressed with aging and that changes in CB expression upon resistance exercise training correlate with changes in mediators that play a central role in muscle plasticity. These data confirm earlier work in cells and mice showing that the cannabinoid system might orchestrate muscle growth, which is an incentive to further explore CB-based strategies that might counteract sarcopenia.
衰老的骨骼肌会发生代谢和结构改变，最终导致肌肉力量和质量的丧失，即与年龄相关的肌肉减少症。因此，需要寻找新的靶点来促进老年人的肌肉生长。在这里，我们通过检测年轻人和老年人肌肉中肌肉大麻素受体（CB）的表达，研究了大麻素系统在肌肉可塑性中的作用。结果显示，与年轻人（20-27 岁）相比，老年人（≥65 岁）肌肉中的 CB 表达更高（增加 25%；p=0.04），而 CB 则没有差异表达。此外，抗阻运动似乎会增加老年人肌肉中的 CB（增加 11%；p=0.055）和 CB（增加 37%；p=0.066）的表达。有趣的是，抗阻运动后 CB 表达的增加与肌肉内关键的稳态机制变化呈正相关，如分解代谢（FOXO3a）和再生能力（Pax7、MyoD）。本研究首次表明，CB 在衰老过程中存在差异表达，抗阻运动训练后 CB 表达的变化与在肌肉可塑性中起核心作用的介质的变化相关。这些数据证实了早期在细胞和小鼠中的研究工作，表明大麻素系统可能协调肌肉生长，这激励我们进一步探索基于 CB 的策略，以对抗肌肉减少症。
