科学家开发了一种有希望的新方法，以打击肌肉质量中与年龄相关的损失，这种损失通常伴随着受伤或疾病后的固定性。他们的技术在小鼠中证明，逮捕了一段不活动后运动开始时肌肉开始恶化的过程。

他们在Journal of Physiology.

Exercise, particularly engagement in load-bearing activities, helps retain muscle mass – and is particularly important as one ages, saidMarni Boppart，教授运动学和社区健康领导研究的伊利诺伊大学Urbana-Champaign大学。伤害或疾病会导致肌肉质量的固定时期和下降。

博帕特说：“当我们无法收缩肌肉时，它会萎缩。”“如果这种固定性持续很长时间，那么肌肉质量和力量将大大损失。”

博帕特说，儿童和年轻人的肌肉在恢复运动后倾向于迅速康复。“但不幸的是，对于老年人来说，他们在废弃一段时间后无法恢复肌肉质量的能力。”

Physical therapy is often prescribed to promote healing after injury and immobility, she said. But studies show that muscle continues to deteriorate after the onset of exercise. Reactive oxygen species, a signal of inflammation and cellular dysfunction, accumulate in the muscles and impede the healing process.

Boppart’s research focuses on the factors that enhance or degrade muscle mass in aging. In a先前的研究, she and her colleagues discovered that injections of support cells known as pericytes contributed to muscle recovery in young mice after a period of immobility. However, aged mice did not respond as well to the injections, and recovery was limited.

In the new study, the team collected pericytes from the muscles of young, healthy mice and grew them in cell culture. They exposed the cells to hydrogen peroxide – a powerful oxidant that promotes the production of extracellular vesicles containing factors that combat stress and enhance healing – and collected the EVs to use therapeutically.

Boppart说，细胞外囊泡对于细胞间的交流至关重要，可以用作健康和疾病的生物标记。先前的研究表明，它们也是压力和愈合的强大生物学介质。

“For example, you can take the blood of young mice, collect the EVs from the blood and inject them into aged mice, and they now have a younger collection of traits, known as a phenotype,” she said. “You can take healthy EVs from mouse blood, introduce them into a diabetic mouse and it reverses diabetes.”

No studies have explored the use of EVs to support muscle recovery, however, Boppart said.

研究人员将其周围的衍生电动汽车注入了年轻小鼠和老年小鼠的肌肉中，这些小鼠在其中一条腿上长时间肌肉不动，并开始再次使用这些肌肉。

该方法有效：用刺激的电动汽车恢复的骨骼肌纤维大小和老年小鼠的骨骼肌大小处理的小鼠。该研究还首次揭示了从肌肉周细胞衍生的电动汽车产生了各种因素，这些因素可能会打击炎症和氧化应激。

Using EVs has many advantages over whole-cell therapies, Boppart said. Cells cannot be collected, frozen and stored until needed for transplantation, but EVs can. Early studies suggest that animals do not mount an immune response to injected EVs, but more research is needed to test those findings.

但是，研究人员发现年轻和老年小鼠对受刺激的电动汽车的反应有所不同。年轻小鼠未检测到的年轻小鼠的活性氧可测量的减少。尽管有这种差异，但年轻小鼠和老年小鼠都重塑了细胞外基质，该基质支持肌肉结构和生长，并且与未经治疗的小鼠相比，肌肉纤维尺寸恢复了。

博帕特说：“在这项研究之前，我们不知道周细胞是如何工作的。”“我们只是知道他们正在分泌可能有助于恢复过程的有益因素。现在，我们可以更好地了解他们这样做的机制。我们知道如何刺激他们做得更好。”

参考: Wu YF, Toba EADL, Dvoretskiy S, et al. Development of a cell-free strategy to recover aged skeletal muscle after disuse.生理学杂志。2022. doi:10.1113/jp282867

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