在两周不运动后，单剂量的健康免疫细胞加速了老年小鼠肌肉功能的恢复, according to University of Utah Health scientists. 他们说，这一发现最终可能会导致加速肌肉修复的治疗方法的发展，并大发娱乐老年人从跌倒和其他伤害中恢复得像年轻人一样快.
“Many people may not realize it, 但免疫系统在肌肉修复和恢复中起着至关重要的作用,” says Micah Drummond, Ph.D., 他是uu of U Health的物理治疗和运动训练教授，也是该研究的通讯作者, which appears in the Journal of Applied Physiology.
“然而，随着年龄的增长，免疫细胞对肌肉组织损伤的反应往往会减弱. We believe that, 如果大发娱乐能找到一种方法让老化肌肉中的免疫系统恢复活力, 然后大发娱乐也许能够大发娱乐老年人保持或恢复他们离开椅子的能力, climb stairs, and live better lives.”
Older, weaker muscle contributes to falls, injuries
With age, muscles get smaller and weaker, 使人更容易受到跌倒和其他事故的伤害. In fact, one out of every five falls causes an injury, such as broken bones, and at least 300,000 older adults are hospitalized for hip fractures 根据美国疾病控制与预防中心的数据.
“当大发娱乐把老的免疫细胞给老动物时，大发娱乐认为这可能会让它们变得更糟. But to our surprise, they actually improved.”
“Every year, far too many older people lose their ability to move, stand, and go about their everyday lives,” Drummond says. “大发娱乐希望防止这种情况发生，让他们的肌肉恢复到应有的状态.”
Normally, when an injury such as an ankle sprain occurs, 患处的肌肉会向免疫系统发出信号，吸引白细胞到受损组织. Some of these white blood cells, called macrophages, 引起肿胀，但也能清除损伤部位的碎片，并促使干细胞协调肌肉组织的再生.
However, as we get older, 参与这一过程的免疫细胞不能像大发娱乐年轻时那样有效地刺激肌肉修复, according to Drummond.
Making old muscle act young again
以确定是否可以恢复某些修复活动, 德拉蒙德和他的同事来自牛津大学健康大学和迈阿密大学, Ohio, conducted a series of experiments in laboratory mice.
In their first experiment, 研究人员通过限制幼鼠和老年实验鼠后腿活动14天来削弱它们的肌肉. 然后给这些小鼠注射一剂巨噬细胞，这些巨噬细胞取自一组年轻和年老的小鼠，这些小鼠被允许自由活动. 另一组运动受限的小鼠给予生理盐水治疗作为对照.
研究人员发现，与对照组相比，接受其他年轻小鼠免疫细胞的实验年轻小鼠在肌肉恢复方面没有差异. However, the older experimental mice, when given immune cells from younger mice, 肌肉力量恢复到与保持体力活动的老年小鼠几乎相同的水平吗.
In contrast, 当年轻的实验小鼠接受老年小鼠的免疫细胞时, their muscles became weaker, 这表明老的免疫细胞有些功能失调, Drummond says.
Interestingly, when older mice were given old donor immune cells, 他们的肌肉力量在恢复过程中显著提高, he says.
“当大发娱乐把老的免疫细胞给老动物时，大发娱乐认为这可能会让它们变得更糟,” Drummond says. “But to our surprise, they actually improved.”
德拉蒙德的理论是，即使年老的免疫细胞比年轻的免疫细胞效率低一点, they still have the potential to make a difference, 特别是当足够的它们被引入肌肉时.
“They may not be 100% effective, but if you get a bunch of them together in a muscle, they probably can still do their job,” Drummond says. “而在较年轻的动物中，不需要那么多，因为它们的免疫细胞处于最佳状态，非常有效.”
更好的细胞交流也会加速肌肉的恢复
研究人员指出，免疫细胞功能障碍只是导致老年肌肉恢复不良的几个因素之一. In some cases, 有可能是肌肉细胞没有向免疫系统发出足够的正确信号, Drummond says. 因此，能够大发娱乐恢复肌肉的巨噬细胞减少了.
To test this notion, 研究人员给一些年老的实验小鼠注射了一种叫做巨噬细胞集落刺激因子（MCSF）的生长因子，这种生长因子通常会提醒免疫系统开始修复受损的肌肉. Overall, 与对照组相比，给予MCSF的老年小鼠产生了更多的巨噬细胞免疫细胞，肌肉力量也更大.
Although this research shows promises, 德拉蒙德强调，在将其用于人类之前，还需要做更多的工作.
“大发娱乐正在寻找许多可能使免疫细胞恢复活力并使其更有效地恢复肌肉功能的因素,” he says. “But we still have more experiments to do.”
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除了Micah Drummond，犹他大学健康研究人员E.M Yee, J.J. Petrocelli, D.K. Fix, C.T. Hauser, N.M.M.P. de Hart, Z.S. Mahmassani, and R.M. O’Connell contributed to this study. P. T. 俄亥俄州牛津市迈阿密大学的雷迪也参与了这项研究.
The study, 巨噬细胞免疫调节加速老年小鼠废用性萎缩后骨骼肌功能恢复,” appears in the Journal of Applied Physiology. 这项研究得到了国家衰老研究所（NIA）和国家关节炎、肌肉骨骼和皮肤疾病研究所（NIAMS）的支持。.