Microbiota protect against frailty, loss of skeletal muscle, and maintain inflammatory tone during aging in mice

We showed that germ-free mice had increased frailty, lower muscle mass, and lower circulating inflammatory monocytes. Therefore, lower systemic inflammation coincided with worse frailty and muscle loss. Microbial colonization decreased frailty, restored muscle mass, and increased circulating inflammatory monocytes while lowering transcripts in inflammatory TNF and NF-kB pathways within muscle. Hence, microbiota can increase circulating inflammation but decrease muscle inflammation to protect against frailty.

本研究证实，无菌小鼠（germ-free mice）存在更高程度的虚弱、更低的肌肉量，以及更低的循环炎性单核细胞水平。由此可见，全身炎症水平较低与更严重的虚弱及肌肉丢失相伴发生。微生物定植可减轻小鼠的虚弱程度、恢复肌肉量，并提升循环炎性单核细胞水平，同时下调肌肉内炎性TNF（Tumor Necrosis Factor，肿瘤坏死因子）与NF-κB（Nuclear Factor-kappa B，核因子κB）通路的转录本表达。综上，微生物群可升高循环炎症水平，但降低肌肉局部炎症，从而发挥抵御虚弱的作用。