Buford Thomas W, MacNeil R Gavin, Clough Launa G, Dirain Marvin, Sandesara Bhanuprasad, Pahor Marco, Manini Todd M, Leeuwenburgh Christiaan
Department of Aging and Geriatric Research, College of Medicine, University of Florida, Gainesville, Florida; and Department of Applied Physiology and Kinesiology, College of Health & Human Performance, University of Florida, Gainesville, Florida
Department of Aging and Geriatric Research, College of Medicine, University of Florida, Gainesville, Florida; and Department of Applied Physiology and Kinesiology, College of Health & Human Performance, University of Florida, Gainesville, Florida.
J Appl Physiol (1985). 2014 Jun 1;116(11):1481-90. doi: 10.1152/japplphysiol.01350.2012. Epub 2013 Mar 14.
Repair of skeletal muscle after injury is a key aspect of maintaining proper musculoskeletal function. Studies have suggested that regenerative processes, including myogenesis and angiogenesis, are impaired during advanced age, but evidence from humans is limited. This study aimed to compare active muscle regeneration between healthy young and older adults. We evaluated changes in clinical, biochemical, and immunohistochemical indices of muscle regeneration at precisely 2 (T2) and 7 (T3) days following acute muscle injury. Men and women, aged 18-30 and ≥70 years, matched for gender and body mass index, performed 150 unilateral, eccentric contractions of the plantar flexors at 110% of one repetition maximum. Data were analyzed using analysis of covariance, adjusted for gender, habitual physical activity, and baseline level of the outcome. A total of 30 young (n = 15; 22.5 ± 3.7 yr) and older (n = 15; 75.8 ± 5.0 yr) adults completed the study. Following muscle injury, force production declined 16% and 14% in young and older adults, respectively, by T2 and in each group, returned to 93% of baseline strength by T3. Despite modest differences in the pattern of response, postinjury changes in intramuscular concentrations of myogenic growth factors and number of myonuclear (4',6-diamidino-2-phenylindole+ and paired box 7+) cells were largely similar between groups. Likewise, postinjury changes in serum and intramuscular indices of inflammation (e.g., TNF-α and monocyte chemoattractant protein-1) and angiogenesis (e.g., VEGF and kinase insert domain receptor) did not differ significantly between groups. These findings suggest that declines in physical activity and increased co-morbidity may contribute to age-related impairments in active muscle regeneration rather than aging per se.
损伤后骨骼肌的修复是维持正常肌肉骨骼功能的关键方面。研究表明，包括肌生成和血管生成在内的再生过程在老年时会受损，但来自人类的证据有限。本研究旨在比较健康年轻人和老年人之间活跃的肌肉再生情况。我们评估了急性肌肉损伤后第2天（T2）和第7天（T3）时肌肉再生的临床、生化和免疫组化指标的变化。年龄在18 - 30岁和≥70岁的男性和女性，按性别和体重指数匹配，以一次重复最大值的110%进行150次单侧跖屈肌的离心收缩。使用协方差分析对数据进行分析，并对性别、习惯性身体活动和结果的基线水平进行了调整。共有30名年轻人（n = 15；22.5 ± 3.7岁）和老年人（n = 15；75.8 ± 5.0岁）完成了研究。肌肉损伤后，到T2时，年轻人和老年人的力量产生分别下降了16%和14%，并且在每组中，到T3时恢复到基线力量的93%。尽管反应模式存在适度差异，但两组之间损伤后肌源性生长因子的肌肉内浓度变化和肌核（4',6 - 二脒基 - 2 - 苯基吲哚 + 和配对盒7 +）细胞数量变化在很大程度上相似。同样，两组之间损伤后血清和肌肉内炎症指标（如TNF - α和单核细胞趋化蛋白 - 1）以及血管生成指标（如VEGF和激酶插入结构域受体）的变化没有显著差异。这些发现表明，身体活动的下降和合并症的增加可能导致与年龄相关的活跃肌肉再生受损，而不是衰老本身。
