纤维大小与肌核域的问题：大小比年龄更重要吗？
Matters of fiber size and myonuclear domain: Does size matter more than age?
作者信息
Karlsen Anders, Couppé Christian, Andersen Jesper L, Mikkelsen Ulla R, Nielsen Rie H, Magnusson S Peter, Kjaer Michael, Mackey Abigail L
机构信息
Institute of Sports Medicine, Department of Orthopaedic Surgery M, Bispebjerg Hospital, Building 8, Bispebjerg Bakke 23, 2400, Copenhagen, NV, Denmark.
Department of Biomedical Sciences, Centre for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
出版信息
Muscle Nerve. 2015 Dec;52(6):1040-6. doi: 10.1002/mus.24669. Epub 2015 Sep 28.
INTRODUCTION
The relationship between fiber size and myonuclear content is poorly understood.
METHODS
Biopsy cross-sections from young and old trained and untrained healthy individuals were analyzed for fiber area and myonuclei, and 2 fiber-size-dependent cluster analyses were performed.
RESULTS
When comparing fibers of similar size, no effect of training or age was found for myonuclear domain. There was a linear relationship between fiber area and myonuclei per fiber (r = 0.99; P < 0.001) and a non-linear relationship between fiber area and domain (r = 0.97-0.99; P < 0.0001), with a markedly smaller domain in fibers <3,000 µm(2). A higher proportion of type II fibers <3,000 µm(2) was observed in the old subjects.
CONCLUSIONS
These findings suggest that age-related reductions in myonuclear domain size could be explained by the greater proportion of small fibers. The data also highlight the usefulness of determining fiber-size-based clusters for gaining mechanistic insight into the relationship between skeletal muscle fiber size and myonuclear content.
引言
纤维大小与肌核含量之间的关系尚不清楚。
方法
对年轻和年老的受过训练和未受过训练的健康个体的活检横截面进行纤维面积和肌核分析，并进行了2次基于纤维大小的聚类分析。
结果
在比较大小相似的纤维时，未发现训练或年龄对肌核域有影响。纤维面积与每根纤维的肌核之间存在线性关系（r = 0.99；P < 0.001），纤维面积与域之间存在非线性关系（r = 0.97 - 0.99；P < 0.0001），在<3,000 µm²的纤维中域明显更小。在老年受试者中观察到<3,000 µm²的II型纤维比例更高。
结论
这些发现表明，与年龄相关的肌核域大小的减少可以用小纤维比例更高来解释。数据还突出了确定基于纤维大小的聚类对于深入了解骨骼肌纤维大小与肌核含量之间关系的作用。
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