Effects of aging on shortening velocity and myosin isoform composition in single human skeletal muscle cells
Effects of aging on shortening velocity and myosin isoform composition in single human skeletal muscle cells
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DOI：
10.1152/ajpcell.1997.272.2.c638
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发表时间：
1997-02-01
影响因子：
5.5
通讯作者：
Frontera, WR
中科院分区：
文献类型：
--
作者：
Larsson, L;Li, XP;Frontera, WR
测定了400个年轻（n = 4，25-31岁）和老年（n = 4，78-81岁）男性单股四头肌细胞的最大无负荷缩短速度（V-O）和最大力（标准化为横截纤维面积（比张力））。其中两名老年人身体非常活跃，受试者被分为年轻对照组，老年对照组和老年身体活动组。通过6和12%十二烷基硫酸钠-聚丙烯酰胺凝胶电泳测定I型、IIa型和IIb型肌球蛋白重链（MHC）以及必需和调节肌球蛋白轻链的表达。V-O是高度依赖于MHC亚型的组成，并观察到一个梯度，从吹到快的序列I：I-IIa，IIa，IIab，和IIb，MHC细胞。青年对照组Ⅰ、Ⅱ a型MHC纤维的V-O值和比张力均显著高于老年对照组和老年运动组。因此，本研究结果提供了证据的质量变化的人骨骼肌的收缩性能在老年，这可能发挥重要作用，与年龄相关的骨骼肌功能障碍。
Maximum unloaded shortening velocity (V-O) and maximum force normalized to cross-sectional fiber area (specific tension) were determined in 400 single quadriceps muscle cells of young (n = 4, 25-31 yr) and old (n = 4, 78-81 yr) men. Two of the old men were physically very active, and the subjects were divided into young control, old control, and old physically active groups. The expressions of types I, IIa, and IIb myosin heavy chains (MHC) and essential and regulatory myosin light chains were determined by 6 and 12% sodium dodecyl sulfate-polyacrylamide gel electrophoresis. V-O was highly dependent on the MHC isoform composition, and a gradient from Blow to fast was observed in the sequence I: I-IIa, IIa, IIab, and IIb, MHC cells. The V-O values and specific tensions of types I and IIa MHC fibers in the young control group mere significantly higher than those in the old control and old physically active groups. Thus the present results provide evidence of qualitative changes in contractile properties of human skeletal muscle in old age, which probably play an important role in the age-related impairment of skeletal muscle function.