Pehme Ando, Alev Karin, Kaasik Priit, Seene Teet
Dept. of Functional Morphology, University of Tartu, Estonia.
J Aging Phys Act. 2004 Jan;12(1):29-44. doi: 10.1123/japa.12.1.29.
The purpose of this study was to investigate the effect of compensatory hypertrophy (CH), heavy-resistance exercise training (HRET), and simultaneous CH and HRET on fast-twitch skeletal-muscle myofibrillar-protein synthesis, myosin heavy-chain (MHC) turnover rate, and MHC-isoform composition in young and old rats. In young animals all treatments intensified myofibrillar-protein synthesis, whereas in old animals with CH protein synthesis remained unchanged. The relative content of MHC I and IID in plantaris muscle increases with age, and the relative content of MHC IIB decreases. HRET and simultaneous CH and HRET decreased the proportion of MHC IIB and IIA and increased that of MHC IID in young rat muscle. In old rat muscle, relative content of MHC IID decreased and that of MHC IIB increased. CH decreased relative content of MHC IIB in both age groups and of MHC IIA in old animals. Relative content of MHC IID increased in both groups, and of MHC IIA, in young animals. MHC in plantaris of young rats turned over much faster in all types of mechanical loading but in old rats only during HRET and its combination with CH.
本研究旨在探讨代偿性肥大（CH）、大负荷抗阻运动训练（HRET）以及CH与HRET联合作用对年轻和老年大鼠快肌骨骼肌肌原纤维蛋白合成、肌球蛋白重链（MHC）转换率以及MHC异构体组成的影响。在年轻动物中，所有处理均增强了肌原纤维蛋白合成，而在进行CH的老年动物中，蛋白合成保持不变。比目鱼肌中MHC I和IID的相对含量随年龄增长而增加，MHC IIB的相对含量则降低。HRET以及CH与HRET联合作用降低了年轻大鼠肌肉中MHC IIB和IIA的比例，增加了MHC IID的比例。在老年大鼠肌肉中，MHC IID的相对含量降低，MHC IIB的相对含量增加。CH降低了两个年龄组中MHC IIB的相对含量以及老年动物中MHC IIA的相对含量。两个组中MHC IID的相对含量均增加，年轻动物中MHC IIA的相对含量也增加。在所有类型的机械负荷下，年轻大鼠比目鱼肌中的MHC转换速度都快得多，但老年大鼠仅在进行HRET及其与CH联合作用时MHC转换速度加快。
