Reduction of Preserved Capacity for Skeletal Muscle with Aging and Effect of Exercise

程序- 1a自动转轮，其中已知负载可以电子添加。自愿运动加上额外的负荷会导致纤维肥大，这与平均跑步距离成正比。此外，在负荷跑步运动中，所有运动单元类型的招募都被诱导，因为在肌肉的所有纤维类型中都观察到纤维肥大。程序2用10周龄、60周龄和120周龄大鼠研究了胫骨前肌和比目鱼肌肌肉纤维和运动神经元数量和SDH活性的年龄相关性变化。60周龄时快肌纤维数量减少，120周龄时慢肌纤维和α运动神经元数量减少。大α运动神经元SDH活性在120周龄时明显降低。因此，肌纤维的退行性过程在快肌和慢肌之间是不同的。方案340周龄大鼠自愿在负重增加的跑轮上运动20周。与20周龄相比，60周龄比目鱼肌中的FOG纤维和胫前肌中的FG纤维较少。60周龄大鼠胫骨前肌中FOG和FG纤维的截面积低于20周龄大鼠。运动可防止胫前肌纤维的萎缩。这些发现表明，运动可以通过恢复其下降的代谢能力和抑制神经肌肉连接处的退化来预防FOG纤维的萎缩。

Program-1A voluntary running wheel in which a known load can be added electronically was developed. A voluntary exercise with an additional load resulted in fiber hypertrophy which was proportional to the average running distance. In addition, a recruitment of all motor unit type was induced during loaded-running exercise since fiber hypertrophy was observed in all fiber types in the muscle.Program-2The age-related changes in the number and SDH activity of muscle fibers and motoneurons of the tibialis anterior and soleus were studied using 1 0-, 60-, and 120-week-old rats. The number of fast-twitch muscle fibers was decreased at 60 weeks of age, while the number of slow-twitch muscle fibers and alpha motoneurons was decreased at 1 20 weeks of age. In addition, SDH activity of large alpha motoneurons was decreased at 1 20 weeks of age. Therefore, the degenerative process of muscle fibers differs between the fast- and slow-twitch muscles.Program-3Forty-week-old rats exercised voluntarily in running wheels with increasing loads for 20 weeks. There were fewer FOG fibers in the soleus muscle, and fewer FG fibers in the tibialis anterior muscle at 60 weeks than at 20 weeks of age. The cross-sectional area of FOG and FG fibers in the tibialis anterior muscle was lower at 60 weeks than at 20 weeks of age. Exercise prevented atrophy of FOG fibers in the tibialis anterior muscle. These findings suggest that exercise can prevent the atrophy of FOG fibers by restoring their decreased metabolic capacity, and by inhibiting the degeneration of neuromuscular junctions.