Age and sex differences in satellite cell activation during step up and down exercise

2019 Fiscal Year Final Research Report

• Project/Area Number: 16H03221
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Developmental mechanisms and the body works
• Research Institution: Yamaguchi University
• Principal Investigator: MIYATA Hirofumi 山口大学, 大学院創成科学研究科, 教授 (90190793)
• Co-Investigator(Kenkyū-buntansha): 山本 直樹 山口大学, 大学教育機構, 准教授 (90448283)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Keywords: 踏み台昇降運動 / エキセントリック収縮 / サテライトセル / 性差 / 年齢差

Outline of Final Research Achievements

By step exercise using the height of 80%, 90%, and 100% of each subject's lower leg length, the increase in heart rate was higher in female than male regardless of age. In the left leg (supporting leg) during the exercise, significantly higher muscle soreness occurred at 2 days after exercise in all groups, and higher values were observed in female than male groups. These results reflected the sexual difference in muscle mass per body weight. In addition, a large eccentric contraction were occurred in the left thigh (support leg) during the exercise, and no differences were observed among all groups.
Furthermore, significant activation of satellite cells occurred at the same time as an increase in muscle pain marker molecules in rat lower leg muscles that are forcibly loaded with eccentric contraction. Moreover, it was clarified that satellite cell activation occurs in the lower leg muscle exposed to intermittent hypoxic environment in young mice, but not at old mice.

Free Research Field

運動生理学

Academic Significance and Societal Importance of the Research Achievements

筋力トレーニングに対する骨格筋線維の適応変化は，年齢および性別による差異が報告されており，その背景には筋原性前駆細胞であるサテライトセルの応答の違いがあると考えられている。
性別および年齢を考慮しながら踏み台の高さおよび歩行様式を変えることで，抗重力筋に対して安全にかつ効果的な筋収縮を発生させることが可能である。そして，その運動中に発生するエキセントリック収縮は，筋サテライトセルの活性化を誘発し，効果的な筋力トレーニングとなる可能性がある。