The molecular response of skeletal muscle injury after repeated bouts of eccentric contractions

2014 Fiscal Year Final Research Report

• Project/Area Number: 23700784
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Sports science
• Research Institution: Okayama University (2014); Meiji Gakuin University (2011-2013)
• Principal Investigator: OCHI EISUKE 岡山大学, 教育学研究科(研究院), 講師 (90468778)
• Co-Investigator(Renkei-kenkyūsha): NAKAZATO Koichi 日本体育大学, 大学院体育科学研究科, 教授 (00307993) ; ISHII Naokata 東京大学, 大学院総合文化研究科, 教授 (20151326)
• Project Period (FY): 2011-04-28 – 2015-03-31
• Keywords: 筋損傷 / 肉ばなれ / 伸張性収縮 / 萎縮 / タンパク質 / アポトーシス / 瘢痕化 / 線維化

Outline of Final Research Achievements

One bout of exercise consisting of fast velocity eccentric contractions has been shown to increase muscle protein degradation in rats. The present study tested the hypothesis that repeated bouts of fast velocity eccentric contractions would activate molecules inducing muscle atrophy. Gastrocnemius wet mass were smaller, cross-sectional area of medial gastrocnemius was smaller, and isometric tetanic torque of triceps surae muscles was 36% smaller for 180EC than control at 1 day after the fourth session, but no such differences were evident between 30EC and control. However, no muscle fibers infiltrated by inflammatory cells or with centrally-located nuclei were observed for any rats. The expressions of atrophy-related molecules such as FoxO1, FoxO3 and myostatin were unregulated only for 180EC, but an increase in phosphorylated p70s6k was found only for 30EC at 1 day after the fourth session. The level of Bax, a pro-apoptotic protein, was greater for 180EC than control.

Free Research Field

スポーツ科学