Muscular hypertrophy and changes in cytokine production after eccentric training in the rat skeletal muscle

Eisuke Ochi, Koichi Nakazato, Naokata Ishii

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Ochi, E, Nakazato, K, and Ishii, N. Muscular hypertrophy and changes in cytokine production after eccentric training in the rat skeletal muscle. J Strength Cond Res 25(8): 2283-2292, 2011-We investigated the time course effects of eccentric training on muscular size, strength, and growth factor/cytokine production by using an isokinetic-exercise system for rats. Male Wistar rats (n = 34) were randomly assigned into 4 groups: 5 session eccentric-training group (ECC5S, n = 10); 5 session sham-operated group (CON5S, n = 10); 10 session eccentric-training group (ECC10S, n = 7); 10 session sham-operated group (CON10S, n = 7). In each group, a session of either training or sham operation was performed every 2 days. The training consisted of 4 sets of forced dorsiflexion (5 repetitions) combined with electric stimulation of plantar flexors. The wet weight of medial gastrocnemius muscle did not increase significantly after 5 sessions of training, whereas that after 10 sessions of training significantly increased with a concomitant increase in the cross-sectional area (CSA) of muscle fibers (weight, p < 0.05; fiber CSA, p < 0.001). Interleukin (IL)-6 in ECC5S and ECC10S groups showed significant increases (p < 0.01), whereas those of tumor necrosis factor (TNF)-α and IL-10 did not. The phospho-stat-3 showed a significant increase in ECC10S (p < 0.001) but not in ECC5S. Myostatin and follistatin also showed significant differences only between ECC10S and CON10S (p < 0.05). The results showed that repeated sessions of eccentric training for 20 days cause increases in muscular size and strength associated with increases in IL-6, follistatin, phospho-stat-3, and a decrease in myostatin. The delayed responses of IL-6, myostatin, phospho-stat-3, and follistatin would be due to the chronic effects of repeated training and possibly important for muscular hypertrophy.

Original languageEnglish
Pages (from-to)2283-2292
Number of pages10
JournalJournal of Strength and Conditioning Research
Volume25
Issue number8
DOIs
Publication statusPublished - Aug 1 2011

Keywords

  • Cytokine
  • Eccentric contraction
  • Exercise
  • Growth factor
  • Muscle strength

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

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