Interleukin-6 maintains glucose homeostasis to support strenuous masseter muscle activity in mice

Masahiro Tsuchiya, Tomomi Kiyama, Shinobu Tsuchiya, Hirohisa Takano, Eiji Nemoto, Keiichi Sasaki, Makoto Watanabe, Shunji Sugawara, Yasuo Endo

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

The cytokine interleukin-6 (IL-6) is released from working skeletal muscles and reportedly plays key roles in their glucose homeostasis. However, it is unclear whether IL-6 plays such roles in the masseter muscle (MM), which is important in normal and pathological chewing behaviors, such as bruxism and/or prolonged clenching. When restrained (R+) in a narrow cylinder blocked at the front end with a thin plastic strip, a mouse gnaws away (G+) the strip to escape. The absolute weight of plastic gnawed away serves as an index of MM activity. Using this model, we examined the roles of IL-6 in MM with the following results. R+G+ increased the expression levels of IL-6 and glucose transporter 4 (Glut4) mRNAs in MM and the serum level of IL-6 protein. IL-6-defcient mice exhibited about 60% less gnawing activity than wild-type mice at 3-4 h after the start of R+G+, slower recovery of glycogen levels (indicating poorer glucose supply) in MM after R+G+, and no signifcant change in Glut4 mRNA in MM upon R+G+. During an R+G+ test conducted after "training" (repeated R+G+ sessions), wild-type mice exhibited greater gnawing activity than untrained controls, but no increase in IL-6 mRNA in MM. IL-6 mRNA increased in MM when hard food was eaten by mice raised on soft food for 3 weeks from weaning, but not in those raised on (accustomed to) hard food. Thus, IL-6 may maintain glucose homeostasis in MM in support of unusually strenuous activity, but not of accustomed activity levels.

Original languageEnglish
Pages (from-to)109-117
Number of pages9
JournalTohoku Journal of Experimental Medicine
Volume227
Issue number2
DOIs
Publication statusPublished - 2012

Keywords

  • Fatigue
  • Glucose homeostasis
  • Interleukin-6
  • Masseter muscle
  • Mastication

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

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