Interleukin-6 mediates exercise preconditioning against myocardial ischemia reperfusion injury

Graham Ripley McGinnis, Christopher Ballmann, Bridget Peters, Gayani Nanayakkara, Michael Roberts, Rajesh Amin, John C. Quindry

Research output: Contribution to journalArticlepeer-review

78 Scopus citations

Abstract

Interleukin-6 (IL-6) is a pleiotropic cytokine that protects against cardiac ischemia-reperfusion (I/R) injury following pharmacological and ischemic preconditioning (IPC), but the affiliated role in exercise preconditioning is unknown. Our study purpose was to characterize exercise-induced IL-6 cardiac signaling (aim 1) and evaluate myocardial preconditioning (aim 2). In aim 1, C57 and IL-6-/- mice underwent 3 days of treadmill exercise for 60 min/day at 18 m/min. Serum, gastrocnemius, and heart were collected preexercise, immediately postxercise, and 30 and 60 min following the final exercise session and analyzed for indexes of IL-6 signaling. For aim 2, a separate cohort of exercise-preconditioned (C57 EX and IL-6-/- EX) and sedentary (C57 SED and IL-6-/- SED) mice received surgical I/R injury (30 min I, 120 min R) or a time-matched sham operation. Ischemic and perfused tissues were examined for necrosis, apoptosis, and autophagy. In aim 1, serum IL-6 and IL-6 receptor (IL-6R), gastrocnemius, and myocardial IL-6R were increased following exercise in C57 mice only. Phosphorylated (p) signal transducer and activator of transcription 3 was increased in gastrocnemius and heart in C57 and IL-6-/- mice postexercise, whereas myocardial iNOS and cyclooxygenase-2 were unchanged in the exercised myocardium. Exercise protected C57 EX mice against I/R-induced arrhythmias and necrosis, whereas arrhythmia score and infarct outcomes were higher in C57 SED, IL-6-/- SED, and IL-6-/- EX mice compared with SH. C57 EX mice expressed increased p-p44/42 MAPK (Thr202/Tyr204) and p-p38 MAPK (Thr180/Tyr182) compared with IL-6-/- EX mice, suggesting pathway involvement in exercise preconditioning. Findings indicate exercise exerts cardioprotection via IL-6 and strongly implicates protective signaling originating from the exercised skeletal muscle.

Original languageEnglish
Pages (from-to)H1423-H1433
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume308
Issue number11
DOIs
StatePublished - Jun 1 2015

Keywords

  • Cardioprotection
  • Myocardial infarction
  • Myokine

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