The Effects of Eccentric Contraction Preconditioning on Ischemia- Reperfusion Injury in Mouse Skeletal Muscle

Abstract

2013 Endurance exercise-induced increase in cardiac heat shock protein (HSP) is associated with reductions in ischemia-reperfusion (I-R) injury in the heart. Eccentrically biased exercise is associated with increases in skeletal muscle HSP and protection from exercise-induced muscle injury in subsequent bouts. PURPOSE: To ascertain whether preconditioning of mouse anterior crural muscle with eccentric contractions protects the muscle against I-R injury. The left anterior crural muscles of mice performed either 150 passive concentric or 150 eccentric contractions in vivo. METHODS: I-R injury was induced 2 wks later by placing a tourniquet around the left upper thigh for 2 h. Peak isometric torque as a function of stimulation frequency (20–400 Hz) was measured immediately before and after the preconditioning exercise and I-R injury, and at 7, 14 and 21 d after ischemia. At 21 d, the injured and contralateral control EDL muscles were dissected free for in vitro contractile measurements. RESULTS: Peak isometric torques (20–400 Hz) were decreased immediately (91–52%) after eccentric contraction-induced injury. Immediately prior to I-R injury there were no differences between groups for peak isometric torques at frequencies (20–400 Hz). I-R injury resulted in significant, and similar, reductions in peak isometric torques in both groups immediately after injury (99–100%), and at 7 d (84–90%), 14 d (40–48%) and 21 d (30–35%). There were no differences between groups for peak isometric twitch and tetanic forces, specific force, and wet weight for injured EDL muscles 21 d after I-R injury. CONCLUSION: Preconditioning mouse skeletal muscle with a single bout of eccentric contractions does not appear to protect the muscle against I-R injury.