Effect of N‐2‐mercaptopropionyl glycine in postfatigue tension in avian skeletal muscle

Abstract

Use of antioxidants can reduce the development of fatigue and reverse the decline of force induced by ROS. It have been reported that N‐2‐mercaptopropionyl glycine (MPG), a potent cell permeable ROS scavenger, prevents ischemic damage in heart during exercise; a process analogous in skeletal muscle fatigue, which also involves triggering of several signaling pathways, among those found the production of ROS. Thus, the purpose of this study was to determine the effect of MPG during fatigue. Anterior Latissimus Dorsi muscle of chicks was dissected and mounted on an experimental recording chamber by placing the distal end of the muscle to the hook of a mechanic‐electric transducer (Grass FT03), which through an amplifier and a analog‐digital interface (Digidata 1322A) allowed to acquire the muscle tension generated in a computer and a software of data acquisition (AXOTAPE, pCLAMP 9.2). We performed a fatigue protocol by twitches (100 V, 300 ms , 0.5 Hz). Once force decreased by 60 %, MPG was applied for 6 min (500 uM, 1 mM and 1.5 mM). The mayor effect observed by administration of MPG was at 1 mM on single twitch post‐fatigue tension. The post‐fatigue tension increased to 20.18 ± 5.92 % in peak tension (p=0.034), while in total tension was 39.95 ± 14.56 % (p= 0.046) compared to fatigued condition. Results suggest that the removal of certain amount of ROS can improve force, but it is also necessary a quantity of ROS for its normal function.