Plasma Matrix Metalloproteinase-9 Response to Downhill Running in Humans

• Published in: International journal of sports medicine 2014-05, Vol.35 (5), p.363-370
• Main Authors: Welsh, M. C., Allen, D. L., Byrnes, W. C.
• Format: Article
• Language: English
• Subjects: Adult; Biological and medical sciences; Biomarkers - blood; Creatine Kinase - blood; Female; Fundamental and applied biological sciences. Psychology; Human physiology applied to population studies and life conditions. Human ecophysiology; Humans; Injuries of the limb. Injuries of the spine; Leg - physiology; Male; Matrix Metalloproteinase 9 - blood; Medical sciences; Muscle Strength - physiology; Muscle, Skeletal - injuries; Physiology & Biochemistry; Running - physiology; Tissue Inhibitor of Metalloproteinase-1 - blood; Traumas. Diseases due to physical agents; Vertebrates: body movement. Posture. Locomotion. Flight. Swimming. Physical exercise. Rest. Sports; Young Adult
• ISSN: 0172-4622; 1439-3964
• DOI: 10.1055/s-0033-1353212

Abstract Matrix metalloproteinase-9 is a proteolytic enzyme capable of degrading proteins of the muscle extracellular matrix. Systemic levels of MMP-9 or its inhibitor, tissue inhibitor of metalloproteinase-1 (TIMP-1), have the potential to serve as blood markers of exercise-induced muscle damage. The purpose of this study was to determine if an eccentrically-dominated task, downhill running (DHR), produces changes in plasma MMP-9 or TIMP-1 and examine the relationship between MMP-9/TIMP-1 levels and indirect indicators of muscle damage. Subjects were sedentary (SED, n=12) or had a history of concentrically-biased training (CON, n=9). MMP-9 and TIMP-1 were measured before (Pre-Ex), immediately after (Post-Ex), and 1-, 2-, 4-, and 7-days post-DHR (−10°), and compared to discomfort ratings, creatine kinase activity and strength loss. At 1-day Post-Ex, discomfort increased (5.6±7.8 to 45.5±19.9 mm; 0–100 mm scale), strength decreased (−6.9±1.6%) and CK increased (162.9±177.2%). MMP-9 was modestly but significantly increased at Post-Ex in both CONC and SED (32.7±33.6%) and at 4-days in SED (66.9±88.1%), Individual responses were variable, however. There were no correlations between MMPs and discomfort ratings, plasma CK or strength. While plasma MMP-9 changes may be detectable in the systemic circulation after DHR, they are small and do not correspond to other markers of damage.