Skeletal muscle injury induced by eccentric muscle action: muscle proteins as markers of muscle fiber injury.
Muscular overuse after high force eccentric muscle action is associated with structural damage of the contractile apparatus that can be observed as Z-line steaming and myofibrillar disruption. Mechanical stress is the major contributing factor for inducing muscle injury, which initiates a cascade of processes resulting in skeletal muscle damage. Disturbances in Ca2+ homeostasis with elevated intracellular [Ca2+] activates the nonlysomal cysteine protease, calpain. Calpain is assumed to play an important role in triggering the response of skeletal muscle protein breakdown, of inflammatory changes, and of regeneration processes in response to eccentric muscle action. The inflammatory response is attributed to changes in hormone and cytokine levels in blood and skeletal muscle. To assess the amount of skeletal muscle damage, plasma CK activity and plasma myoglobin levels have been widely used as markers for muscle injury. As the cytosolic proteins do not necessarily reflect the amount of structural damage, structurally bound proteins such as myosin heavy chains and troponin have been investigated. This paper briefly reviews the cascade of events causing muscle cell injury after unaccustomed eccentric muscle action and the potential of muscle proteins as markers of skeletal muscle damage.
Sorichter
S
S
Universitätsklinikum Freiburg, Abteilung für Pneumologie, Germany.
Puschendorf
B
B
Mair
J
J
D000818:Animals; D015415:Biomarkers; D002352:Carrier Proteins / Q000378:metabolism; D003402:Creatine Kinase / Q000378:metabolism; D015444:Exercise / Q000502:physiology; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D006801:Humans; D018485:Muscle Fibers, Skeletal / Q000378:metabolism; D009124:Muscle Proteins / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000293:injuries* / Q000378:metabolism; D018996:Myelin P2 Protein / Q000378:metabolism; D009211:Myoglobin / Q000378:metabolism; D018995:Myosin Heavy Chains / Q000378:metabolism; D009363:Neoplasm Proteins; D005082:Physical Exertion / Q000502:physiology; D019210:Troponin I / Q000378:metabolism; D025521:Tumor Suppressor Proteins
D015415:Biomarkers; D002352:Carrier Proteins; C107608:FABP7 protein, human; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D009124:Muscle Proteins; D018996:Myelin P2 Protein; D009211:Myoglobin; D009363:Neoplasm Proteins; D019210:Troponin I; D025521:Tumor Suppressor Proteins; D003402:Creatine Kinase; D018995:Myosin Heavy Chains