Abstract

Objective: α-actin protein and other muscle damage markers were studied in sera of uninjured sportspeople and those with skeletal muscle injury in order to identify a reliable marker for early detection of muscle injuries in sports.

Methods: Blood samples were obtained from 20 sportspeople with skeletal muscle injury and 48 uninjured sportspeople. Immunoassays were performed to determine cardiac troponin I, troponin T, LDH, and myoglobin concentrations. Western blot and densitometry were used to measure α-actin concentrations Skeletal muscle damage was diagnosed according to physical examination and MRI findings and the biochemical criterion of a CK value > 500 IU/L (Rosalki method, Beckman Instruments, S.L.). Results were also compared with previously obtained data on injured and uninjured non-sportspeople.

Results: The mean serum concentration of α- actin was significantly higher in sportspeople with muscle damage (10.49 µg/ml) than in uninjured sportspeople (3.99µg/ml). Sera from the injured sportspeople showed higher levels of α-actin than of troponin or myoglobin. No significant difference in troponin I levels was observed between the groups.

Conclusions: According to these results, α- actin is a new and reliable marker of skeletal muscle damage in sportspeople that can be used for detection of muscle injury. Possible cross-interference between skeletal and cardiac muscle damage can be discriminated by the combined use of α-actin and troponin I. These data suggest that early measurement of α- actin in sportspeople with suspicion of muscle damage will allow them to receive earlier and more effective treatment and to return sooner to the practice of their sport.