Transforming growth factor-beta in skeletal muscle strain injury.
Smith-CA; Stauber-WT; Alway-SE; Miller-GR
Med Sci Sports Exerc 2001 May; 33(5)(Suppl 1):S230
The presence of transforming growth factor-beta (TGF-beta) in skeletal muscle has been reported in various muscle disease. In this study, we assess the presence of transforming growth factor-beta in strain-induced muscle injury. Muscle strains were produced by manually stretching (50 repetitions) an activated plantar flexor group through its normal range of motion. Muscle biopsy samples were evaluated 24- and 48- hours after strain injury for the presence of transforming growth factor-beta using immunohistochemical techniques and Western immunoblot analysis. Transcript levels for collagen I, collagen III, and transforming growth factor-beta were assessed using reverse transcriptase polymerase chain reaction (RT-PCR). Immunohistochemical analysis revealed the presence of TGF-beta2 in areas of myofiber injury, whereas TGF-beta1 was in areas of cell necrosis and phagocytosis. RT-PCR indicated increases in collagen I, collagen III, and TGF-beta1 transcripts 24 hours post-strain injury. Increases in collagen I and collagen III transcripts were more pronounced 48 hours after strain injury. Western immunoblot analysis showed no apparent change in TGF-beta2 levels with injury, but an increase in TGF-beta1 levels which was most pronounced 48 hours post-strain injury. These results indicate that TGF-beta1 levels increase after acute strain injury following increases in TGF-beta1 mRNA correlating with increases in collagen I and collagen III transcripts, whereas TGF-beta2 may be a common resident in skeletal muscle awaiting activation.
Muscles; Musculoskeletal-system; Skeletal-system; Injuries; Muscle-tissue; Injury-prevention; Musculoskeletal-system-disorders; Diseases
Disease and Injury: Musculoskeletal Disorders of the Upper Extremities
Medicine and Science in Sports and Exercise
West Virginia University, Morgantown, West Virginia