title: Dexamethasone and recovery of contractile tension after a muscle injury.
abstract: Muscle strains, frequently the result of a lengthening contraction, sometimes are treated with corticosteroids. We tested whether an injection of dexamethasone administered soon after muscle injury would minimize inflammation and facilitate the recovery of contractile tension. We applied one eccentric contraction on the tibialis anterior of 76 rats, which were randomly assigned to one of three groups: sham-injured plus dexamethasone, injured plus vehicle, and injured plus dexamethasone. Electrophysiology, histology, and reverse transcription-polymerase chain reaction were used to study the relation between contractile tension, inflammation, and the expression of inflammatory molecules. The single eccentric contraction led to a reversible muscle injury characterized initially by reduced contractile tension and inflammation. The dexamethasone injection reduced the expression of interleukin-1beta and transforming growth factor-beta1 compared with injured vehicle-injected controls and led to a transient improvement of contractile tension 3 days after the injury. No adverse effects were seen for as much as 3 weeks after the dexamethasone injection. The data indicate that one dose of dexamethasone administered soon after muscle strain may facilitate recovery of contractile tension without causing major adverse consequences in this experimental model.
authors.affiliation: Department of Physical Therapy and Rehabilitation Science, University of Maryland School of Medicine, Baltimore, MD, USA.
authors.forename: Marc
authors.initials: M
authors.lastname: Hakim
authors.forename: William
authors.initials: W
authors.lastname: Hage
authors.forename: Richard M
authors.initials: RM
authors.lastname: Lovering
authors.forename: Claude T
authors.initials: CT
authors.lastname: Moorman
authors.forename: Leigh Ann
authors.initials: LA
authors.lastname: Curl
authors.forename: Patrick G
authors.initials: PG
authors.lastname: De Deyne
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D015415:Biomarkers; D003907:Dexamethasone / Q000494:pharmacology*; D007375:Interleukin-1 / Q000235:genetics; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D018482:Muscle, Skeletal / Q000293:injuries* / Q000502:physiology; D009220:Myositis / Q000188:drug therapy / Q000473:pathology / Q000503:physiopathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D020127:Recovery of Function / Q000187:drug effects; D013180:Sprains and Strains / Q000188:drug therapy* / Q000473:pathology / Q000503:physiopathology; D016212:Transforming Growth Factor beta / Q000235:genetics; D053773:Transforming Growth Factor beta1
chemical_list: D000893:Anti-Inflammatory Agents; D015415:Biomarkers; D007375:Interleukin-1; C508962:Tgfb1 protein, rat; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D003907:Dexamethasone