Characteristics of myogenic response and ankle torque recovery after lengthening contraction-induced rat gastrocnemius injuryReport as inadecuate

Characteristics of myogenic response and ankle torque recovery after lengthening contraction-induced rat gastrocnemius injury - Download this document for free, or read online. Document in PDF available to download.

BMC Musculoskeletal Disorders

, 13:211

First Online: 30 October 2012Received: 21 May 2012Accepted: 22 October 2012


BackgroundAlthough muscle dysfunction caused by unfamiliar lengthening contraction is one of most important issues in sports medicine, there is little known about the molecular events on regeneration process. The purpose of this study was to investigate the temporal and spatial expression patterns of myogenin, myoD, pax7, and myostatin after acute lengthening contraction LC-induced injury in the rat hindlimb.

MethodsWe employed our originally developed device with LC in rat gastrocnemius muscle n = 24. Male Wistar rats were anesthetized with isoflurane aspiration rate, 450 ml-min, concentration, 2.0%. The triceps surae muscle of the right hindlimb was then electrically stimulated with forced isokinetic dorsi-flexion 180°-sec and from 0 to 45°. Tissue contents of myoD, myogenin, pax7, myostatin were measured by western blotting and localizations of myoD and pax7 was measured by immunohistochemistry. After measuring isometric tetanic torque, a single bout of LC was performed in vivo.

ResultsThe torque was significantly decreased on days 2 and 5 as compared to the pre-treatment value, and recovered by day 7. The content of myoD and pax7 showed significant increases on day 2. Myogenin showed an increase from day 2 to 5. Myostatin on days 5 and 7 were significantly increased. Immunohistochemical analysis showed that myoD-positive-pax7-positive cells increased on day 2, suggesting that activated satellite cells play a role in the destruction and the early recovery phases.

ConclusionWe, thus, conclude that myogenic events associate with torque recovery after LC-induced injury.

KeywordsMuscle injury Eccentric contraction Regeneration Myogenic factor Electronic supplementary materialThe online version of this article doi:10.1186-1471-2474-13-211 contains supplementary material, which is available to authorized users.

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Author: Hongsun Song - Eisuke Ochi - Kihyuk Lee - Kenji Hiranuma - Koichi Nakazato


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