Evaluation of Akt/mTOR activity in muscle atrophy after rotator cuff tears in a rat model

Xuhui Liu, Sunil K. Joshi, Sanjum P. Samagh, Yu Xuan Dang, Dominique Laron, David H. Lovett, Sue C. Bodine, Hubert T. Kim, Brian T. Feeley

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

Atrophy of the rotator cuff muscles is a factor that complicates the treatment of a massive rotator cuff tear (RCT). However, the molecular mechanisms that govern the development of muscle atrophy after RCTs have not been well defined. The Akt/mammalian target of rapamycin (mTOR) signaling pathway plays a central role in maintaining muscle mass in response to mechanical loading. The role of this pathway in the development of muscle atrophy after a massive RCT remains unknown. The purpose of this study was to investigate the regulation of the Akt/mTOR pathway in the development of muscle atrophy after a RCT and suprascapular nerve (SSN) injury. We evaluated the activity of the Akt/mTOR signaling pathway and how this pathway interacts with two atrophy-related genes, MuRF-1 and MAFbx, in supraspinatus muscles of rats that underwent unilateral complete rotator cuff tendon transection or SSN transection. Akt/mTOR activity was significantly reduced after tendon rupture, but increased after nerve injury. MuRF-1 and MAFbx were only up-regulated following denervation. These results suggest that tendon transection leads to a decrease in protein synthesis with down-regulation of the Akt/mTOR signaling pathway, whereas denervation leads to an increase in protein degradation via up-regulation of expression of MuRF-1 and MAFbx.

Original languageEnglish (US)
Pages (from-to)1440-1446
Number of pages7
JournalJournal of Orthopaedic Research
Volume30
Issue number9
DOIs
StatePublished - Sep 2012

Fingerprint

Muscular Atrophy
Sirolimus
Rotator Cuff
Tendons
Denervation
Muscles
Atrophy
Wounds and Injuries
Proteolysis
Rupture
Up-Regulation
Down-Regulation
Rotator Cuff Injuries
Genes
Proteins

Keywords

  • Akt
  • denervation
  • mTOR
  • muscle atrophy
  • rotator cuff tear

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine

Cite this

Liu, X., Joshi, S. K., Samagh, S. P., Dang, Y. X., Laron, D., Lovett, D. H., ... Feeley, B. T. (2012). Evaluation of Akt/mTOR activity in muscle atrophy after rotator cuff tears in a rat model. Journal of Orthopaedic Research, 30(9), 1440-1446. https://doi.org/10.1002/jor.22096

Evaluation of Akt/mTOR activity in muscle atrophy after rotator cuff tears in a rat model. / Liu, Xuhui; Joshi, Sunil K.; Samagh, Sanjum P.; Dang, Yu Xuan; Laron, Dominique; Lovett, David H.; Bodine, Sue C.; Kim, Hubert T.; Feeley, Brian T.

In: Journal of Orthopaedic Research, Vol. 30, No. 9, 09.2012, p. 1440-1446.

Research output: Contribution to journalArticle

Liu, X, Joshi, SK, Samagh, SP, Dang, YX, Laron, D, Lovett, DH, Bodine, SC, Kim, HT & Feeley, BT 2012, 'Evaluation of Akt/mTOR activity in muscle atrophy after rotator cuff tears in a rat model', Journal of Orthopaedic Research, vol. 30, no. 9, pp. 1440-1446. https://doi.org/10.1002/jor.22096
Liu, Xuhui ; Joshi, Sunil K. ; Samagh, Sanjum P. ; Dang, Yu Xuan ; Laron, Dominique ; Lovett, David H. ; Bodine, Sue C. ; Kim, Hubert T. ; Feeley, Brian T. / Evaluation of Akt/mTOR activity in muscle atrophy after rotator cuff tears in a rat model. In: Journal of Orthopaedic Research. 2012 ; Vol. 30, No. 9. pp. 1440-1446.
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