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

39 Scopus citations

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

Keywords

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

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine

Fingerprint Dive into the research topics of 'Evaluation of Akt/mTOR activity in muscle atrophy after rotator cuff tears in a rat model'. Together they form a unique fingerprint.

  • Cite this

    Liu, X., Joshi, S. K., Samagh, S. P., Dang, Y. X., Laron, D., Lovett, D. H., Bodine, S. C., Kim, H. T., & 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