Increased IL-1beta expression and myofibroblast recruitment in subacromial bursa is associated with rotator cuff lesions with shoulder stiffness

J Orthop Res. 2008 Aug;26(8):1090-7. doi: 10.1002/jor.20631.


We evaluated whether proinflammatory cytokine expression and myofibroblast recruitment in subacromial bursa was linked to rotator cuff lesions with shoulder stiffness. We analyzed expressions of IL-1beta, IL-6, and TNF-alpha in subacromial bursa and joint fluid collected from 14 patients with cuff tears with stiffness as a study group (Group I) and 14 patients with rotator cuff tears without shoulder stiffness as a control group (Group II) using real-time RT-PCR, immunohistochemistry, and ELISA. Myofibroblast apoptosis in subacromial bursa was analyzed using terminal deoxynucleotidyl transferase -mediated deoxyuridine triphosphate-biotin nick end-labeling (TUNEL) and alpha-smooth muscle actin immunofluorescence staining. Shoulder function was evaluated using the Constant score. Group I had higher mRNA expression (p < 0.001) and immunoreactivities (p < 0.001) of IL-1beta. They also had higher levels of IL-1beta, IL-6, and TNF-alpha in joint fluid. Increased IL-1beta mRNA expression in the subacromial bursa and IL-1beta levels in joint fluid were correlated with a preoperative deficit in shoulder motion (p < 0.001) and preoperative Constant scores (p < 0.001). Immunofluorescence observations showed that Group I subjects had more myofibroblasts (p < 0.001) than Group II. In Group II, a significant correlation was found between apoptotic myofibroblasts and total myofibroblasts (p = 0.002), but not in Group I (p = 0.510). Increased expression of IL-1beta and myofibroblast recruitment in the subacromial bursa in rotator cuff lesions are linked to shoulder stiffness.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acromioclavicular Joint
  • Aged
  • Apoptosis / immunology
  • Bursa, Synovial / immunology*
  • Bursa, Synovial / pathology*
  • Female
  • Fibroblasts / pathology*
  • Fluorescent Antibody Technique
  • Gene Expression / immunology
  • Humans
  • In Situ Nick-End Labeling
  • Interleukin-1beta / genetics*
  • Interleukin-1beta / metabolism
  • Interleukin-6 / genetics
  • Interleukin-6 / metabolism
  • Male
  • Middle Aged
  • RNA, Messenger / metabolism
  • Rotator Cuff Injuries
  • Rotator Cuff* / immunology
  • Rotator Cuff* / pathology
  • Synovial Fluid / immunology
  • Synovial Fluid / metabolism
  • Tumor Necrosis Factor-alpha / genetics
  • Tumor Necrosis Factor-alpha / metabolism


  • Interleukin-1beta
  • Interleukin-6
  • RNA, Messenger
  • Tumor Necrosis Factor-alpha