Immunolocalization of cytokines and growth factors in subacromial bursa of rotator cuff tear patients.

Inflammation in the subacromial bursa causes pain in patients suffering from rotator cuff tear, with this long-lasting inflammation leading to fibrosis and thickening of the subacromial bursa. Both inflammatory cytokines and mechanical stress, and impingement in the subacromial space, might induce and worsen this inflammation. However, little is known of the mechanism of this inflammation. In this study, we used immunohistological staining to demonstrate the expression of Interleukin-1 beta (IL-1 beta), Tumor necrosis factor alpha (TNF-alpha), transforming growth factor beta (TGF-beta), and basic fibroblast growth factor (bFGF) in subacromial bursa derived from the patients suffering from rotator cuff tear. On the other hand the expression of these inflammatory cytokines and growth factors were little detected only to a small degree in patients with anterior shoulder instability who did not have severe shoulder pain and impingement in the subacromial space. Our findings suggest that those inflammatory cytokines and growth factors may play an important role in inflammation of the subacromial bursa. Controlling the expression of these cytokines and growth factors might be important for treating patients suffering from shoulder pain due to rotator cuff tear.