Interleukin‐1‐induced subacromial synovitis and shoulder pain in rotator cuff diseases

Open Access
Publisher Website
Google Scholar
Abstract
Objective. To determine the relationship between the expression of interleukin‐1β (IL‐1β) and IL‐1 receptor antagonists (IL‐1ra) in the subacromial bursa and shoulder pain in rotator cuff diseases. Methods. Synovial specimens were analysed using various methods including reverse transcriptase–polymerase chain reaction (RT–PCR), immunohistochemistry and in situ RT–PCR. Thirty‐nine patients with rotator cuff diseases were candidates. The degree of their shoulder pain was evaluated using a visual analogue scale. Results. The mRNA expression levels of the cytokines were significantly correlated with the degree of pain [IL‐1β: r=0.782; secreted IL‐1ra (sIL‐1ra): r=0.756; intracellular IL‐1ra (icIL‐1ra): r=0.806, Pin situ RT–PCR analysis indicated that both synovial lining and sublining cells produce IL‐1β, while synovial lining cells predominantly produce icIL‐1ra and sublining cells secrete sIL‐1ra. Conclusions. The differential regulation of the two forms of IL‐1ra mRNAs may play an important role in shoulder pain in rotator cuff diseases, regulating IL‐1‐induced subacromial synovitis.