Shoulder pain and intra-articular interleukin-8 levels in patients with rotator cuff tears.
OBJECTIVE
Rotator cuff disease (RCD) is one of the most common disorders in the shoulder joint and causes joint pain and functional disability. In this study, we investigated the associations among cytokine levels and clinical symptoms in patients with RCD.


METHODS
Joint fluid specimens of the shoulder joint were obtained from 38 patients with RCD before arthroscopic surgery. The levels of inflammatory cytokines, including interleukin (IL)-1β, IL-6 and IL-8, were evaluated using enzyme-linked immunosorbent assay kits, and the associations between these cytokine levels and the clinical symptoms were determined. A multiple linear regression analysis was performed to identify the parameters accounting for the visual analogue scale (VAS) score at rest.


RESULTS
IL-8 level was correlated with IL-6 (r = 0.434, P = 0.006) and IL-1β (r = 0.575, P < 0.001) levels. The cuff tear size was inversely correlated with the VAS score at rest. A multiple stepwise linear regression analysis revealed that the VAS score at rest could be explained by the VAS score at night, the VAS score during movement and the intra-articular IL-8 level (adjusted R² = 0.544, P < 0.001). The intra-articular IL-8 level is associated with resting pain in rotator cuff tear patients.


CONCLUSIONS
These results suggest that an increased concentration of IL-8 is associated with resting pain in rotator cuff tear patients.
Department of Orthopaedic Surgery, Gunma University Graduate School of Medicine, Maebashi, Japan.
Koichi
K
Okamura
Department of Physical Therapy, Takasaki University of Health and Welfare, Takasaki, Gunma, Japan.
Tsutomu
T
Kobayashi
Department of Orthopaedic Surgery, Gunma University Graduate School of Medicine, Maebashi, Japan.
Atsushi
A
Yamamoto
Department of Orthopaedic Surgery, Gunma University Graduate School of Medicine, Maebashi, Japan.
Hitoshi
H
Shitara
Department of Orthopaedic Surgery, Gunma University Graduate School of Medicine, Maebashi, Japan.
Toshihisa
T
Osawa
Department of Orthopaedic Surgery, Gunma University Graduate School of Medicine, Maebashi, Japan.
Tsuyoshi
T
Ichinose
Department of Orthopaedic Surgery, Gunma University Graduate School of Medicine, Maebashi, Japan.
Kenji
K
Takagishi
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001182:Arthroscopy; D015415:Biomarkers / Q000032:analysis; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D053583:Interleukin-1beta / Q000032:analysis; D015850:Interleukin-6 / Q000032:analysis; D016209:Interleukin-8 / Q000032:analysis*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D000070636:Rotator Cuff Injuries / Q000175:diagnosis / Q000276:immunology* / Q000601:surgery; D012785:Shoulder Joint / Q000276:immunology* / Q000601:surgery; D020069:Shoulder Pain / Q000175:diagnosis / Q000276:immunology* / Q000601:surgery; D013582:Synovial Fluid / Q000276:immunology*; D015854:Up-Regulation
D015415:Biomarkers; C508606:CXCL8 protein, human; C508585:IL1B protein, human; C508600:IL6 protein, human; D053583:Interleukin-1beta; D015850:Interleukin-6; D016209:Interleukin-8
cytokine; interleukin; rotator cuff disease; shoulder disorder; shoulder pain