Abstract
Abstract
Background
Labral tear can be the initiating factor in the onset of hip osteoarthritis (HOA). However, the physiopathology of labral tear is not fully understood. Our aim was to compare synovial tissue inflammatory cytokine levels between patients with labral tear and late-stage HOA.
Methods
Synovial tissue from sites showing the greatest inflammation was harvested from 106 hips from 100 subjects during hip surgery. RNA was extracted, and levels of TNFA, IL1B, IL6 and COX2 mRNA were compared among all patients using real-time PCR. Additionally, we examined whether femoroacetabular impingement (FAI) was associated with elevated levels of inflammatory cytokines in patients with labral tear. To analyze the effects of TNF-α on inflammatory mediators in hip synovial tissue, synovial fibroblasts were extracted from hip synovial tissue of patients with labral tear and late-stage HOA (n = 5 each). Mononuclear cells were extracted from synovial tissue, cultured for 7 days, and stimulated with control or 10 ng/mL human recombinant TNF-α for 1 day. mRNA was extracted from stimulated cells and IL1B, IL6, and COX2 levels were determined using real-time PCR.
Results
TNFA, IL1B, and COX2 expression in synovial tissue were significantly higher in patients with labral tear than late-stage HOA (TNFA, p < 0.001; IL1B, p < 0.001; COX2, p = 0.001). There were no differences in expression between patients with labral tear with and without FAI (TNFA, p = 0.546; IL1B, p = 0.559; IL6, p = 0.599; COX2, p = 0.124). Compared to vehicle control, TNF-α stimulation significantly elevated IL1B, IL6, and COX2 expression in synovial fibroblasts collected from patients with labral tear and late-stage HOA (IL1B, p = 0.043 and p = 0.043; IL6, p = 0.043 and 0.043; COX2, p = 0.043 and p = 0.080, respectively).
Conclusions
TNFA, IL1B, and COX2 expression were elevated in the synovial tissue of patients with labral tear. Further investigations are needed to reveal the relationship between inflammatory cytokine levels and various aspects of labral tear pathology, including pain and the onset and progression of OA.
Publisher
Springer Science and Business Media LLC
Subject
Orthopedics and Sports Medicine,Rheumatology
Reference27 articles.
1. Grant AD, Sala DA, Davidovitch RI. The labrum: structure, function, and injury with femoro-acetabular impingement. J Child Orthop. 2012;6:357–72. https://doi.org/10.1007/s11832-012-0431-1.
2. Eijer H, Hogervorst T. Femoroacetabular impingement causes osteoarthritis of the hip by migration and micro-instability of the femoral head. Med Hypotheses. 2017;104:93–6. https://doi.org/10.1016/j.mehy.2017.05.035.
3. Pitto RP, Klaue K, Ganz R, Ceppatelli S. Acetabular rim pathology secondary to congenital hip dysplasia in the adult. A radiographic study. Chir Organi Mov. 1995;80:361–8.
4. Parmar R, Parvizi J. The multifaceted etiology of acetabular labral tears. Surg Technol Int. 2010;20:321–7.
5. Klennert BJ, Ellis BJ, Maak TG, Kapron AL, Weiss JA. The mechanics of focal chondral defects in the hip. J Biomech. 2017;52:31–7. https://doi.org/10.1016/j.jbiomech.2016.11.056.