Expression of matrix metalloproteinase-9 and tumour necrosis factor-alpha in the synovial cells of patients with meniscus tears

Abstract

Background: A meniscus tear is a serious trauma that develops during swinging motion of the fixed foot. Meniscus tears may also be accompanied by divergence of the lateral ligaments of the knee joint.

Materials and methods: We enrolled 45 males and 35 females with meniscal tears in the present study. Patients with local joint pain, swelling, difficulty climbing stairs, patellar creeping, difficulties with daily living activities, local pain on palpation, and walking and running complaints, were included. We performed preoperative magnetic resonance imaging. Synovial fluid (5 mL) was aspirated from the lateral suprapatellar pouch of each knee with meniscal pain with the patient in the supine position. Blood samples were taken and biochemical parameters were analysed. The Harris haematoxylin and eosin staining protocol was used to evaluate tissue samples, and the levels of anti-matrix metalloproteinase (MMP)-9 and anti-tumour necrosis factor alpha (TNF-α) antibodies were measured immunohistochemically.

Results: Increased numbers of lymphocytes and neutrophils, hyperplastic erythrocytes, and fibroblasts were observed in the joint fluid of females. In males, the fibroblast cells were hyperplastic and plasma cell numbers were increased. MMP-9 expression was elevated in plasma cells, fibroblasts, and neutrophils; and TNF-α expression was observed in lymphocytes and polymorphic nucleated cells. We suggest that increased fluid levels in inflamed joints with meniscal tears, and the associated inflammation, disrupt the cartilage matrix and elevate the production of cytokines such as TNF-α and MMP-9 via release from cells such as fibroblasts that synthesise these mediators.

Conclusions: Anti-TNF-α treatment may prevent meniscal tears and prevent or slow the development of osteoarthritis.