Correlation of the expression of the inflammatory cytokines and the pathological degree in patients with knee osteoarthritis / 中国组织工程研究

ABSTRACT

BACKGROUND: In the development of osteoarthritis, the mechanism underlying cartilage damage is still unclear. Matrix metalloproteinases have been shown to play important roles in cartilage matric degradation. OBJECTIVE: To observe the correlation between the expression of matrix metalloproteinase 3, tissue inhibitor of metalloproteinase-1 and the pathological degree in knee osteoarthritis. METHODS: The study was approved by the Ethics Committee of Shenyang Orthopedic Hospital. The tibial plateaus of 40 patients with knee osteoarthritis who underwent total knee arthroplasty were collected, and all patients signed the informed consents. The classification of osteoarthritis was evaluated according to Kellgren-Lawrence (KL) scale system 11 cases of KL grade 2, 15 cases of KL grade 3, and 14 cases of KL grade 4. Control group contained six cases. Samples received hematoxylin-eosin staining. The pathological changes of knee osteoarthritis cartilage were evaluated by Mankin score. Immunohistochemical staining was used to detect the contents of matrix metalloproteinase 3 and tissue inhibitor of metalloproteinase-1 in cartilage. RESULTS AND CONCLUSION: (1) Hematoxylin-eosin staining results showed that in the control group, the layer of cartilage was thick, and there were abundant chondrocytes that arranged regularly. The subcutaneous layer of cartilage in the KL grade 2 group was rugged, and fissure was observed occasionally. Fibrosis of cartilage layer was visible in the KL grade 3 group, and the chondrocytes arranged in disorder. In the KL grade 4 group, the structure of cartilage layer was lost, and there were few chondrocytes that arranged irregularly. (2) Immunohistochemical staining results showed that the expression level of matrix metalloproteinase 3 in the osteoarthritis group was significantly higher than that in the control group. The expression level of matrix metalloproteinase 3 was on a rise in the KL grade 2, 3 and 4 groups (all P < 0.05). The expression level of tissue inhibitor of metalloproteinase-1 in the osteoarthritis group was significantly lower than that in the control group. The expression level of tissue inhibitor of metalloproteinase-1 was on a descent in the KL grade 2, 3 and 4 groups (all P < 0.05). (3) There was significantly positive correlation between matrix metalloproteinase 3 expression level and Mankin score (r=0.899, P < 0.001), and tissue inhibitor of metalloproteinase-1 expression level was negatively correlated with Mankin score (r=-0.903, P < 0.001). There was significantly negative correlation between tissue inhibitor of metalloproteinase-1 expression level and matrix metalloproteinase 3 expression level (f=-0.881, P < 0.001). (4) These results indicate that in the articular cartilage of patients with osteoarthritis, the expression levels of matrix metalloproteinase 3 and tissue inhibitor of metalloproteinase-1 are correlated with the pathological changes, which can be used as an effective index to evaluate the progress of knee osteoarthritis.