ABSTRACT
BACKGROUND:Matrix metal oproteinases (MMPs) have been shown to break the balance between the production and degradation of extracel ular matrix by degrading col agen, gelatin, elastin and other macromolecules, which is the leading cause of bone and cartilage damage in rheumatic arthritis. OBJECTIVE:To determine the expression levels of MMP-2 and MM-9 in the rabbit knee osteoarthritis cartilage, and to analyze whether they are related to the early MRI performance. METHODS:Fifty healthy Japanese white rabbits free from osteoarthritis were enrol ed and randomly divided into control group (n=10) and model group (n=40). The anterior and posterior cruciate ligament amputation was adopted to establish the model of osteoarthritis. Subsequently, MRI examination and the expression levels of MMP-2 and MMP-9 were detected at 1, 3, 5 and 7 weeks (n=10 at each time point), respectively. RESULTS AND CONCLUSION:MRI examination showed that more damaged cartilage appeared with time in the rabbit model of osteoarthritis, and significantly different from MRI classification (P<0.05). The expression levels of MMP-2 and MMP-9 mRNA in the model group were always significantly higher than those in the control group (P<0.05);MMP-2 level reached the highest at 3 weeks after modeling (P<0.01), and then presented a slight decline;MMP-9 level peaked at 5 weeks after modeling (P<0.01) and slightly decreased at 7 weeks. MRI classification of cartage injury and expressions of MMP-2 (R2=0.119, P=0.119) and MMP-9 (R2=0.466, P=0.466) were shown to have the correlation. These results il ustrate that the serum levels of MMP-2 and MMP-9 are related to the early destruction of articular cartilage in patients with osteoarthritis, and can be used as predictors for early osteoarthritis.