Changes in the Concentration of Tissue Inhibitor of Metalloproteinase-2 and Matrix Metalloproteinase-2 in the Synovial Fluid in Canine Stifle Osteoarthritis Secondary to Medial Patellar Luxation
This study was performed to investigate the concentration of tissue inhibitor of metalloproteinase-2 (TIMP-2) and matrix metalloproteinase-2 (MMP-2) in the synovial fluid (SF) of normal and osteoarthritis (OA) stifles.
For induction of OA, MPL was surgically produced in the left stifle joint in 24 skeletally mature mixed small breed dogs (age 2 to 6 years, and weight 2.8 to 9 kg) by placing purse string sutures around the parapatellar fibrocartilage and anchoring the patella with the fabellar ligament, and by medial imbrication and lateral release. The animals were randomly allocated in 2 groups; sham group (n=12), the right stifle was sham operated and control group (n=12) having intact right stifle. Physical and radiographic examinations of the stifles were performed at every 1.5 months intervals during one-year experimental period. The SF was aspired from both stifles preoperatively and postoperatively at every 1.5 month intervals and was subjected to assay MMP-2 and TIMP-2. One dog was euthanatized at every 3 months and tissue samples from both stifles were collected for histopathology.
The clinical signs of osteoarthritis were obvious in the experimental dogs by 12 weeks of the surgical induction of MPL, which was also evidenced in histopathology of the tissue samples. The level of MMP-2 in the SF of the index stifles significantly increased (p<0.05) and that of the TIMP-2 significantly decreased (p<0.05) 3 months after induction of OA.
The TIMP-2 and MMP-2 assay can play important roles for the diagnosis of early phases of osteoarthritis in the dog.