Y. Watanabe¹, R. Yamaguchi¹, S. Iwaki-Egawa¹, Y. Shimamori¹, Y. Fujimoto², H. Matsuno³

Department of Clinical Biochemistry¹ and Department of Biochemistry², Hokkaido College of Pharmacy, Hokkaido; ³Department of Orthopaedic Surgery, Toyama Medical and Pharmaceutical University, Toyama, Japan.

ABSTRACT
Objective
To clarify whether stromelysin-1 and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) are involved in the modulation of activation of progelatinase B in the synovial fluid of patients with rheumatoid arthritis (RA).

Methods
Gelatinases in the synovial fluid of patients with RA were analyzed by gelatin zymography. Concentrations of stromelysin-1 and TIMP-1 were measured using a specific sandwich enzyme linked immunosorbent assay.

Results
Forty-three rheumatoid synovial fluids containing progelatinase B were examined to clarify whether the enzyme was activated by incubation. Incubation at 37°C caused the conversion of progelatinase B to the active form in 22 of the 43 synovial fluids. The levels of both stromelysin-1 and TIMP-1 were determined for each group and the concentration ratio of stromelysin-1/TIMP-1 in the synovial fluids of each group was highly correlated to the activation of progelatinase B.

Conclusion
The balance between the concentrations of stromelysin-1 and of TIMP-1 in the synovial fluid appears to determine whether the progelatinase B molecule causes conversion into the active form.