Effects of sodium hyaluronic acid on fibrinolytic factors in the synovial fluid (in vivo)

Twelve patients with osteoarthritis of the knee were administrated hyaluronic acid (HA), and measured for fibrinolytic factors on synovial fluids. It was observed that urokinase-type plasminogen activator (u-PA) activity is enhanced 3 h after administration of HA, and that the activity gradually decreased from the 2nd to the 4th week on the patients whose clinical parameters showed improvement. Antigen of u-PA and PA inhibitor-1 (PAI-1) were increased 3 h after the administration of HA in the cases that improved. However, u-PA antigen gradually decreased from the 2nd to the 4th week similarly to u-PA activity. On the other hand PAI-1 antigen was increased from the 2nd to the 4th week in the improved cases. These results demonstrate that the decrease of fibrinolytic activity in synovial fluid is associated with the improvement of osteoarthritis by treatment with HA.