Antiplasmin activity in carrageenin-induced inflammation of rats

The significance of inhibitors in the coagulation-fibrinolysis system was examined by inducing experimental inflammation with carrageenin. Fast-acting plasmin inhibitor, alpha 2-plasmin inhibitor (alpha 2-Pl), was recently discovered in human blood and it was stated that such alpha 2-Pl represents the most sensitive and specific inhibitor of plasmin. The possible role of alpha 2-Pl has been studied in detail in vitro and in vivo in relation to the thrombolytic condition and bleeding based on hyperfibrinolysis. However, the significance of alpha 2-Pl has not been clarified for the inflammatory state and diseases. In the present study in order to clarify the possible role of alpha 2-Pl in inflammatory responses, the antiplasmin activity in the plasma and local fluid (exudate) was investigated using an animal model of inflammation. After subcutaneous injection of carrageenin into the dorsum of rats, on day 7 and 21, the antiplasmin activity in the plasma was significantly higher than that in the plasma of non-treated rats (p less than 0.001). However, the antiplasmin activity in the plasma on day 7 was not significantly different from that on day 21. On the other hand, the antiplasmin activity in the exudate on day 21 was significantly lower than that on day 7 (p less than 0.001). Based on ;these results, it is suggested that the antiplasmin in the inflammatory exudate was consumed during the inflammation to form the hard wall of the carrageenin pouch.