Haemostatic imbalance following carrageenan-induced rat paw oedema

Carrageenan-induced rat paw oedema is a widely used model to investigate the physiopathology of an acute local inflammation. Recently, much attention has been focused on the link between haemostasis and inflammation, and on the impact that inflammation might have on thrombotic events. It is known that the systemic response to inflammation is the "acute phase reaction" that represents a highly complex reaction of the organism to a variety of injuries, aimed to restore homeostasis; one important feature of the acute phase reaction is the hepatic synthesis of proteins involved in the coagulation cascade. Much attention has been focused on the role that systemic inflammation might have on thrombotic events, while there is not much information on the role played by an acute local inflammation on haemostasis, that can lead toward a pro-thrombotic state. The present study was conducted to evaluate the haemostatic balance in the early and the late phase of carrageenan-induced rat paw oedema; i.e. at 3 h, when paw inflammation is maximally expressed, and 24 h following carrageenan injection, when there is an almost complete absence of local inflammatory symptoms. We found that in inflamed animals, 24 h following oedema induction, there was an increase in plasma fibrinogen levels, antithrombin III activity and serum interleukin-6 levels, concomitant to a shortened prothrombin time and to an increased platelet responsiveness to ADP. Furthermore, in inflamed tissues at 3 h there was an increase in antithrombin III proteic expression. Our results demonstrate that a haemostatic imbalance occurs following carrageenan-induced rat paw oedema.