[Antithrombotic effects of recombinant hirudin in mice and its mechanism].

OBJECTIVE

To investigate the antithrombotic effects of recombinant hirudin and its mechanism.

METHODS

Sixty male Kunming mice were randomly divided into 6 group (=10):control group, model group, aspirin (25 mg/kg) group, recombinant hirudinlow, middle and high dose (0.05, 0.1, 0.2 mg/kg) groups.Except mice in control group, 2.5 mg/kg carrageenan was injected intraperitoneallyto mice in the other groups to produce thrombosis on the mice tail. The mice in aspirin group were administrated intraperitoneally 25 mg/kg aspirin, the mice in recombinant hirudinlow, middle and high dose groups were administrated intraperitoneally 0.05, 0.1, 0.2 mg/kg combinanthirudin, the mice in control group and model group were administrated intraperitoneallynormal saline at the same volume respectively at 24 h, 0.5 h before injecting carrageenan and 24 h after injecting carrageenan. The black tail length of mice and the incidence of black tail were observed at 48h after injection of carrageenan; prothrombin time (PT), activated partial thromboplastin time (APTT), tissue plasminogen activator (t-PA), type-1 plasminogen activator inhibitor (PAI-1), 6-keto-PGF1α, and thromboxane B2 (TXB2) level in mice plasma were determined.

RESULTS

As compared with control group, the mice in model group presented tail thrombosis; PT level in plasma was significantly shortened (<0.01), PAI-1 and TXB2levels in plasma were significantly increased (<0.01), while the t-PA and 6-keto-PGF1α levels in plasma in model group were significantly decreased (<0.01). As compared with model group, the thrombus length in the tail was significantly shortened (<0.05, <0.01), PT level was obviously prolonged (<0.01), and the plasma levels of PAI-1 and TXB2 were significantly decreased (<0.01), while the plasma levels of t-PA and 6-keto-PGF1α were significantly increased (<0.01)in the mice of recombinant hirudin low dose, middle dose, high dose groups and aspirin group. As compared with aspirin group, the thrombus length in the tail was significantly increased (<0.05), PT level was obviously shortened (<0.01), and the plasma levels of PAI-1 and TXB2 were significantly increased (<0.01)in the mice of recombinant hirudin low dose group; the plasma level of 6-keto-PGF1α was significantly decreased (<0.01, <0.05) in the mice of recombinant hirudin low dose and middle dose groups; the plasma levels of PAI-1 and TXB2 were significantly increased (<0.01, <0.05)in the mice of recombinant hirudin middle dose group.

CONCLUSIONS

The recombinant hirudin can fight against thrombosis, its antithrombotic mechanisms may be related to its influence on the exogenous coagulation system and the promotion of fibrinolysis function.