Thrombolytic effect of lonomin V in a rabbit jugular vein thrombosis model

Thrombolytic efficacy of lonomin V (LV), a protein isolated from Lonomia ac helous caterpillars haemolymph, administered either as a single intravenous bolus or as a continuous infusion, was evaluated in a rabbit jugular vein thrombosis model, and compared with those of single-chain tissue-type plasm inogen activator (sct-PA) and two-chain urokinase-type plasminogen activato r (tcu-PA). As a bolus LV, at doses of 100 000 IU/kg body weight (bw) produ ced an activator-induced thrombolysis (AIL) of 50.94% +/- 12.4 compared wit h 14.4% +/- 10.8 for tcu-PA at the same dose. As a continuous infusion at d oses of 200 000 IU/kg bw LV produced an AIL of 45.8%, whereas sct-PA and tc u-PA produced an AIL of 69.9 and 33.7%, respectively. Fibrinogen, plasminog en and alpha -2-antiplasmin levels decreased significantly with the higher doses of LV, sct-PA, and tcu-PA. Factor XIII levels were significantly redu ced in a dose-dependent manner only with LV. In conclusion, LV produces a d ose-dependent thrombolysis in combination with a decrease in factor XIII ac tivity. (C) 2001 Lippincott Williams & Wilkins.