Demonstration of flow and platelet dependency in a ferric chloride-inducedmodel of thrombosis

Further to characterize the processes involved in the FeCl3-induced thrombo sis model, we determined the effect of aspirin, heparin, hirudin, trans-4-( aminomethyl) cyclohexane carboxylic acid (AMCHA), thrombocytopenia, and flo w modifications on time to occlusion (TTO) and thrombus weight (TW) in the rat carotid artery. Aspirin, from 3 to 100 mg/kg, showed no dose-response r elation for either TTO or TW and did not significantly affect ex vivo plate let aggregation. Heparin, at doses that significantly increased the activat ed partial thromboplastin time (APTT), dose-dependently increased the TTO o f animals that showed an occlusion during the monitoring period and also re duced the TW. Hirudin required constant infusion to prevent occlusion and r educe the TW, when the APTT was also significantly increased. AMCHA did not affect the TW but reduced the TTO. Animals made thrombocytopenic by the us e of antiplatelet serum did not occlude during the monitoring period, and t he TW was significantly reduced. Changes in flow showed that the TTO was no t affected, but the TW showed an inverse correlation with average flow. The results obtained for platelet depletion and flow modifications expand on p revious findings with this model and support the physiological relevance of the model.