[Evaluation of the antithrombotic effects of pentoxifylline, acetylsalicylic acid and low molecular weight heparin in the laser model of thrombosis].

Antithrombotic effects of different agents including acetylsalicylic acid (Asprocol/Polfa PL/), pentoxifylline (Agapurin/Spofa CS/) and low molecular weight heparin (Antixarin B. Braun, Melsungen, FRG) were studied in the laser-induced rat thrombosis model. The investigations were carried out on male Wistar rats weighing 200-300 g. Thrombus formation was induced in small mesenteric arteries 25-30 microns; using argon laser. An interference contrast system based on a Leitz Orthoplan microscope for the evaluation of thrombus formation was used. The number of laser injuries needed to induce a defined thrombus proved to be a useful way to quantitate the results in this thrombosis mode. All agents showed dose dependent antithrombotic effect in our laser model. Acetylsalicylic acid (ASA) 2 hours after oral administration markedly inhibited thrombus formation in minimal dose 50 mg/kg, pentoxifylline in dose 10 mg/kg 30 min after i.v. injection and low molecular weight heparin (Antixarin) in dose 0.1 mg/kg, 2 hours, after s.c. injection. Antithrombotic effect of administration of minimal effective doses of ASA (orally) and pentoxifylline (i.v.) lasted longer than 4 hours but less then 6 hours. LMW heparin (Antixarin) in minimal effective dose 0.1 mg/kg after s.c. injection inhibited thrombus formation in small mesenteric vessels for more than 12 hours but less than 24 hours.