Effect of antibiotics on laser-induced thrombus formation in rat mesenteric arterioles

Antibiotics were tested in a thrombosis model, in which thrombi are produced in small rat mesenteric arterioles. An interference contrast system based on a Leitz Orthoplan microscope, was used to visualize thrombus formation. Vascular lesions were produced with a Coherent CR-2 supergraphite ion laser (argon laser) in arterioles of 25-35 microns diameter. Cefmenoxim, cefotaxim (i.v.) and cephalexin orally at doses of 20 and 40 mg/kg and gentamycin 10 and 20 mg/kg (i.v.) had a marked and significant antithrombotic effect. Even more effective were cefoperazon and lamoxactam 20 and 40 mg/kg (i.v.) and tobramycin 10 and 20 mg/kg (i.v.). Azlocillin, cefoxitin, mezlocillin or spectinomycin (20 mg/kg i.v.) and penicillin or piperacillin (50 mg/kg i.v.) also showed a significant antithrombotic effect, which, however, disappeared on doubling of the applied dose.