The Effect of Endotoxin on Haemostasis in Normal and Leukemic Rats

Platelet count, fibrinogen and antithrombin levels were studied in normal rats (group A), in rats with the experimental rat leukemia L 5222 in an early phase (group B) and in a final phase (group C) of the disease. The animals were randomized and treated with o.5 mg endotoxin or placebo as a single i.v.injection. Four hours later blood samples were taken for laboratory tests. The results were as follows: 1. Groups A and B did not differ in the laboratory parameters under investigation 4 hours after injection of saline as a placebo. 2. Leukemic rats of group C treated with saline had significantly elevated levels of fibrinogen and antithromin as well as reduced platelet count compared to their normal counterparts. 3. The injection of endotoxin resulted in a comparable decrease of platelets in normal and leukemic animals. 4. The injection of endotoxin led to a decrease of fibrinogen levels in all groups. The most pronounced decrease was observed in group B, while there was only a slight fall in group C. The antithrombin levels of group A and B were not influenced by endotoxinaemia. The elevated level of antithrombin in group C, however, was completely normalized after a single injection of endotoxin.It can be concluded from these results that the haemostatic system of rats in the early phase of the leukemia L 5222 is more susceptible to endotoxin than that of normal controls. Possibly due to marked elevated levels of antithrombin rats in the final phase of the disease seem to be protected against the aggravation of the haemostatic defect by endotoxin.