Endotoxin tolerance phenomenon in horses. Observation of changes in the platelet count and fibrinogen concentration

The subjects were 8 clinically healthy Polish Primitive Horses at 2-9 years of age. The horses were given E.coli LPS four times, in a dose of 0.1 μg/kg.b.w.; 3 times at 24 hour intervals (LPS-1 , LPS-2, LPS-3 ), and one week after the last infusion (LPS-4). The result analysis indicated that the applied endotoxin dose caused development of tolerance mechanisms related to the platelet count. This phenomenon did not concern changes in fibrinogen concentration. The relatively high sensitivity of horses to LPS may be connected with short duration of endotoxin tolerance in this species.