Changes of serum cytokine activities and other parameters in dogs with experimentally induced endotoxic shock

To study the relationship of changes of cytokines in endotoxic shock, serum tumor necrosis factor (TNF), interleukin (IL)-1 and IL-6 like activities, together with physiologic and hemodynamic responses, were examined in dogs before and after intravenous administration of lipopolysaccharide (LPS) purified from Escherichia coli in a dose of 500 micrograms/kg of body weight. The blood endotoxin concentration increased significantly at 30 min after LPS administration, and maintained high levels for 24 hr. Red blood cell counts; hemoglobin concentration and hematocrit values increased at 30 min, and these high values persisted for 24 hr. The platelet count decreased significantly at 30 min, then showed a tendency to recover, but decreased again at 24 hr. Cardiac output, cardiac index and mean arterial pressure showed transient, significant decreases at 15 min, and then returned to the baseline levels by 24 hr. TNF-like activities increased at 30 min, while IL-1-like activities did so between 30 and 60 min. The former reached the maximal levels at 2 hr and the latter at 1.5 hr. Both activities were then hardly detectable from 6 to 24 hr. IL-6-like activities elevated at 1 hr with the peak at 1.5 hr, and remained high until 24 hr.