Dose effects of propofol on hemodynamic and cytokine responses to endotoxemia in rats

Purpose Our previous studies have demonstrated that propofol inhibits hypotension, metabolic acidosis, and cytokine responses and reduces mortality in endotoxemic rats. The purpose of this study was to elucidate whether these beneficial effects of propofol on hemodynamics and cytokine responses were dose related.Methods Forty-eight rats were divided at random among four equal groups: groups S, M, and L received intravenous propofol administration (5, 10, and 20mg·kg^–1·h^–1, respectively) immediately after endotoxin (Escherichia coli endotoxin; 15mg·kg^–1, i.v.) was given. Group E received endotoxin alone. We assessed hemodynamics and plasma cytokine [tumor necrosis factor (TNF)- and interleukin (IL)-6] concentrations for 5h following endotoxin injection.Results Systolic arterial pressure (SAP) was significantly higher at 4 and 5h in groups S and M than in group E (P < 0.05), although SAP decreased progressively in all groups. Endotoxin injection increased the TNF- and IL-6 concentrations in all groups. The increase in TNF- concentrations at 2h was significantly lower in group M than in group E (P < 0.05). On the other hand, the increase in IL-6 concentration at 5h was significantly lower in groups M and L than in group E (P < 0.05).Conclusion The effects of propofol on blood pressure and cytokine responses were influenced by the dose of propofol, although the relationship did not follow simple linearity.