Aim: To explore the effects of ketamine on hemo-dynamics, plasma proinflammatory cytokine (TNF-alpha and IL-6) levels and nuclear factor kappa B (NF-kappaB) activation during polymicrobial sepsis.
Methods: Male Sprague-Dawley rats were subjected to cecal ligation and puncture (CLP) or sham operation. The rats were randomly assigned into four equal groups: sham CLP group, CLP group, ketamine (KT) I group and KT II group. Thirty minutes before CLP, ketamine (5 mg/kg per hour and 10 mg/kg per hour, respectively) was infused continuously through the left femoral vein cannula in KT I group or KT II group. Sham CLP group and CLP group received 0.9% saline only (5 mL/kg per hour). The right femoral artery was cannulated to monitor mean arterial pressure (MAP) and heart rates (HR),and draw blood samples. The proinflammatory cytokine (TNF-alpha and IL-6) levels of plasma were measured using enzyme-linked immunosorbent assays (ELISA). The hepatic NF-kappaB activation was determined by Western blot and HPIAS 2000 image analysis system. Twenty hours after CLP, the rats were killed by right femoral artery phlebotomization.
Results: CLP produced progressive hypotension, and a first increase followed by a decrease in HR. The hypotension was prevented, and the HR was slightly steady in ketamine treated rats. TNF-alpha levels of plasma reached a peak value at 2 h after CLP. Ketamine (KT I group or KT II group) caused a significant decrease compared with CLP group at 2, 5 and 9 h time points after CLP (14.3 +/- 1.9 vs 4.3 +/- 0.9, 9.7 +/- 1.4 vs 4.3 +/- 0.9; 9.3 +/- 1.5 vs 4.3 +/- 0.9, 8.7 +/- 1.4 vs 4.3 +/- 0.9; 6.0 +/- 1.5 vs 5.0 +/- 1.7, 5.3 +/- 0.8 vs 5.0 +/- 1.7; P < 0.01, respectively). The IL-6 levels of plasma firstly ascended and then descended in CLP group, and reached a peak value at 9 h after CLP. Ketamine (KT I group or KT II group) caused a significant decrease compared with CLP group at 5, 9 or 20 h after CLP (135.0 +/- 52.6 vs 60.0 +/- 16.3, 112.5 +/- 52.6 vs 60.0 +/- 16.3; 410.0 +/- 68.7 vs 62.5 +/- 12.5, 250.0 +/- 28.0 vs 62.5 +/- 12.5; 320.0 +/- 25.9 vs 52.5 +/- 10.1, 215.0 +/- 44.6 vs 52.5 +/- 10.1; P < 0.05, respectively). The IL-6 levels of plasma in KT II group were lower than those of KT I group at 9 h after CLP (250.0 +/- 28.0 vs 410.0 +/- 68.7; P < 0.05). In addition, CLP increased hepatic NF-kappaB expression compared with sham CLP. Ketamine suppressed NF-kappaB activation in a dose-dependent manner at 4 h after CLP (237.7 +/- 3.5 vs 246.9 +/- 3.1; P < 0.05).
Conclusion: Ketamine stabilizes the hemodynamics, attenuates the proinflammatory cytokine responses, and inhibits hepatic NF-kappaB activation. These findings suggest that ketamine has protective effects against polymicrobial sepsis in rats.