[Effect of propofol on spinal excitatory amino acid accumulation]

To investigate the protective effect of propofol on ischemia/reperfusion induced spinal cord injury in rabbits and its influence on excitatory amino acid (EAA).

Sixty New Zealand white rabbits weighing 2.0-2.5 kg, half males and half females, were selected. The infrarenal circumaortic clamping model was used. And 6 mL/kg different fluids were continuously infused through a catheter into the aorta distal to the clamping site at a speed of 12 mL/(kg x h) during the 30 minutes ischemia period. According to the different infusing liquids, the rabbits were randomized into 6 groups (n = 10 per group): group A, normal saline; group B, 10% intralipid; group C, propofol 30 mg/kg; group D, propofol 40 mg/kg; group E, propofol 50 mg/kg; group F, propofol 60 mg/kg. At 0, 6, 24, and 48 hours after reperfusion, neurologic outcomes were scored on a Tarlov scale system. At 48 hours after reperfusion, the number of normal neurons in the anterior spinal cord was counted, and concentration of EAA in the lumbar spinal cord was measured by high performance liquid chromatography.

The neuroethological score was better in groups C, D, E and F than that of groups A and B (P < 0.05), the score of group E was the highest (P < 0.05), and there was no significant difference between group A and group B (P > 0.05). The number of normal neurons in the anterior spinal cord of groups C, D, E and F was greater than that of groups A and B (P < 0.05), and group E was greater than groups C, D and F (P < 0.05). The concentration of EAA in groups A, B, C, D, E and F was greater than that of normal tissue, the group E was the lowest (P < 0.05), the groups A and B were the highest (P < 0.05), and there was no significant difference between group A and group B (P > 0.05). Concentrations of glutamate and aspartic acid were negatively correlated to normal neuron numbers in the anterior spinal cord and neuroethological scores 48 hours after reperfusion, and the corresponding correlation coefficient was -0.613, -0.536, -0.874 and -0.813, respectively (P < 0.01).

Propofol can significantly inhibit the accumulation of EAA in spinal cord and provide a protective effect against the ischemia/reperfusion injury induced spinal cord in rabbits.