[Effect of propofol aortic infusion on ischemia-reperfusion spinal cords of rabbits].

OBJECTIVE: To reveal the mechanism of propofol aortic infusion in protecting ischemia-reperfusion spinal cords through detecting the IL-6 levels in the spinal cords and observing the neurological functioning.

METHODS: Fifty six healthy New Zealand White rabbits were randomly allocated into three groups, 4 in the control group, 26 in the Saline infusion group and 26 in the Propofol infusion group. The spinal cord ischemia was induced by infrarenal aorta occlusion for 30 minutes. Propofol were infused through aorta distal to the occlude sites of the rabbits in the Propofol infusion group continuously with a pump at a rate of 50 mg/kg x 30 min. The same volume of Saline were infused in the same way and at the same rate to the rabbits in the Saline infusion group. The lumbar segments of 4-6 spinal cords were harvested and the IL-6 were examined 0 hour or 2 hours after reperfusion. The spinal cords of the rabbits in the control group were harvested right after anesthesia. Forty eight hours after reperfusion, the neurological functioning of the rabbits was assessed with the Tarlov scale system and the normal motor neurons of anterior horn of the lumbar segments of 4-6 spinal cords were counted.

RESULTS: The IL-6 levels of the rabbits in the Saline infusion group were significant higher than those in the control group and the Propofol infusion group (P < 0.05). There was no significant difference in the IL-6 level between the Propofol infusion group and the control group (P > 0.05). A significant increase of IL-6 in the rabbits in the Saline infusion group and the Propofol infusion group 2 hours after reperfusion was observed (P < 0.05). The rabbits in the Propofol infusion group had less paraplegia (30%) and more normal neurons (8.4) than those in the Saline infusion group (80% and 1.9, respectively) (P < 0.05).

CONCLUSION: Occlusion of aorta increases IL-6 in the injured spinal cords. Propofol aortic infusion can decrease the IL-6 level and improve the neurological functioning, which is perhaps associated with the inflammatory inhibition effect of Propofol.