[Protective effect of hypothermic propofol on ischemic spinal cords]

To evaluate the protective effect of hypothermic propofol infused via the aorta against ischemia/reperfusion injury of spinal cords in rabbits.

Sixty New Zealand white rabbits were randomly divided into six groups (n=10 in each group). The infrarenal circum-aortic clamping model was used in this study. During the 30-clamping time, 5 mL/kg of normal saline, 10% intralipid, propofol, 4 degrees C saline, 4 degrees C intralipid and 4 degrees C propofol were infused into the left femoral arteries of the rabbits in group SN, IPN, PN, SH, PH and IPH, respectively, at a rate 10 mL/(kg x h). The heart rates, blood pressures, respiratory rates and SPO2 were measured during the ischemic-reperfusion processes. The neurological status (Tarlov Scale system) were assessed 6 h, 24 h, and 48 h after the reperfusions. The spinal cords were harvested 48 h after the reperfusions for histological analysis. The concentrations of excitatory amino (EAA, aspartate and glutamate), malondialdehyde (MDA) and superoxide dismutas (SOD) in the harvested spinal cords were determined.

Group PN, SH, PH and IPH had better neurological outcomes and less severe pathological changes than group SN and IPN (P<0.05). There were no significant differences between group SN and IPN (P>0.05). Group PN, SH, PH and IPH had lower concentrations of EAA in spinal cords than group SN and IPN (P<0.05). Group PH had the best neurological outcome, the least histopathological changes of spinal cords, and the lowest concentrations of EAA (P<0.05). Groups PN and PH had lower concentrations of malondialdehyde than group SN, IPN, SH and IPH. Groups PN and PH had higher concentrations of superoxide dismutas than group SN, IPN, SH and IPH (P<0.05).

Both propofol and hypothermic liquids can protect spinal cords against ischemia/reperfusion injuries. Combined use of propofol and hypothermia results in significant recovery of spinal cord functions.