The Protective Effect Of Hypothermic Propofol Infusion Via The Aorta On Ischemic Spinal Cord In Rabbits

Objective: To evaluate the protective effect of hypothermic propofol infused via the aorta against ischemia/reperfusion injury of spinal cord in rabbits.Methods: 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, normal saline, 10％intralipid, propofol, 4℃saline, 4℃intralipid and 4℃propofol were infused into the left femoral artery respectively in groups A, B, C, D, E and F. In each group, the volume of the infusing liquids were equally 5ml/kg. Heart rate, blood pressure, respiratory rate and SPo2 were measured during the ischemic-reperfusion process. And the neurological status (Tarlov Scale system) were assessed at 6h, 24h, 48h after the reperfusion. The spinal cord were sampled at 48h after the reperfusion for histological analysis. In addition, the concentrations of excitatory amino (EAA, aspartate and glutamate), malondialdehyde (MDA) and superoxide dismutas (SOD) in spinal cord were measured. Statistical analyses were performed with PEMS 3.1 software package and SPSS 12.0 software. P＜0.05 were considered statistically significant.Results: The neurological outcomes were better and the pathological changes were less severe in groups C, D, E and F than in groups A and B (p＜0.05). There were no significant difference between group A and B (p＞0.05). In groups C, D,E and F, concentrations of EAA in spinal cord were significantly lower than those in group A and B (p＜0.05). The neurological outcome of group E was the best one in groups A to F, the histopathological changes of spinal cord was the least, and the concentration of EAA was the lowest (p＜0.05). The concentration of malondialdehyde was lower in groups C and E than in groups A, B, D and F. While the concentrations of superoxide dismutas were higher in groups C and E than those of groups A, B, D and F (p＜0.05).Conclusions: Propofol and hypothermic liquids both can protect the spinal cord against ischemia/reperfusion injury Combined use of propofol and hypothermia resulted in highly significant recovery of spinal cord function.