低温异丙酚对脊髓缺血再灌注损伤保护作用的实验研究

Protective Effect of Hypothermic Propofol on Ischemic Spinal Cords

目的探讨低温异丙酚经腹主动脉灌注对兔脊髓缺血再灌注损伤的保护作用。方法健康成年新西兰大白兔60只。随机分为6组,每组10只,分别为SN组(生理盐水组)、IPN组(10%常温脂肪乳组)、PN组(50mg/kg常温异丙酚组)、SH组(4℃生理盐水组)、PH组(4℃50mg/kg异丙酚组)、IPH组(4℃10%脂肪乳组)。每组的灌注容积均为5mL/kg,灌注速度为10mL/(kg.h)。采用左肾下腹主动脉阻断法建立脊髓缺血再灌注模型,阻断开始时即泵入灌注液,30min后停止灌注并开放腹主动脉。记录术中兔生命体征及再灌注后6h、24h、48h神经行为学评分,于再灌注后48h取L4-6节段脊髓观察组织形态学改变;取T8节段脊髓组织作为正常对照(N组),测定L4-6脊髓组织中兴奋性氨基酸(EAA)及丙二醛(MDA)、超氧化物歧化酶(SOD)的含量。结果①与对照组(SN、IPN组)比较,常温异丙酚组(PN组)和低温灌注组(SH、PH、IPH组)动物神经行为学评分均明显升高,脊髓组织中EAA含量明显降低,其中以低温异丙酚组(PH组)最显著(P<0.05),SN、IPN组间差异无统计学意义。②与正常对照组(N组)比较,各实验组(SN～IPH组)L4-6脊髓组织中EAA及MDA含量明显升高,而SOD含量明显降低(P<0.05)。③与SN、IPN、SH、IPH组比较,常温和低温异丙酚组(PN、PH组)脊髓组织中SOD含量明显升高,MDA含量降低(P<0.05)。但PN、PH两组间差异无统计学意义。结论异丙酚及低温液体均能减轻脊髓缺血再灌注损伤,具有脊髓保护作用,其中低温异丙酚的保护作用更显著。

Objective To evaluate the protective effect of hypothermic propofol infused via the aorta against ischemia/reperfusion injury of spinal cords 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, 5 mL/kg of normal saline, 10% intralipid, propofol, 4 ℃ saline, 4 ℃ intralipid and 4 ℃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 · h）. The heart rates, blood pressures, respiratory rates and SPO2 were measured during the ischemie-reperfusion processes. The neurological status （Tarlov Scale system） were assessed 6h, 24 h, and 48 h after the reperfusions. The spinal cords were harvested 48h 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. Results Group PN, SH, PH and IPn 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）. Conclusion 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.