七氟烷后处理对氧自由基介导减轻兔脊髓缺血再灌注损伤的作用

目的 观察七氟烷后处理足否可以减轻兔脊髓缺血再灌注损伤以及氧自由基在其中的作用.方法 (1)雄性新西兰大白兔48只,随机分为6组(n=8):假手术组,仅行单纯手术操作但不阻闭腹主动脉;对照组,行单纯缺血再灌注,即阻闭腹主动脉20 min后进行再灌注;纯氧后处理组,在再灌注前5 min给予100%O2,持续13 min.七氟烷后处理组(Sevo0.5组/Sevo1.0组/Sevo1.5组),分别冉灌注前5 min给予0.5、1.0及1.5 MAC(肺泡气最低有效浓度)七氟烷处理,持续10 min,然后100%O2洗脱3 min.(2)雄性新西兰大白兔36只,随机分为4组(n=9).纯氧组及七氟烷组,分别接受纯氧和1.0MAC七氟烷后处理并于后处理前1h静脉注射生理盐水5 ml/kg,DMTU+七氟烷及DMTU+纯氧组,分别接受纯氧和1.OMAC七氟烷后处理并于后处理前1 h静脉注射10%二甲基硫脲(DMTU)5 ml/kg.再灌注48 h对所有动物的后肢运动功能进行评分并取脊髓行HE染色对行脊髓前角正常神经元计数.结果 (1)再灌注48 h,七氟烷后处理组后肢运动功能评分和脊髓前角正常神经元计数均显著高于对照组(P＜0.05),脊髓前角正常神经元计数Sevo1.0组明显多于Sevo0.5组和Sevo1.5组(P＜0.05).(2)再灌注48 h,七氟烷组、DMTU+七氟烷及DMTU+纯氧组的后肢运动功能评分和脊髓前角正常神经元计数均明显高于纯氧组(P＜0.05);脊髓前角正常神经元计数七氟烷组明显高于DMTU+七氟烷及DMTU+纯氧组(P＜0.05).结论 七氟烷后处理通过氧自由基介导减轻兔脊髓缺血再灌注损伤.

Effect of sevoflurane postconditioning on spinal cord ischemia reperfusion injury via the release of oxygen free radicals in rabbits

Objective To investigate whether posteonditoning with sevoflurane could alleviate spinal cord ischemia reperfusion injury in rabbits,and whether the beneficial effect is dependent on oxygen free radicals.Methods In Experiment 1.48 male New Zealand white rabbits were randomly assigned to six groups(n=8 each).Animals in the sham group only underwent sham-operation.Animals in the control group underwent spinal cord ischemia for 20 min without postconditioning.Animals in O2 postconditioning group(Group O2)inhaled 100%O2 from 5 min before reperfusion and lasted 13 min. Animals in sevoflurane postconditioning groups(Group Sevo0.5,Sevo1.0 and Sevo1.5)inhaled 0.5,1.0,1.5minimum alveolar concentration(MAC)sevoffurane in 100%O2,from 5 min before reperfusion and lasted 10min,then inhaled 100% O2 for 3 min to wash out the remaining sevoflurane.In Experiment 2.36 male New Zealand White rabbits were randomly assigned to four groups(n=9 each).Animals in O2 and Sevo groups received normal saline(5 ml/kg intravenously)1 h before postconditioning with 100% O2 and 1.0 MAC sevoflurane,respectively.In the DMTU+Sevo and DMTU+O2 groups,5 mL/kg of 10%dimethylthiourea (DMTU,a potent oxygen free radical scavenger.dissolved in saline)was administered intravenously at the same time.Spinal cord ischemia was induced by an infrarenaI aorta clamping for 20 min.Forty-eight hours after reperfusion,hind-1imb motor funetion and histopathology of the spinal cord were examined in a blinded fashion.Results (1)The neurologic and histopathologic outcomes in the sevoflurane postconditioning groups were better than those in the control group(P＜0.05),the histopathologic outcomes in Sevo1.0 group were better than that in Sevo0.5 and Sevo1.5 groups(P＜0.05).(2)The neurologic and histopathologic outcomes in Sevo.DMTU+Sevo and DMTU+O2,groups were better than those in the O2 group(P＜0.05).the histopathologic outcomes in Sevo group were better than that in the DMTU+Sevo and DMTU+O2 groups(P＜0.05).Conclusions Our study demonstrates that sevoflurane postconditioning against spinal cord ischemia injury via the release of oxygen free radicals in rabbits.