缺血后适应对不同缺血时间家兔脊髓的保护作用

Effects of ischemic postconditioning against different times of spinal cord ischemia in rabbits

目的探讨缺血后适应对不同缺血时间家兔脊髓的保护作用。方法 40只家兔,随机分为4组(n=10):缺血20 min组(A组);缺血20 min+后适应组(B组);缺血30 min组(C组);缺血30 min+后适应组(D组)。脊髓缺血模型采用左肾动脉下腹主动脉阻断方法。A组:阻断20 min开放,无干预;B组:阻断20 min后开放1 min,然后间断阻断、开放4次,每次1 min;C组:阻断30 min开放,无干预;D组:阻断30 min,其余同B组。检测阻断前、开放后即刻1、h2、4 h血浆丙二醛(MDA)含量;14 d后取腰段脊髓进行组织学分析,应用免疫组织化学检测淀粉前体蛋白(APP)表达。结果 B组、D组MDA含量较A组、C组显著降低(P<0.01)。与A组比较,B组白质空泡区域明显减少(P<0.01),APP表达明显降低(P<0.01),正常运动神经元数目明显增加(P<0.05)。D组运动神经元受到一定保护,但与C组比较,差异无统计学意义(P>0.05)。结论缺血后适应对家兔脊髓30 min内缺血具有保护作用。

Objective To investigate the neuroprotective effects of ischemic postconditioning on spinal cords after transient ischemia of different time.Methods Forty rabbits were randomly divided into 4 groups（n=10 each）：group A,subjected to a 20 min ischemia without any intervention;group B,subjected to a 20 min ischemia followed by postconditioning comprised of four cycles of one minute occlusion/one-minute reperfusion at the start of reperfusion;group C,subjected to a 30 min ischemia;group D,subjected to a 30 min ischemia followed by postconditioning as group B.Plasma malondialdehude（MDA） was quantified before spinal cord ischemia,at the end of ischemia,1 h and 24 h after reperfusion.All rabbits were sacrificed 14 days after spinal cord ischemia to get the lumbar spinal cords for histological study.Immunohistochemical staining was used to assess the expression of amyloid precursor protein（APP）.Results Plasma MDA levels were markedly decreased in the group B and group D compared with the corresponding control groups（P〈0.01）.Much more large motor neurons were preserved in group B（P〈0.01）.Conclusion Postconditioning provides neuroprotection against spinal cord ischemia in rabbits if the ischemic time is less than 30 min.