摘要
目的 探讨活性氧自由基（ROS）和磷酸酰肌醇3激酶-蛋白激酶B（PI3K-Akt）在缺血后处理或控制性低压灌注减轻大鼠脊髓缺血再灌注损伤中的作用.方法 雄性SD大鼠126只,体重300～350 g,随机分为7组（n=18）,缺血再灌注组（I/R组）阻断胸主动脉同时维持MAP40 mm Hg持续9 min进行脊髓缺血,胸主动脉开放后使MAP升至100 mm Hg进行脊髓再灌注;缺血后处理组（IP组）开放主动脉后,进行再灌注30 s缺血30 s,重复3次,同时维持MAP 100 mm Hg;控制性低压灌注组（LR）开放主动脉后维持MAP 40 mm Hg持续5 min后升高至100 mm Hg;缺血后处理＋PI3K抑制剂LY-294002组（IP＋L组）和控制性低压灌注＋LY-294002组（LR＋L组）分别于实施缺血后处理和控制性低压后立即动脉注射LY-294002 25 mg/kg;缺血后处理＋氧自由基清除剂N-乙酰半胱氨酸组（IP＋N组）和控制性低压灌注＋N-乙酰半胱氨组（LR＋N组）分别于实施缺血后处理和控制性低血压后立即动脉注射N-乙酰半胱氨酸100 mg/kg.于再灌注2 h时,各组处死12只大鼠,取腰段脊髓组织,测定胞浆Akt磷酸化水平和线粒体通透性转换孔（mPTP）开放程度.分别于再灌注4、12、24、48 h进行神经行为学评分,然后处死大鼠,取腰段脊髓组织,分别进行脊髓前角正常神经元和凋亡神经元的计数.结果 与I/R组比较,IP组和LR组Akt磷酸化水平升高,mPTP开放程度和神经元凋亡计数降低,神经行为学评分和正常神经元计数升高（P＜0.01）;IP组与LR组各指标比较差异无统计学意义（P＞0.05）.LY294002和N-乙酰半胱氨酸均可逆转缺血后处理和控制性低压灌注对脊髓的保护作用,引起mPTP开放程度升高（P＜0.01）.结论 ROS激活PI3K-Akt进而降低线粒体通透性是缺血后处理或控制性低压灌注减轻大鼠脊髓缺血再灌注损伤的机制.
Objective To investigate the roles of reactive oxygen species （ROS） and phosphatidyl-inositol 3-kinase-Akt （PI3K-Akt） in neuroprotection against spinal cord ischemia-reperfusion （I/R） injury by ischemic postconditioning （IP） or controlled low perfusion pressure （LR）. Methods One hundred and twenty-six adult male SD rats weighing 300-350 g were randomly divided into 7 groups （n = 18 each）： group Ⅰ I/R; group ⅡIP; group Ⅲ LR; group Ⅳ IP ＋ LY-294002 （IP ＋ LY）; group Ⅴ LR ＋ LY-294002 （LR ＋ LY）; group Ⅵ IP ＋N-acetylcysteine （IP＋ N） and group Ⅶ LR＋ N-acetyl-cysteine （LR＋ N）. Spinal cord ischemia was induced by 9 min occlusion of the thoracic aorta combined with controlled hypotension （MAP = 40 mm Hg）. In IP group the animals were subjected to 3 cycles of 30 s reperfusion interspersed with 30 s ischemia immediately after release of aortic occlusion. In LR group MAP was maintained at 40 mm Hg for another 5 min immediately after release of aortic occlusion, then increased to 100 mm Hg. In group Ⅳ-Ⅶ LY-294002 （PI3K inhibitor） 25 mg/kg or N-acetylcysteine （ROS scavenger） 100 mg/kg were administered at the onset of reperfusion. Twelve animals in each group were killed at 2 h of reperfusion. The lumbar segment of the spinal cord was removed for determination of the level of Akt phosphorylation and opening of mitochondrial permeability transition pore （mPTP）. Neurological function was assessed and scored （15 = normal function, 0 = unable to move hind limb） at 4, 12, 24 and 48 h of reperfusion in another 6 animals in each group. The animals were then killed after last assessment and the lumbar segment of the spinal cord was removed for detection of apoptotic neurons. Results Compared with I/R group,both IP and LR significantly enhanced the level of Akt phosphorylation in the spinal cord, inhibited mPTP opening and neuronal apoptosis and increased neurological function scores. There was no significant difference in the protective effe
出处
《中华麻醉学杂志》
CAS
CSCD
北大核心
2010年第6期728-732,共5页
Chinese Journal of Anesthesiology
基金
南京军区医学科技创新课题（08MM12）
关键词
活性氧
1-磷脂酰肌醇3-激酶
蛋白激酶类
灌注
再灌注损伤
脊髓
缺血后处理
Reactive oxygen species
1-Phosphatidylinositol 3-kinase
Protein kinases
Perfusion
Reperfusion injury
Spinal cord
Ischemic postconditioning
