[摘要]目的 探讨单磷酰脂A(monophosphoryl lipid A，MLA)预处理24h对老年大鼠心肌缺血.再灌注损伤的影响及核转录因子.κB(NF.κB)在其中的作用。 方法 建立老年大鼠心肌缺血.再灌注损伤模型。36只大鼠随机分为3组，分别行单纯缺血.再灌注及应用MLA、NF.κB的特异性抑制剂DDTC加MLA预处理心脏24h后，对心脏进行较长时间缺血.再灌注，检测心肌梗死范围、乳酸脱氢酶(LDH)释放及心肌细胞凋亡率。另外30只大鼠随机分为5组，检测MLA预处理0、15、30、60min及DDTC加MLA预处理后30min时NF.κB活性。 结果 MLA预处理可减小心肌梗死范围(P<0.05)，降低血浆LDH活性(P<0.05)，减少心肌细胞凋亡率(P<0.01)。预处理使NF.κB呈时间依赖性激活，预处理前NF.κB活性低，预处理15min开始升高、30min达到高峰、60min开始下降。而应用NF.κB抑制剂DDTC可完全阻断NF.κB复合物活性的增加，也完全消除预处理的保护作用。 结论 MLA预处理24h对老年大鼠心肌再次缺血.再灌注损伤有保护作用。NF.κB参与老年大鼠心肌预处理后的延迟保护作用，MLA预处理后NF.κB快速的核转移并激活可能是药物预处理延迟保护作用的重要机制之一。

    [关键词] 核转录因子.κB;单磷酰脂A;缺血.再灌注损伤;凋亡;心肌保护;大鼠

    Role of NF.κB in the late phase of monophosphoryl lipid A preconditioning on ischemia.reperfusion injury in old rats heart

    CHENG Fang-zhou，MA Ye-xin，YU Xi-qiu，BAO Cui-yu，WU Ji.liang

    (Department of Cardiology，Affiliated Tongji Hospital，Tongji Medical College，Huazhong University of Science&Technonogy，Wuhan430030，China)

    Abstract:Objective To investigate the role of nuclear factor-κB(NF.κB)in the late phase of cardioprotec-tive effects induced by monophosphoryl lipid A(MLA)preconditioning on ischemia.reperfusion(I.R)injury in old rats heart.Methods Ischemic.reperfusion model of old rats was established.Thirty-six rats were randomly as-signed to three groups.Before ischemia.reperfusion rats of two graps were preconditioned by injection of MLA or DDTC+MLA for24hours.At the end of reperfusion ......