心肌缺血再灌注损伤中核因子-κB活性的变化

The changes of nuclear factor-κB(NF-κB) in myocardial ischemic/reperfusion injury

目的观察心肌缺血再灌注时心肌细胞核因子-κB(NF-κB)活性的变化以及甲基强的松龙对心肌缺血再灌注损伤的影响。方法健康家犬12只,随机分为甲基强的松龙组(M组,n=6)和对照组(C组,n=6),两组动物均在全麻和机械通气下开胸建立心肺转流(CPB),冠脉灌注冷晶体停搏液使心电静止,主动脉阻断120 min后开放进行心脏复苏,循环稳定后停止CPB,继续观察至开放90 min;M组在麻醉后经静脉给予甲基强的松龙5 mg/kg,其余同对照组。CPB前(T0)、主动脉开放前(T1)、开放后30 min(T2)、90 min(T3)各时间点分别采取动脉血和右室前壁心肌组织,用125I标记的放免试剂盒测定细胞因子(TNF-α、IL-1βI、L-6I、L-8)的含量,用Western blot测定心肌组织NF-κB P65的活性及其病理学改变。结果两组动物T1、T2、T3各时点TNF-αI、L-1βI、L-6I、L-8水平和NF-κB活性均较T0显著升高(P<0.01),并且T1、T2、T3各时点M组较C组显著降低(P<0.01)。病理显示两组在T1、T2、T3各时点心肌组织中性粒细胞浸润增加,且T2、T3较T1时更明显;T1、T2、T3各时点M组较C组显著减轻。结论CPB可引起心肌细胞的NF-κB活化和细胞因子显著增加,产生心肌损伤,甲基强的松龙可抑制NF-κB的活性和减少细胞因子的释放,减轻心肌缺血再灌注损伤。

Objective To study the changes of nuclear factor-kappa B（NF-κB） and cytokines in myocardial Ischemic/Reperfusion injury during cardiopulmonary bypass（CPB）. Methods Twelve healthy male dogs（21-28 kg） were randomized divided into Methylprednisolone group（group M, n=6） and control group（group C, n=6）. CPB was performed with cardiac arrest by cardioplegic solution during aorto-block. Cardiac resuscitation was made after 120 rain of aorto-block and weaned from CPB when circulation lasting. Blood-serum cytokines（TNF-α, IL-1β, IL-6, IL-8）, NF-κB P65 and pathology change of myocardium tissue were measured before CPB（T0）,before release of aorto（T1）,30 min（T2） and 90 min（T3） after release of aorto. Results The activation of NF-κB,levels of all cytokins increased significantly at T1 ,T2 ,T3 than that of at To in two groups （P〈0.01）. The activation of NF-κB, levels of all cytokins decreased significantly in M group than that of C group at T1 ,T2 ,T3 （P〈0.01）. Tissue section display that neutrophil accumulated in myocardium tissue increased at T1, T2, T3 in two groups and M group was slighter than C group. Conclusion Myocardial Ischemic/Reperfusion injury was involved with the activation of NF-κB which increased the level of the cytokines. Methylprednisolone strongly attenuates the activation of NF-κB and the level of the inflammatory cytokines, protect the heart from Ischernic/Reper{usion injury during CPB.