无创肢体缺血预处理对兔缺血性心肌的影响

Influence of Non-invasive Limb Ischemia Preconditioning on Ischemic Myocardial Injury in Rabbits

目的:通过观察不同组兔心肌中热休克蛋白(HSP70),环氧合酶(COX-2),一氧化氮合酶(iNOS),肿瘤坏死因子-α(TNF-α),转录因子-κB(NF-κB)mRNA的表达以及超氧化物歧化酶(SOD),丙二醛(MDA)和一氧化氮(NO)的变化,探讨无创肢体缺血预处理对兔缺血性心肌的影响和可能机制。方法:实验分单纯缺血对照(Ctr),无创肢体缺血预处理(LIP)和LIP+K ATP抑制剂(LG)组。Ctr组不作特殊处理,先静脉注射垂体后叶素后,再静脉注射肾上腺素诱发心律失常;LIP组兔双后肢缺血5 min,再灌注5 min,重复4次建立无创肢体缺血预处理模型,余同Ctr组;LG组先静脉注射K ATP抑制剂(格列本脲),余处理同LIP组;实验结束后取心肌组织标本,生化法检测心肌组织中SOD活力,MDA,NO含量;RT-PCR法检测心肌组织中HSP70,COX-2,iNOS,TNF-α及NF-κB mRNA的表达。结果:与Ctr组相比,LIP组COX-2和iNOS表达增高,TNF-α与NF-κB表达明显降低,LG组HSP70表达明显降低;与LIP组相比,LG组HSP70和iNOS表达均明显降低,TNF-α和NF-κB表达明显增高。心肌组织中SOD活力LIP组较高,LG组与Ctr和LIP组无差异;MDA含量Ctr组高于LIP组和LG组;NO含量LIP组较高,LG组NO含量与Ctr组相比无差异。结论:LIP具有减轻缺血性心肌损伤的作用,K ATP是其发挥保护作用的重要途径。

Objective： To discuss effects and the possible mechanism of noninvasive limb ischemic preconditioning on ischemic myocardial rabbits by observing the expression of heat shock protein 70（HSP 70）,cyclooxygen ase-2（COX-2）,inducible nitric oxide synthase（iNOS）,tumour necrosts factor-α（TNF-α）,nudear factor-κB（NF-κB） mRNA and the variation of superaxide（SOD）,malondialdehyde（MDA） and nitric oxide（NO）.Method： Rabbits were randomly divided into ischemia control（Ctr） group,non-invasive limb ischemic preconditioning（LIP） group,LIP ＋ K ATP antagonist,glibenclamide,（LG） group.In ctr group any special treatment was not performed,but the vasopressin was injected intravenously to produce myocardial ischemia background,then epine-phrine was injected to induce arrhythmia。 Double hindlimb ischemia 5 min and reperfusion 5 min was carried out with repetitionof four times to set up a non-invasive limb ischemic preconditioning model.Another methods and contents of observation were same as the Ctr group.The K ATP antagonist（glibenclamide） was injected intravenously to LG group rabbits beforehand,another treatments same with the LIP group.After that,SOD,MDA,NO levels in myocardial tissue were detected by biochemistry method;The mRNA expression level of HSP 70,COX-2,iNOS,TNF-α and NF-κB was evaluated by RT-PCR.Result： In LIP group COX-2 and iNOS expression level was significantly higher compared with the Ctr group,and TNF-α and NF-κB expression level was significantly reduced;in LG group HSP 70 and iNOS expression level was significantly reduced compared with the LIP group,and the TNF-α and NF-κB expression level was significantly increased,and the difference was statistically significant.SOD level in myocardial tissuein LIP group was higher than others,there was no significant difference between Ctr and LIP group;MDA level in Ctr group wasa higher than other groups;NO level in LIP groupwas higher than others,therewas no significant difference between Ctr and LG group.Conclusion： LIP can effectively improve the ischemic myocardial injury,and the K ATP pathway may have a very important role in its protective effects.