"渐处理"降低了犬心肌缺血/再灌注损伤

目的 扩大缺血后处理在临床上的应用,验证“渐处理”,即一种改良的后处理方式是否对再灌注心肌有保护作用.方法 建立犬心肌缺血/再灌注（I/R）模型,缺血40 min后分别给予以下处理：（1）再灌注3 h;（2）后处理,缺血30 s,再灌注30 s,进行3个循环后放开冠状动脉进行再灌注3 h;（3）渐处理,逐步恢复冠状动脉血流,50%2 min,80%2 min,之后再灌注3 h.全程监测心电图和心功能指标,检测血清中心肌酶活性,再灌注结束后对心脏进行伊文思蓝-红四氮唑（TTC）染色判断心肌坏死率.结果 上述各项指标显示后处理和渐处理均降低了I/R损伤,减少了再灌注诱发的心律失常.结论 作为一种改良的后处理方式,渐处理对再灌注心肌的保护作用显著.

Equivalent cardioprotective effect of "half-conditioning" and post-conditioning in a canine model of myocardial ischemia and reperfusion

Objective To study the effects of "half-conditioning", a modified postconditioning process, on myocardial injury induced by severe myocardial ischemia/reperfusion (I/R) in anesthetized dogs.Methods Mongrel dogs of both sexes were subjected to 40 min ischemia (coronary blood flow reduced by 80% via controlled coronary stenosis). At the end of ischemia, dogs were randomly received one of the following treatments: (1) control, reperfusion for 3 h (n=7); (2) post-conditioning, three cycles of ischemia 30 s followed by reperfusion for 30 s and then reperfusion for 3 h (n=7); (3) half-conditioning, coronary blood flow recovered to 50% for 2 min, then 80% for 2 min, thereafter 100% for 3 h (n=7). Electrocardiogram (ECG), arterial blood pressure and left ventricular pressure were monitored throughout the experiment. Plasma creatine kinase (CK) and lactate dehydrogenase (LDH) activity were measured spectrophotometrically. Myocardial necrosis was defined by TTC-staining. Results Compared with control animals, arrhythmia incidence, LVEDP at 2 and 3 h reperfusion, CK and LDH were significantly reduced in animals received post-conditioning and half-conditioning treatments, infarct size as a percentage (%) of the area at risk was also significantly reduced by post-conditioning and half-conditioning treatments. No differences were observed in the post-conditioning and half-conditioning groups. Conclusion Half-conditioning exerts the same cardioprotective effects on post-ischemic hearts as postconditioning.