葡萄糖-胰岛素-钾液对缺血/再灌注心肌的保护作用

Protective effects of glucose-insulin-potassium on ischemic-reperfused canine heart

目的:观察极化液(葡萄糖-胰岛素-钾液,G IK)对急性心肌缺血/再灌注(M I/R)犬心脏功能、冠脉血流量及心肌损伤的影响,分析胰岛素在G IK上述效应中的作用。方法:制备犬M I/R模型,心肌定量缺血(左前降支血流量降低80%)50 m in,再灌注4 h。24只杂种犬随机分为G IK、葡萄糖-钾液(GK)和盐水对照组(n=8/组),再灌注前5m in输注G IK、GK、生理盐水。观察冠脉血流量及血流动力学指标;检测不同时间血清乳酸脱氢酶(LDH)、肌酸激酶(CK)活性;再灌注4 h后测量并计算心肌梗死范围。结果:与盐水对照组相比,G IK明显增加左前降支冠脉血流量(CBFLAD),改善再灌注后左室收缩及舒张功能,降低血清CK、LDH,减少心肌梗死范围,而GK无上述作用。结论:再灌注时输注G IK可促进再灌注心脏功能恢复及减轻心肌损伤,该作用可能与G IK增加冠脉血流量有关;胰岛素是G IK上述作用的关键成分。

AIM： To study the effects of glucose-insulin-potassium （GIK） on coronary blood flow （CBF） , cardiac functional recovery and myocardial injury following acute myocardial ischemia/reperfusion （MI/R） , and analyze the role of insulin in the cardioprotective effects of GIK. METHODS： In anesthetized open-chest dogs, the left anterior descending coronary artery （ LAD） was partially occluded （80% reduction in its blood flow） for 50 min and reperfused for 4 h. Dogs were randomly divided into three groups： GIK, GK and Saline. All treatments were given beginning at 5 min before the reperfusion （ infused at 2 ml·kg^-1· h^-1 , i.v. ） and continuing during the 4h reperfusion. Arterial blood pressure, ECG, CBF and left ventricular pressure were monitored. The activities of CK and LDH were assayed spectrophotometrically. Myocardial infarction was determined by Evans blue-TTC double staining at the end of the reperfusion. RESULTS： During the reperfusion, compared with the saline group, GIK increased the CBFLAD of the dogs treated at the end of the reperfusion, P 〈 0.05, improved recovery of LVSP and ＋ LVdp/dtmax. In addition, GIK-treated dogs showed protection against MI/R as evidenced by significant decreases in serum CK and LDH, and reduced myocardial infarction, while GK failed to show any significant cardioprotection against MI/R injury. CONCLUSION： GIK exerts cardioprotective effects by improving cardiac functional recover,） and reducing myocardial injury during reperfusion, which may be partly attributable to the increased coronary blood flow elicited by GIK infusion. Insulin plays a leading role in the aforementioned actions of GIK.