硬膜外注射吗啡对兔急性缺血再灌注后左心功能的影响

Effects of Epidural Injection of Morphine on Heart Function after Myocardial Infarction and Reperfusion in Rabbits

目的在兔急性心梗再灌注模型中通过硬膜外给予吗啡,探讨其对兔心肌急性缺血再灌注损伤的保护作用。方法采取开胸结扎LAD(left anterior descending,左前降支)的急性心肌梗死模型,结扎冠状动脉LAD 30min后,松开结扎线,再灌注4 h。新西兰兔22只随机分成2组:①硬膜外吗啡组:经硬膜外注入吗啡(0.25 mg/kg,配成0.5 mL溶液);②对照组:经硬膜外注入生理盐水0.5 mL。缺血再灌注后逐层关胸,4周后行超声心动图检查。结果缺血再灌注后4周,两组LVEDD和LVESD均明显增大,但以对照组为甚,组间比较差异有显著性(P<0.05);而LVEF和LVFS,在缺血再灌注后4周硬膜外吗啡组分别降低了9.36%和8.24%,对照组分别降低了13.53%和12.18%,对照组比硬膜外组更显著(P<0.05),左室心功能硬膜外吗啡组好于对照组(LVEF:69.73%vs.62.99%;LVFS:31.39%vs.26.59%;LVEDD:14.35 vs.16.96;LVESD:9.52 vs.12.01),差异有统计学意义(P<0.05)。结论硬膜外注射吗啡能改善缺血再灌注后左心功能,并对缺血再灌注心肌有明显的保护作用。

Objective The study was designed to investigate the protective effects of epidural injection of morphine in the rabbit model of acute myocardial ischemia and reperfusion injury in respects of heart function. Method The rabbit opening thorax and LAD ligation model was created to present acute myocardial ischemia and reperfusion. Twenty-two rabbits were divided randomly into two groups： epidural morphine group and control group. Either morphine （0.25 mg/kg, 0.5 mL） or normal saline 0.5 mL was injected epidurally in corresponding group over a period of 2 min - 20 min before coronary artery occlusion. The left anterior descending （LAD） coronary artery was occluded for 30 min, and then reperfusion was performed. After reperfusion, the thoracic cavity of the rabbits was closed up and the rabbits were surviving. Echocardiographic assessment was undertaken 4 weeks after myocardial infarction and reperfusion. Results The LVESD and LVEDD in the two groups increased significantly, but more pronounced in the control group（ P 〈 0.05）. Meanwhile, the LEVF and LVFS in two groups decreased significantly （9.36% and 8.24% in the epidural morphine group, 13.53% and 12.18% in the control group, respectively）, but more pronounced in the control group（ P 〈 0.05）. The heart function of left ventricle of the epidural morphine group was better than that of the control group （LVEF： 69.73% vs. 62.99%; LVFS： 31.39% vs. 26.59% ;LVEDD： 14.35% vs. 16.96; LVESD： 9.52 vs. 12.01）, the difference was statistically significant （ P 〈 0.05）. Conclusion Epidural injection of morphine can improve the heart function after myocardial infarction and reperfusion, and can effectively protect the myocardium from the injury of infarction and reperfusion.