一氧化氮对犬心肌顿抑心功能的影响

Effect of nitric oxide on cardiac function in canine myocardial stunning

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摘要目的　探讨心肌顿抑 (myocardialstunning,MS)时局部组织一氧化氮 (NO)含量的变化 ,及补充或抑制NO对顿抑心肌功能的影响。方法　将 35条犬随机分为 5组 (每组 7条 ) ,即MS组、亚硝基左旋精氨酸甲酯 (NG nitro L argininemethylester,L NAME)组、左旋精氨酸 (L Arginine,L Arg)组、3 morpholinosydnonimine (Sin 1,一种NO供体 )再灌注组及对照组。实验组均通过开胸阻断左冠状动脉前降支 (LAD) 15min再灌注 3h建立MS模型 ,采用微电极法和Greiss法检测心肌表面及冠状窦血中NO含量变化 ,根据血流动力学监测及经食管彩色多普勒血流仪 (transesophagealechocardiography ,TEE)观察心功能及缺血节段室壁运动的变化。结果　 (1)阻断犬LAD 15min后 ,所有犬均发生MS ,主要表现为前壁室壁运动减弱 ,左室±dp/dt减低 ;(2 )缺血再灌注期 ,顿抑心肌合成NO减少 ,L Arg及Sin 1可明显增加顿抑组织的NO含量 ,而L NAME则降低NO含量 ;(3)再灌注L Arg及Sin 1在早期即可明显减轻顿抑心肌的室壁运动障碍 ,使心功能相对改善。结论　心肌顿抑时局部顿抑组织NO含量减低 ,再灌注早期补充NO供体Sin 1及前体L Arg可明显改善顿抑心肌的缩舒功能 ,而用L NAME阻断NO的合成后则无此作用。 Objective To investigate the change of Nitric Oxide (NO) content in the local stunned myocardium, and the effect of supplying and suppressing NO on the functions of the stunned myocardium. Methods Thirty five dogs were randomly divided into 5 groups (7 in each), namely groups of stunned, reperfusion of NG nitro L arginine methyl ester (L NAME), L Arginine(L Arg), 3 morpholino sydnonimine (Sin 1) and control. The model of myocardial stunning (MS) was established by occluding the branch of left anterior descending (LAD) for 15 min followed by 3 h of reperfusion. NO in local myocardium and coronary sinus were detected by micro electric probe and Greiss's method. Changes of ventricular wall motion and cardiac function were measured by transesophageal echocardiography(TEE) and hemodynamic monitoring. Results (1) The stunned state developed in all dogs after 15 min of ischemia, in forms of decreased ventricular wall motion and ±dp/dt. (2) Local NO content reduced during ischemia reperfusion (I/R), could be increased by L Arg and Sin 1 and lowered by L NAME. (3) Early reperfusion of L Arg and Sin 1 markedly reduced the disturbance of ventricular wall motion and improved cardiac function. Conclusion Local NO declined when myocardium was stunned, early reperfusion of NO precursor(L Arg) and donor (Sin 1) could improve the cardiac function of the stunned myocardium, while L NAME did not have such effect.