迷走神经预调对心肌缺血再灌注损伤预防作用的实验研究

Experimental study of preventive effect of vagal nerve preconditioning on myocardial ischemia/reperfusion injury

目的：探讨心脏迷走神经预调对心肌缺血再灌注损伤的预防作用及其机制，以建立一种新的围手术期心肌保护方法。方法：实验用健康杂种犬１６ 只，随机均分为对照组（Ｃ 组） 和迷走神经预调组（Ｐ组） 。常规建立体外循环。分别于主动脉阻断前以３０Ｈｚ，０ ．５ｍｓ，１０Ｖ 方波刺激心脏迷走神经３ｍｉｎ ，间隔３ｍｉｎ ，重复２ 次。转流前、主动脉阻断前、复跳即刻、再灌注３０ｍｉｎ 、６０ｍｉｎ 时测心输出量（ＣＯ） 、射血分数（ＥＦ） 及左室（ＬＶ）ｄｐ／ｄｔ。并经冠状静脉窦抽血测乳酸（ＬＡ） 、乙酰胆碱（Ａｃｈ） 、Ｃａ＋ ＋ 、丙二醛（ＭＤＡ） 。结果：主动脉阻断前Ｐ组Ａｃｈ 和Ｃａ＋ ＋ 明显高于Ｃ 组，而再灌注期间低于Ｃ 组（ Ｐ＜ ０ ．０１） 、再灌注期Ｐ 组ＬＡ 和ＭＤＡ 明显减少（ Ｐ＜ ０ ．０１） 。术后ＣＯ、ＥＦ、ＬＶｄｐ／ｄｔ Ｐ 组高于Ｃ 组（ Ｐ＜ ０ ．０１） 。结论：迷走神经预调对心肌缺血和再灌注损伤有一定预防作用。

Aim:To evaluate the new method of perioperative myocardial protection against ischemia/perfusion injury by vagal nerve preconditioning.Methods:Sixteen healthy mongrel dogs were randomly divided into two groups,group C(n=8,control group) and group P(n=8,preconditioning group).CPB was carried out routinely.A preconditioning regimen consisted of two 3-minute cycles of cardiac vagal nerve stimulation with 30Hz,0.5ms,10V rectangular wave followed by 3-minute of interval in group P before aorta crossclamping.Cardiac output(CO) and ejection fraction (EF) were measured and blood samplies were taken from coronary sinus for the determination of lactate (LA),acetylcholine(Ach),Ca ++ and malondialdehyde(MDA) before CPB,before aortic crossclamping,after release of aortic crossclamping,and 30 minutes,60 minutes during reperfusion. Results:The level of Ach and Ca ++ of group P were significantly higher than those of group C before aortic crossclamping,and lower than those of group C during reperfusion(P< 0.01 ).The level of LA and MDA were reduced significantly during reperfusion (P<0.01).CO,EF and LV dp/dt of group P were higher than those of group C(P<0.01) after operation.Conclusion:The results suggest that vagal nerve preconditioning is effective in myocardial protection and against reperfusion injury.