脊髓麻醉对大鼠急性心肌缺血再灌注室性心律失常的影响研究

Study on the effect of spinal anesthesia on ventricular arrhythmias in acute myocardial ischemia-reperfusion in rats

目的:探索脊髓麻醉对急性缺血再灌注室性心律失常的影响及其机制。方法:通过结扎大鼠冠状动脉左前降支30 min后松开45 min建立急性心肌缺血再灌注模型(myocardial ischemiareperfusion, MIR),经脊髓鞘内途径缓慢注射布比卡因(1 mg/kg),记录脊髓麻醉前后的大鼠胸段T2脊髓电图变化,观察并记录室性心律失常的发生情况,超声检查大鼠心功能指标;HE和TTC染色检测心肌组织改变。结果:MIR引起左心室短轴缩短率(LVFS)和左心室射血分数(LVEF)减退和心肌组织学损伤,造成缺血期和再灌注期引发室性心律失常,电生理记录脊髓放电频率增加。脊髓注射布比卡因可显著抑制MIR诱发的心律失常;同时,布比卡因可显著改善MIR引起的脊髓神经放电活动、心肌组织学损伤和心脏功能抑制。结论:本研究表明脊髓麻醉能够消除MIR引起的室性心律失常,其机制可能与其抑制MIR心脏脊髓后角神经元电异常活动有关。

AIM:To explore the effect of spinal anesthesia on ventricular arrhythmia and involved mechanisms in myocardial ischemia-reperfusion(MIR)rats.METHODS:The rat MIR model was made by occlusion the left anterior descending coronary artery for 30 minutes and reperfusion for 45 minutes.Bupivacaine(0.05 mL/100 g,1 mg/kg)was injected slowly via intrathecal for spinal anesthesia.The electromyelogram at T2 thoracic spinal cord was recorded.Ventricular arrhythmias,cardiac function,myocardial damage were assessed by electrocardiography,echocardiography and TTC or HE staining.RESULTS:MIR reduced left ventricular short-axis shortening(LVFS)and left ventricular ejection fraction(LVEF),caused myocardial histological damage and ventricular arrhythmias,promoted spinal electrical discharge frequency and amplitude in T2 dorsal horn.Spinal injection of bupivacaine could significantly reduce spinal cord electrical activities and eliminate MIR-induced arrhythmias.Moreover,bupivacaine also significantly improved MIR-induced myocardial histological damage and cardiac function inhibition.CONCLUSION:Spinal anesthesia can reduce ventricular arrhythmias induced by MIR.The mechanism may be related to the effect of abolishing spinal nerve excitability.