正中神经刺激对心肌梗死犬室性心律失常的影响

Effect of Median Nerve Stimulation on Ventricular Arrhythmia in a Canine Model With Experimental Myocardial Infarction

目的：探讨正中神经刺激（MNS）对心肌梗死后室性心律失常的作用及其机制。方法：15只成年杂种犬制作心梗模型,4周后随机分为MNS1组和MNS2组,MNS1组单纯刺激正中神经,MNS2组刺激前离断双侧迷走神经。两组分别于刺激前后测量心室有效不应期（ERP）及室颤阈值。于基线期、刺激前后取血浆检测肿瘤坏死因子-α（TNF-α）、白细胞介素-6（IL-6）和乙酰胆碱（ACh）的水平。所有犬于实验终点取心室组织检测梗死周边区TNF-α、IL-6、ACh水平及NF-κB蛋白表达。结果：在正中神经刺激前后,MNS1组和MNS2组心室ERP无明显变化。MNS1组室颤阈值明显高于MNS2组[（20.3±3.7）Vvs（8.7±2.9）V,P〈0.01]。MNS1组梗死周边区测得TNF-α、IL-6、NF-κB水平低于MNS2组[TNF-α：（0.21±0.06）ng/mg vs（0.30±0.08）ng/mg,P〈0.05;IL-6：（0.16±0.07）ng/mg vs（0.26±0.08）ng/mg,P〈0.05;NF-κB：（0.25±0.05）vs（0.44±0.09）,P〈0.01],而ACh水平较MNS2升高[（18.0±3.9）ng/mg vs（10.0±3.5）ng/mg,P〈0.01]。结论：MNS可升高心梗犬的室颤阈值,该影响可能与胆碱能抗炎通路有关。

Objective：To explore the effect and mechanism of median nerve stimulation（MNS）on ventricular arrhythmia after myocardial infarction（MI）.Methods：Fifteen adult mongrel dogs were performed experimental MI.Four weeks later,the remaining dogs were randomly divided into MNS group 1 and MNS group 2.The MNS group 1 dogs only underwent MNS for 30 min.The MNS group 2 dogs underwent MNS for equal time with bilateral vagotomy previously.Ventricular electrophysiology and ventricular fibrillation threshold（VTF）were measured in the MNS group 1 dogs before and after MNS,and the same measurement was performed in the MNS group 2 dogs with bilateral vagotomy.The levels of tumor necrosis factor-alpha（TNF-α）,interleukin-6（IL-6）,acetylcholine（ACh）in blood were respectively tested in baseline,before and after MNS.At the end of the study,the levels of TNF-α,IL-6 and ACh and the expression of NF-κB were tested in the peri-infarct zone tissues.Results：There were no significant changes in the ventricular effective refractory period in the MNS group 1 and MNS group 2 dogs before and after MNS.VFT in the MNS group 1 was significantly higher than that in the MNS group 2（[20.3±3.7]Vvs[8.7±2.9]V,P〈0.01）.The levels of TNF-α,IL-6 and NF-κB were lower as TNF-α：（0.21±0.06）ng/mg vs（0.30±0.08）ng/mg,P〈0.05;IL-6：（0.16±0.07）ng/mg vs（0.26±0.08）ng/mg,P〈0.05;NF-κB：（0.25±0.05）vs（0.44±0.09）,P〈0.01.And the levels of ACh were higher in the peri-infarct zone tissues in the MNS group 1 dogs than that in the MNS group 2 dogs as（18.0±3.9）ng/mg vs（10.0±3.5）ng/mg,P〈0.01.Conclusion：MNS increases VFT in a canine model with MI.The effects of MNS on VFT might be associated with the cholingergic anti-inflammatory pathway.