Vagus Nerve Stimulation in Early Stage of Acute Myocardial Infarction Prevent Ventricular Arrhythmias and Cardiac Remodeling

Figures

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  Figure 1. Timeline of the experimental protocol. ICD, implantable cardioverter defibrillators; LAD, left anterior descending coronary artery; VNS, vagus nerve stimulation; VF, ventricular fibrillation; LLVNS, low level left vagus nerve stimulation; MI, myocardial infarction.

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  Figure 2. The occurrence of VAs in the MI and MI+LLVNS groups. (A) The occurrence of VF, VT, NSVT, and PVC between the MI group (n = 6) and the MI+LLVNS group (n = 5) (*p < 0.05). (B) Example of an IEGM of ventricular fibrillation detected by the ICD and terminated by an ICD shock. The blue arrow shows the VF detected; the red arrow indicates the shock by the device, which restores the sinus rhythm. VAs, ventricular arrhythmias; VF, ventricular fibrillation; VT, ventricular tachycardia; NSVT, non-sustained ventricular tachycardia; PVC, premature ventricular contraction; ICD, implantable cardioverter defibrillators; LLVNS, low level left vagus nerve stimulation; MI, myocardial infarction.

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  Figure 3. Typical examples and densities of of TH-, GAP43- and NF-positive nerve fibers. (A) Border of myocardial injury was stained with hematoxylin and eosin (HE) as revealed by infiltration of inflammatory cells. (B–D): Increased density of TH-, GAP 43- and NF-positive nerve fibers at the border of myocardial injury, respectively. (E–G): Densities of TH-, GAP43- and NF-positive nerve fibers in three groups. The asterisk (*) indicates an artery in the cardiac tissue. Arrows in (A) indicate infiltration of inflammatory cells. Arrows in (B–D) indicate of TH-, GAP 43- and NF-positive nerve fibers separately. #compared with those in the sham operation, p < 0.05. +compared with those in MI group p < 0.05. TH, tyrosine hydroxylase; GAP43, growth associated protein 43; NF, neurofilament; LLVNS, low level left vagus nerve stimulation; MI, myocardial infarction. MI group (n = 6), MI+LLVNS group (n = 5), Sham operation group (n = 5).

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  Figure 4. LLVNS regulates the expression of genes. (A) The heat map of DEGs in the cardiac tissue (p < 0.05, 1.5 fold or more) between the MI and MI+LLVNS groups. (B) The verification of some DEGs identified in microarray analyses by RT-PCR analyses. (C) A pie chart of gene ontology clustering for the DEGs shown in (A). *p < 0.05. DEGs, differentially expressed genes; LLVNS, low level left vagus nerve stimulation; MI, myocardial infarction. MI group (n = 6), MI+LLVNS group (n = 5).

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  Figure 5. KEGG pathway analysis of up and down regulated genes with a fold change of at least 2 in the dogs of MI+LLVNS group (n = 5) compared with MI group (n = 6). KEGG, Kyoto encyclopedia of genes and genomes; LLVNS, low level left vagus nerve stimulation; MI, myocardial infarction.