OBJECTIVES In cardiac ischemia, acute inflammatory responses further increase the detrimental effect on myocardial tissue. Since vagus nerve stimulation (VS) attenuates inflammatory responsiveness this study examines the effect of VS on myocardial damage development in a cardiac ischemia-reperfusion (IR) mouse model. METHODS 54 male C57Bl/6j mice were subjected to an IR procedure with or without prior VS. The effects on inflammatory responsiveness, infarct size, cardiac function, neutrophils, lymphocytes and vascular endothelial growth factor (VEGF) in the infarcted myocardium were measured at 48 h after intervention. Group results were compared with unpaired Mann-Whitney or Kruskall-Wallis test. RESULTS A significant decrease in inflammatory responsiveness was not verified by decreased TNFα levels in blood from VS and IR treated mice. The percentage infarct size over area at risk was smaller in the group with VS + IR compared with IR (22.4 ± 10.2% vs 37.6 ± 9.0%, p = 0.003). The degree of the reduction in cardiac function was not different between the IR groups with or without VS and no group differences were found in amounts of neutrophils, CD3+ lymphocytes and VEGF in the reperfused mouse heart. CONCLUSION The present study does not provide clear evidence of a reducing role for VS on cardiac function loss. This could mean that VS has a less inhibiting effect on myocardial inflammation than may be expected from the literature.

中文翻译：

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迷走神经刺激对小鼠心肌缺血再灌注模型组织损伤及功能丧失的影响

目的 在心脏缺血中，急性炎症反应进一步增加对心肌组织的不利影响。由于迷走神经刺激 (VS) 减弱炎症反应性，本研究在心脏缺血再灌注 (IR) 小鼠模型中检查了 VS 对心肌损伤发展的影响。方法 对 54 只雄性 C57Bl/6j 小鼠进行 IR 程序，有或没有先前的 VS。在干预后48小时测量对梗死心肌的炎症反应性、梗死面积、心脏功能、中性粒细胞、淋巴细胞和血管内皮生长因子（VEGF）的影响。组结果与未配对的 Mann-Whitney 或 Kruskall-Wallis 检验进行比较。结果 VS 和 IR 治疗小鼠血液中 TNFα 水平的降低并未证实炎症反应性的显着降低。与 IR 相比，VS + IR 组的梗死面积占风险区域的百分比更小（22.4 ± 10.2% vs 37.6 ± 9.0%，p = 0.003）。有或无 VS 的 IR 组之间的心脏功能降低程度没有差异，并且在再灌注的小鼠心脏中，中性粒细胞、CD3+ 淋巴细胞和 VEGF 的数量没有发现组间差异。结论 本研究没有提供明确的证据证明 VS 对心脏功能丧失有降低作用。这可能意味着 VS 对心肌炎症的抑制作用比文献中预期的要小。有或无 VS 的 IR 组之间的心脏功能降低程度没有差异，并且在再灌注的小鼠心脏中，中性粒细胞、CD3+ 淋巴细胞和 VEGF 的数量没有发现组间差异。结论 本研究没有提供明确的证据证明 VS 对心功能丧失有降低作用。这可能意味着 VS 对心肌炎症的抑制作用比文献中预期的要小。有或无 VS 的 IR 组之间的心脏功能降低程度没有差异，并且在再灌注的小鼠心脏中，中性粒细胞、CD3+ 淋巴细胞和 VEGF 的数量没有发现组间差异。结论 本研究没有提供明确的证据证明 VS 对心脏功能丧失有降低作用。这可能意味着 VS 对心肌炎症的抑制作用比文献中预期的要小。