Department of Biology, College of Sciences, Shiraz University, Shiraz, Iran.
Department of Physiology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
BMC Cardiovasc Disord. 2022 Apr 19;22(1):181. doi: 10.1186/s12872-022-02594-w.
The influence of cutting the sub-diaphragmatic branch of the vagus nerve on heart rate variability (HRV) and inflammatory reaction to severe hemorrhagic shock has not been determined prior to this study.
Male Sprague-Dawley rats were divided into four groups of Sham, sub-diaphragmatic vagotomized (Vag), subacute (135 ± 2 min) hemorrhagic shock (SHS), and sub-diaphragmatic vagotomized with SHS (Vag + SHS). Hemodynamic parameters were recorded and HRV calculated during multiple phases in a conscious model of hemorrhagic shock. The expressions of TNF-α and iNOS were measured in the spleen and lung tissues at the conclusion of the protocol.
Decreases in blood pressure during blood withdrawal were identical in the SHS and Vag + SHS groups. However, heart rate only decreased in the Nadir-1 phase of the SHS group. HRV indicated increased power in the very-low, low, and high (VLF, LF, and HF) frequency bands during the Nadir-1 phase of the SHS and Vag + SHS groups, albeit the values were higher in the SHS group. In the recovery phase, the HF bands were only lower in the SHS group. After hemorrhagic shock followed by resuscitation, the expression of TNF-α and iNOS increased in the spleen and lung of the SHS group, and the expression of these genes was significantly lower in the Vag + SHS group than in the SHS group.
Parasympathetic activity increases during the hypotensive phase of hemorrhagic shock, whereas the cardiac vagal tone decreases in the recovery phase. Sub-diapragmatic vagotomy blunts the cardiac vagal tone during hemorrhagic shock, but its effect is reversed in the recovery phase. The vagus nerve plays a role in proinflammatory responses in the lungs and spleen in subacute hemorrhagic shock followed by resuscitation.
在本研究之前，尚未确定切断迷走神经膈下分支对心率变异性（HRV）和严重失血性休克炎症反应的影响。
雄性 Sprague-Dawley 大鼠分为 4 组：假手术组（Sham）、膈下迷走神经切断组（Vag）、亚急性（135±2 分钟）失血性休克组（SHS）和膈下迷走神经切断加 SHS 组（Vag+SHS）。在清醒失血性休克模型中，记录多个阶段的血流动力学参数并计算 HRV。在方案结束时测量脾和肺组织中 TNF-α 和 iNOS 的表达。
在 SHS 和 Vag+SHS 组中，抽血过程中血压下降相同。然而，只有在 SHS 组的 Nadir-1 期，心率才会下降。HRV 表明，在 SHS 和 Vag+SHS 组的 Nadir-1 期，非常低、低和高（VLF、LF 和 HF）频带的功率增加，尽管 SHS 组的值更高。在恢复阶段，仅 SHS 组的 HF 频段较低。在失血性休克后复苏后，TNF-α 和 iNOS 在 SHS 组的脾和肺中表达增加，而 Vag+SHS 组的这些基因表达明显低于 SHS 组。
在失血性休克的低血压期，副交感神经活动增加，而在恢复阶段，心脏迷走神经张力降低。膈下迷走神经切断术在失血性休克期间减弱心脏迷走神经张力，但在恢复阶段其作用逆转。迷走神经在亚急性失血性休克后复苏时的肺部和脾脏的促炎反应中起作用。
