Hu Rui-Bin, Long Meng-Yang, Diao Zhi-Jun, Wu Yu-Wei, Xue Si-Meng, Gao Xin-Yan, Qiao Hai-Fa
College of Acupuncture-moxibustion and Tuina, Shaanxi University of Chinese Medicine, Xianyang 712046, Shaanxi Province, China; Shaanxi Key Laboratory of Acupuncture and Medicine, Xianyang 712046, Shaanxi Province.
Shaanxi Key Laboratory of Acupuncture and Medicine, Xianyang 712046, Shaanxi Province; Traditional Chinese Medicine Master Research Institute, Shaanxi University of Chinese Medicine, Xianyang 712046, Shaanxi Province.
Zhen Ci Yan Jiu. 2023 Sep 25;48(9):833-42. doi: 10.13702/j.1000-0607.20221049.
To investigate the relationship between the sensitization state of acupoints on the surface of the myocardial ischemia (MI) model mice and the changes in the electrophysiological properties of the dorsal root ganglion (DRG) neurons in the corresponding spinal cord segment, and its underlying mechanism.
Sixty-eight male C57BL/6J mice were randomly divided into control and model groups (34 mice in each group). The model group received an intraperitoneal injection of 160 mg/kg isoproterenol (ISO) to establish the MI model, and the control group received an injection of the same dose of normal saline as the model group. After modeling for about 6 days, MI proportion was measured by HE staining to verify the pathological changes in the heart tissue. Evans blue (EB) dye was injected into the tail vein of mice to reflect the size, location, distribution, and number of exudates on the body surface. Then, whole-cell membrane currents, intrinsic excitability and membrane properties of different types of DRG neurons were evaluated by electrophysiological experiment .
Compared with the control group, the heart size was larger, with pathological outcomes showing enlarged myocardial hypertrophy, destroyed structure of cardiomyocytes, with mononuclear cell infiltration among the cardiomyocytes in the model group. Compared with the control group, the number of EB exudation points was significantly increased (<0.01), which were mainly concentrated in the epidermis near the T1-T5 segment of the spinal cord, "Feishu" (BL13), "Jueyinshu" (BL14) and "Xinshu" (BL15) in the model group. Compared with the control group, the rheobase and action potential amplitude (APA) of DRG medium-sized neurons were obviously decreased (<0.01, <0.05), while the whole-cell membrane currents, the spike numbers, the average instantaneous frequency, and the average discharge frequency were markedly increased (<0.01). There were no significant alterations in the membrane properties and intrinsic excitability induced by depolarized currents of small-sized neurons between groups. Compared with the control group, the whole-cell membrane currents, spike numbers, and the average instantaneous frequency were significantly increased in the model group(<0.05, <0.01) while rheobase was significantly decreased (<0.05) in DRG medium-sized neurons labeled with biotin and CGRP.
After the mice were modeled by ISO, the DRG medium-size neurons in the T1-T5 segment of the spinal cord may mediate the sensitization of acupoints on the body surface through their different neuronal membrane properties and intrinsic excitabilities.
探讨心肌缺血（MI）模型小鼠体表穴位敏化状态与相应脊髓节段背根神经节（DRG）神经元电生理特性变化及其潜在机制之间的关系。
68只雄性C57BL/6J小鼠随机分为对照组和模型组（每组34只）。模型组腹腔注射160mg/kg异丙肾上腺素（ISO）建立MI模型，对照组注射与模型组相同剂量的生理盐水。造模约6天后，通过HE染色测量MI比例以验证心脏组织的病理变化。将伊文思蓝（EB）染料注入小鼠尾静脉以反映体表渗出物的大小、位置、分布和数量。然后，通过电生理实验评估不同类型DRG神经元的全细胞膜电流、内在兴奋性和膜特性。
与对照组相比，模型组心脏体积增大，病理结果显示心肌肥厚、心肌细胞结构破坏、心肌细胞间有单核细胞浸润。与对照组相比，模型组EB渗出点数量显著增加（P<0.01），主要集中在脊髓T1-T5节段附近的表皮、“肺俞”（BL13）、“厥阴俞”（BL14）和“心俞”（BL15）。与对照组相比，DRG中型神经元的阈强度和动作电位幅度（APA）明显降低（P<0.01，P<0.05），而全细胞膜电流、峰电位数量、平均瞬时频率和平均放电频率显著增加（P<0.01）。两组间小型神经元去极化电流诱导的膜特性和内在兴奋性无明显改变。与对照组相比，模型组中用生物素和降钙素基因相关肽标记的DRG中型神经元的全细胞膜电流、峰电位数量和平均瞬时频率显著增加（P<0.05，P<0.01），而阈强度显著降低（P<0.05）。
ISO对小鼠造模后，脊髓T1-T5节段的DRG中型神经元可能通过其不同的神经元膜特性和内在兴奋性介导体表穴位的敏化。
