Guo Yan-Jun, Su Sheng-Yong, Su Hong, Yang Pu, Li Jing, Xie Cai-Yun
Guangxi University of Chinese Medicine, Nanning 530001, China.
Guangxi Key Laboratory of Molecular Biology of Traditional Chinese Medicine, Nanning 530023.
Zhen Ci Yan Jiu. 2024;49(9):909-916. doi: 10.13702/j.1000-0607.20230789.
To observe effects of electroacupuncture (EA) on the activation of astrocytes and high mobility group protein B1(HMGB1)/Toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88) signaling pathway, as well as related cytokines in rats with cervical spondylosis radiculopathy(CSR), so as to explore the analgesic mechanism of EA in treating CSR.
Twenty-four male SD rats were randomly divided into blank, sham surgery, model, and EA groups, with 6 rats in each group. CSR rat model was established by using cervical spinal cord canal puncture method. On the 7 day after successful modeling, EA was applied to rats in the EA group at bilateral "Hegu"(LI4) and "Taichong"(LR3) for 20 minutes(1.5 Hz, 1 mA), once daily for 7 consecutive days. Before and after intervention, gait impairment scores and mechanical pain thresholds were assessed. HE staining was used to observe pathological changes in spinal cord tissue. Western blot was used to detect the expression of HMGB1, TLR4, MyD88, and glial fibrillary acidic protein (GFAP) in the spinal cord. ELISA was used to measure the contents of CXC chemokine ligand 1 (CXCL1), chemokine ligand 2 (CCL2), tumor necrosis factor (TNF)-α, and interleukin (IL)-1β in spinal cord. Immunofluorescence staining was used to observe GFAP protein positive expression in spinal cord tissue.
There was no significant difference of all indexes between the blank group and the sham surgery group. Compared with the sham surgery group, mechanical pain threshold of rats in the model group was decreased(<0.01), while gait impairment score, the contents of CXCL1, CCL2, TNF-α, IL-1β, protein expressions of HMGB1, TLR4, MyD88 and GFAP, and positive expression of GFAP in spinal cord tissue were increased (<0.01)；HE staining indicated severe overall morphological damage in the spinal cord of rats in the model group, with significant shrinkage of gray matter neurons, reduced number of Nissl bodies, and increased inflammatory cell infiltration. Compared with the model group, mechanical pain threshold in the EA group was increased (<0.01), while gait impairment score, the contents of CXCL1, CCL2, TNF-α, IL-1β, protein expressions of HMGB1, TLR4, MyD88 and GFAP, and positive expression of GFAP in spinal cord were reduced (<0.01)；HE staining showed more intact neuronal cell bodies, increased number of Nissl bodies, and reduced shrinkage of gray matter neurons, inflammatory cell infiltration, and microvascular dilation in the spinal cord of rats in the EA group.
EA can effectively alleviate pain in CSR rats, which is possibly by inhibiting astrocyte activation, HMGB1/TLR4/MyD88 signaling pathway, and reducing the release of related inflammatory cytokines, thus alleviating central sensitization in spinal segments.
观察电针（EA）对神经根型颈椎病（CSR）大鼠星形胶质细胞活化及高迁移率族蛋白B1（HMGB1）/Toll样受体4（TLR4）/髓样分化因子88（MyD88）信号通路以及相关细胞因子的影响，以探讨EA治疗CSR的镇痛机制。
将24只雄性SD大鼠随机分为空白组、假手术组、模型组和EA组，每组6只。采用颈椎椎管穿刺法建立CSR大鼠模型。造模成功后第7天，对EA组大鼠双侧“合谷”（LI4）和“太冲”（LR3）进行电针治疗20分钟（1.5赫兹，1毫安），每天1次，连续7天。干预前后评估步态障碍评分和机械痛阈。采用苏木精-伊红（HE）染色观察脊髓组织病理变化。采用蛋白质免疫印迹法检测脊髓中HMGB1、TLR4、MyD88和胶质纤维酸性蛋白（GFAP）的表达。采用酶联免疫吸附测定（ELISA）法检测脊髓中CXC趋化因子配体1（CXCL1）,趋化因子配体2（CCL2）、肿瘤坏死因子（TNF）-α和白细胞介素（IL）-1β的含量。采用免疫荧光染色观察脊髓组织中GFAP蛋白的阳性表达。
空白组与假手术组各项指标比较，差异无统计学意义。与假手术组比较，模型组大鼠机械痛阈降低（<0.01），步态障碍评分、CXCL1、CCL2、TNF-α、IL-1β含量、HMGB1、TLR4、MyD88和GFAP蛋白表达以及脊髓组织中GFAP阳性表达均升高（<0.01）；HE染色显示模型组大鼠脊髓整体形态损伤严重，灰质神经元明显萎缩，尼氏体数量减少，炎性细胞浸润增多。与模型组比较，EA组大鼠机械痛阈升高（<0.01），步态障碍评分、CXCL1、CCL2、TNF-α、IL-1β含量HMGB1、TLR4、MyD88和GFAP蛋白表达以及脊髓中GFAP阳性表达均降低（<0.01）；HE染色显示EA组大鼠脊髓神经元细胞体较完整，尼氏体数量增多，灰质神经元萎缩减轻，炎性细胞浸润及微血管扩张减少。
EA可有效减轻CSR大鼠疼痛，其机制可能是通过抑制星形胶质细胞活化、HMGB1/TLR4/MyD88信号通路，减少相关炎性细胞因子释放，从而减轻脊髓节段的中枢敏化。
