基于脊髓中枢敏化探讨烙灸干预腰椎间盘突出症慢性疼痛的机制

Exploring the mechanism of branding moxibustion intervention for chronic pain in lumbar disc herniation based on central sensitization of the spinal cord

目的探讨烙灸对大鼠腰椎间盘突出症慢性疼痛中枢敏化的影响。方法将45只健康雄性SD大鼠随机分为空白对照组、模型对照组和烙灸组,每组15只。模型对照组和烙灸组大鼠进行腰椎间盘突出症慢性疼痛中枢敏化造模。术后30 d证实造模成功后,烙灸组大鼠给予腰椎局部烙灸,每天1次,每次10 min,连续干预60 d;空白对照组、模型对照组不予干预。实验过程中观察各组大鼠行为学并检测左侧足底触觉痛阈值;术后90 d处死各组大鼠,取L_(4~6)节段脊髓组织,HE染色观察脊髓组织病理形态,ELISA法检测脊髓组织中白细胞介素-1β(IL-1β)、肿瘤坏死因子-α(TNF-α)含量,免疫组化法检测脊髓中小胶质细胞标记物Iba1和星形胶质细胞标记物胶质纤维酸性蛋白(GFAP)表达情况。结果术后30~90 d,模型对照组与烙灸组大鼠左侧足底触觉痛阈值均明显低于同期空白对照组(P均<0.05),其中术后50 d内逐渐降低,术后50 d后逐渐升高,术后70 d后趋于稳定,但烙灸组术后40~90 d左侧足底触觉痛阈值均明显高于同期模型对照组(P均<0.05)。HE染色显示模型对照组脊髓灰质区神经元固缩,少量神经元坏死、消失,尼氏小体数量减少,神经胶质细胞数量增多;烙灸组脊髓损伤较模型组轻。模型对照组大鼠脊髓组织中IL-1β、TNF-α含量和GFAP、Iba1表达平均光密度值均明显高于空白对照组(P均<0.05),烙灸组均明显低于模型对照组(P均<0.05)。结论烙灸疗法改善腰椎间盘突出症疼痛的机制与抑制脊髓胶质细胞活化,减少炎症因子分泌抑制炎症反应,从而减轻中枢敏化有关。

Objective It is to investigate the effect of branding moxibustion on central sensitization of chronic pain in rats with lumbar intervertebral disc herniation.Methods Forty-five healthy male SD rats were randomly divided into a blank control group,a model control group and a branding group,with 15 rats in each group.The rats in the model control group and the branding moxibustion group were modeled for central sensitization of chronic pain in lumbar disc herniation.After the successful modeling was confirmed 30 d after surgery,the rats in the branding moxibustion group were given local branding moxibustion on the lumbar spine,once a day,10 min per time,continuously treated for 60 days.The blank control group and the model control group were not intervened.The behavior of the rats in each group during the experiment was observed,and the tactile pain thresholds of the left plantar were detected.The rats were executed 90 d after the operation,and their spinal cord tissues of L_(4-6) segments were taken to observe the histopathological morphology of the spinal cord by HE staining.The levels of interleukin-1β(IL-1β)and tumor necrosis factor-α(TNF-α)in spinal cord tissues were detected by ELISA,and the expression of microglial cell marker Iba1 and astrocyte marker glial fibrillary acidic protein(GFAP)in spinal cord was detected by immunohistochemistry.Results From 30 to 90 days after surgery,the left plantar tactile pain thresholds of both the model control group and the branding moxibustion group were significantly lower than those of the blank control group during the same period(all P<0.05),which gradually decreased within 50 days after surgery,gradually increased in 50 days after surgery,and stabilized in 70 days after surgery,but the left plantar tactile pain thresholds of the branding moxibustion group were significantly higher than those of the model control group during 40 to 90 days after surgery(all P<0.05).HE staining showed that the neurons in the gray matter area of the spinal cord of the model control group were shrunken,a small number of neurons were necrotic and disappeared,and the number of niche bodies was reduced and the number of glial cells was increased;the spinal cord injury in the branding moxibustion group was lighter than that of the model group.The contents of IL-1β,TNF-α,and the mean optical density values of GFAP and Iba1 expression in the spinal cord tissues of the rats of the model control group were significantly higher than those of the blank control group(all P<0.05),and those of the branding moxibustion group were significantly lower than those of the model control group(all P<0.05).Conclusion The mechanism by which branding moxibustion therapy improves the pain of lumbar disc herniation is related to inhibiting the activation of spinal cord glial cells,reducing the secretion of inflammatory factors and inhibiting the inflammatory response,thereby reducing the occurrence of central sensitization.