葛根素抑制背根神经节Nav1.7上调治疗神经根性疼痛*

Puerarin alleviates radicular pain by inhibiting Nav1.7 upregulationin the DRG*

摘要:

目的：探究传统中药葛根素对腰椎间盘突出症引起的神经根性疼痛的作用及机制。方法：用自体髓核（neucleus pulposus, NP）移植的方法复制大鼠腰椎间盘突出症的模型，连续7天腹腔注射葛根素（100 mg/kg, qd）观察镇痛效果；机械性缩足阈值（paw withdrawal threshold, PWT）和热缩足潜伏期（paw withdrawal latency, PWL）作为痛觉阈值检测指标；ELISA法检测背根神经节（dorsal root ganglia, DRG）和脑脊液（cerebrospinal fluid, CSF）中肿瘤坏死因子-α （tumor necrosis factor-α, TNF-α）的含量；Western blot方法检测DRG组织TNF-α和磷酸化核转录因子-κB（phosphorylated-nucleus factor-κB, p-NF-κB）表达水平；免疫荧光染色方法检测DRG电压门控钠通道Nav1.7表达情况。结果：NP移植组大鼠手术同侧DRG中Nav1.7表达上升，同侧DRG组织和CSF中TNF-α含量显著增加；葛根素明显缓解NP移植引起的单侧的机械性痛觉过敏和热痛觉超敏；葛根素降低同侧DRG中TNF-α、p-NF-κB （p-p65）和Nav1.7的表达；鞘内注射TNF-α（0.3 ng, q6h, 持续7d）阻断了葛根素的镇痛作用，并抑制了葛根素引起的Nav1.7的降低。结论：葛根素可抑制背根神经节Nav1.7上调治疗神经根性疼痛。

Abstract:

Objective: To explore the role and mechanism of traditional Chinese medicine puerarin in radicular pain induced by lumbar disc herniation. Methods: Rat model of lumbar disc herniation was induced by autologous nucleus pulposus (NP) implantation, and puerarin was successively delivered for 7 days (ip, 100 mg/kg, qd); Pain thresholds were assessed by mechanical paw withdrawal threshold (PWT) and thermal paw withdrawal latency (PWL); Tumor necrosis factor-α (TNF-α) level in the dorsal root ganglia (DRG) and cerebrospinal fluid (CSF) was detected by enzyme-linked immunosorbent assay (ELISA). The expression of TNF-α and p-NF-κB (p-p65) in DRG was measured by western blotting analysis; Voltage gated sodium channel Nav1.7 expression was detected by immunofluorescence. Results: Nav1.7 expression in the DRG was increased in rats with NP implantation; TNF-α level in the DRG and CSF was increased in rats with NP implantation; Puerarin alleviated mechanical allodynia and thermal hyperalgesia induced by NP implantation; Puerarin reduced TNF-α, p-p65 and Nav1.7 expression; Intrathecal delivery of TNF-α (0.3 ng, q6h, for 7days) significantly obscured the effect of puerarin on Nav1.7 expression. Conclusion: Puerarin alleviates radicular pain by inhibiting Nav1.7 upregulation in the DRG.