TNF-α上调脊髓SFKs在LDH诱导的中枢敏感化和神经根性疼痛中的作用及机制

Lumbar disc herniation (LDH) is a major cause of radicular pain (RP). The role of peripheral sensitization in this process has been intensively studied. However, whether central sensitization is involved in RP is still unclear. We have reported that the activation of Src-family kinases (SFKs) is vital for inducing long term potentiation (LTP) of spinal synaptic transimission which represents central sensitization. Recently, we found LTP of spinal postsynaptic potential was highly positively correlated with the time course of pain in rats with LDH. Central sensitization that mediated by activation of spinal SFKs may be involved in LDH induced hyperalgesia. Cell and integral experiments showed TNF-α increased p-SFKs expression in a dose dependent manner. Therefore, TNF-α may be involved in LDH induced central sensitization and RP by up-regulating spinal SFKs. In the present study, from the level of in vivo and in vitro, we will examine the role of SFKs and its’ family members in LDH induced central sensitization and RP, then discuss the mechanism of TNF-α and downstream signal pathways up-regulating SFKs, inducing central sensitization and pain, thus explore new targets and strategies for RP treatment.

腰椎间盘突出症（LDH）是神经根性疼痛(RP)的主要病因，外周敏感化作为RP产生的机制已得到深入研究，中枢敏感化是否参与了RP的发生发展尚不清楚。申请人早期研究发现酪氨酸家族激酶（SFKs）活化是脊髓背角突触传递效率长时程增强（LTP），即中枢敏感化产生的重要原因。最近又发现LDH大鼠脊髓背角突触后电位出现LTP，并与疼痛的产生时程高度正相关；脊髓SFKs活化介导的中枢敏感化可能参与LDH诱导的痛觉过敏；细胞和整体实验提示TNF-α剂量依赖性的上调p-SFKs表达。提示：TNF-α可能通过上调脊髓SFKs参与了LDH诱导的中枢敏感化和RP。本研究拟从在体和离体水平，研究脊髓背角SFKs及其家族成员在LDH诱导的中枢敏感化和RP中的作用；探讨 TNF-α及其下游信号通路上调SFKs从而引起中枢敏感化和疼痛的机制，以期为治疗RP提供新的靶点和策略。

腰椎间盘突出症（LDH）是神经根性疼痛的主要病因，其机制尚不清楚，临床也缺乏有效的治疗手段。本研究用自体髓核（NP）移植的方法复制大鼠LDH模型，痛行为学测试方法检测后肢机械性撤足阈值（PWT）和热撤足潜伏期（PWL），在体电生理方法记录脊髓背角C纤维诱发的场电位，Western blotting、免疫荧光染色和ELISA方法检测脊髓组织中蛋白质表达情况。研究发现：自体NP移植后2-20d，同侧后肢PWT和PWL明显下降，提示NP移植大鼠出现机械性痛觉超敏和热痛觉过敏；与sham组相比，NP移植组大鼠脊髓背角C纤维诱发场电位幅度明显增加，痛觉传递效率明显提高，提示中枢敏感化可能参与了神经根性疼痛的发生；NP移植后，脊髓背角p-SFKs，p-p38表达明显增加，且仅仅表达在脊髓背角小胶质细胞，SFKs/p38抑制剂缓解疼痛症状，抑制脊髓背角小胶质细胞的激活，抑制脊髓背角致炎细胞因子TNF-α, IL-1β和IL-6的表达。同时我们发现连续腹腔注射葛根素通过抑制ERK依赖的胶质细胞的活化和致炎细胞因子的表达治疗神经根性疼痛。本研究首次证实了中枢敏感化参与神经根性疼痛的发生发展，并发现脊髓背角SFKs表达增加通过激活小胶质细胞和促进炎性反应诱导中枢敏感化和慢性疼痛的产生；传统中药葛根素可通过抑制胶质细胞及神经炎症反应治疗神经根性疼痛。本研究为临床治疗神经根性疼痛提供了新的靶点和理论依据。