辅助T细胞分化调节在针刺治疗神经病理痛中的机制研究

CD4+ T cells can differentiated into type 1 or type 2 helper T cells by stimulation. Interferon-γ (IFN-γ), released by type 1 helper T (Th1) cells, can evoke spinal P2X4R+ microglia activation, which is regarded as the key factor in triggering and maintaining neuropathic pain. While type 2 helper T cells can inhibit Th1 cell differentiation and attenuate spinal cord inflammation. Furthermore, the Th cell differentiation can be regulated by adrenergic/cholinergic nerve. In the previous work, we found that acupuncture can not only relieve chronic constriction injury (CCI) induced pain hypersensitivity by inhibiting spinal IFN-γ over-expression, but also regulate inflammatory immune response by activating adrenergic/cholinergic neural pathway. Based on all above, we proposed that acupuncture may regulate Th cell differentiation by activating adrenergic/cholinergic nerve, which consequently relieve neuropathic pain. In this project, we intend to use CCI model and find the effect of acupuncture on their pain threshold, spinal IFN-γ, and Th cell differentiation in peripheral blood. Furthermore, we plan to use interventions like Th cell differentiation modulators and adrenergic /cholinergic neurotransmitter blockers, to further make it sure that whether the regulation of Th cell differentiation is involved in the effect of acupuncture treatment. This study will reveal new mechanisms of acupuncture treatment in the perspective of neuroimmunomodulation, and provide theoretical basis for optimizing the acupuncture treatment of neuropathic pain.

CD4+ T细胞可分化为1型（Th1）或2型（Th2）辅助T细胞，Th1细胞释放γ-干扰素(IFN-γ)引起脊髓P2X4R+小胶质细胞活化是产生并维持神经病理痛的关键， 而Th2细胞能抑制Th1细胞分化并减轻脊髓炎症，且Th细胞分化受肾上腺素/胆碱能神经调节。我们前期工作发现针刺不仅能抑制慢性缩窄损伤(CCI)引起的脊髓IFN-γ过度释放并缓解神经病理痛；还能激活肾上腺素/胆碱能神经调节炎性免疫反应。据此我们提出针刺通过激活肾上腺素/胆碱能神经调节Th细胞分化，减少脊髓IFN-γ释放并缓解神经病理痛的假说。本项目通过观察针刺对CCI模型大鼠痛阈、脊髓IFN-γ及外周血Th细胞分化的影响，并采用调节Th细胞分化，阻断肾上腺素/胆碱能神经等干预手段，明确Th细胞分化调节是否是针刺治疗神经病理痛的重要机制。本研究将从神经免疫调节角度揭示针刺治疗的新机制，并为优化神经病理痛的针刺治疗提供理论依据。

CD4+ T细胞可分化为1型(Th1)或2型(Th2)辅助T细胞，Th1细胞释放的γ-干扰素(IFN-γ)引起脊髓P2X4R+小胶质细胞活化是产生并维持神经病理痛的关键， 而Th2细胞能抑制Th1细胞分化，并促进Th细胞向Th2细胞方向分化，减轻周围神经损伤引起的脊髓炎症。因此，抑制Th1细胞分化可能是针刺治疗神经病理痛的重要机制。我们实验证明，电针治疗CCI模型动物7天后，无论是脊髓还是外周血Th1细胞相关细胞因子IFN-γ表达均受到显著抑制，而Th2细胞相关细胞因子IL-4及IL-10则表达增高。血脑屏障通透性检测表明，CCI模型动物脊髓血脑屏障通透增高，电针治疗3天后明显好转，持续治疗7天后，血脑屏障通透性恢复到假手术组水平。同时，外周血细胞流式细胞仪检测表明，电针治疗CCI模型动物3天后，Th1细胞呈下降趋势，治疗7天后，Th1细胞显著低于CCI模型组，Th1/Th2比例明显下降，与假手术组相当。利血平腹腔注射化学阻断交感神经后，逆转了电针治疗抑制痛觉过敏的作用，并阻断了电针抑制Th1细胞相关细胞因子IFN-γ的作用。且单侧迷走神经切断术也减弱了电针缓解CCI模型鼠痛觉过敏作用，并减轻电针抑制Th1细胞相关细胞因子IFN-γ的作用。以上实验证明，电针治疗通过调节交感及迷走神经调节Th细胞分化，抑制Th1细胞，减少IFN-γ释放，缓解周围神经损伤引起的痛觉过敏。