基于脊髓小胶质细胞P2X4受体介导BDNF/TrkB-KCC2通路探讨低频电针干预糖尿病神经痛的作用机制

Diabetic neuropathic pain (DNP) is one of the most common complications of diabetes, and severely affects the patients’ life quality. Studies show that P2X4 receptor of microglia in spinal dorsal cord horn plays an important role in its mechanisms. We previously found that microglia in spinal dorsal cord horn was increased in DNP rats, and low frequency electroacupuncture could effectively downregulated, but the mechanism is unclear. Studies show that BDNF/TrkB-KCC2 signal pathway participate in diabetic neuropathic pain, and initial studies show that microglia P2X4 receptor regulated BDNF/TrkB-KCC2 signal pathway. The project is to adopt a rat model with DNP, the behavior of pain sensitization, microglia P2X4 receptor in spinal dorsal cord horn expression and activation, activation of BDNF/TrkB-KCC2 pathway, as well as the effects of low frequency electroacupuncture on these processes were studied, and agonist or inhibitor were applied, together to clear the mechanism of low frequency electroacupuncture on intervention on diabetic neuropathic pain based on its regulation of P2X4 receptor in microglia of spinal cord dorsal horn through BDNF/TrkB-KCC2 pathway. These will provide a scientific foundation for the elucidation of the mechanism underlying electroacupuncture treatment for DNP.

糖尿病神经痛（DNP）是糖尿病最常见的并发症之一，发病率高，严重影响患者生存质量。脊髓背角小胶质细胞P2X4受体在DNP发生机制中起着重要作用。我们前期研究发现在DNP大鼠脊髓背角小胶质细胞阳性表达增多，低频电针能有效抑制其表达，但电针对小胶质细胞内信号通路的干预机制尚不清楚。研究表明BDNF/TrkB-KCC2通路参与糖尿病神经痛，初步研究表明脊髓背角小胶质细胞P2X4介导BDNF/TrkB-KCC2通路调控参与神经痛。本项目拟采用DNP大鼠模型，观察DNP大鼠痛行为、脊髓背角小胶质细胞P2X4受体、BDNF、TrkB、KCC2表达变化及低频电针对其的干预作用，并运用相关拮抗剂或激动剂开展验证实验，明确基于脊髓背角小胶质细胞P2X4受体介导BDNF/TrkB-KCC2通路的调控机制和低频电针的干预机制，将为电针治疗DNP的机理阐释提供科学基础。

临床上糖尿病发病率越来越高，糖尿病神经痛（DNP）是其常见的并发症之一，目前DNP的发病机制尚不完全明确，且缺乏有效的治疗方法。电针作为控制慢性疼痛的主要手段之一，在临床上治疗DNP应用并不广泛。本研究通过腹腔注射链脲佐菌素建立DNP大鼠模型，探究DNP的发病机制及电针治疗DNP的部分机制。观察大鼠脊髓背角小胶质细胞P2X4受体、BDNF、TrkB和KCC2蛋白表达变化，结合小胶质细胞抑制剂和P2X4受体抑制剂，验证大鼠脊髓背角小胶质细胞P2X4受体在DNP大鼠模型中的作用；观察电针对DNP大鼠脊髓背角小胶质细胞P2X4受体、BDNF、TrkB和KCC2蛋白表达的影响，以明确电针是否通过干预脊髓背角小胶质细胞P2X4受体进而调控BDNF/TrkB-KCC2通路从而控制糖尿病神经痛。研究结果显示，DNP大鼠脊髓背角小胶质细胞P2X4受体、BDNF、TrkB蛋白表达增加，KCC2蛋白表达减少，小胶质细胞抑制剂米诺环素及P2X4受体抑制剂5-BDBD注射后DNP大鼠热痛阈上升，小胶质细胞、P2X4受体及BDNF蛋白表达减少；电针干预后DNP大鼠热痛阈升高，小胶质细胞、P2X4受体、BDNF、TrkB蛋白表达减少，KCC2蛋白表达增加。该项目研究结果阐释了DNP发病的部分机制，同时也阐明了电针治疗DNP的部分机制，以推动电针疗法更好、更广泛地应用于糖尿病神经痛临床治疗。