Cheng Lian-Zhi, Zhou Jia-Mei, Ma Jun-Long, Wang Fan-Jing, Cheng Kai, Chen Qian, Yuan Hui-Lun, Jiang Ai-Juan
School of Integrated Traditional Chinese and Western Medicine, Anhui University of Traditonal Chinese Medicine Hefei 230012, China.
School of Integrated Traditional Chinese and Western Medicine, Anhui University of Traditonal Chinese Medicine Hefei 230012, China Institute of Integrated Traditional Chinese and Western Medicine, Anhui Academy of Chinese Medicine Hefei 230012, China.
Zhongguo Zhong Yao Za Zhi. 2022 May;47(9):2533-2540. doi: 10.19540/j.cnki.cjcmm.20220119.702.
Neuropathic pain is one of the common complications of diabetes. Tetrahydropalmatine(THP) is a main active component of Corydalis Rhizoma with excellent anti-inflammatory and pain-alleviating properties. This study aims to investigate the therapeutic effect of THP on diabetic neuropathic pain(DNP) and the underlying mechanism. High-fat and high-sugar diet(4 weeks) and streptozotocin(STZ, 35 mg·kg~(-1), single intraperitoneal injection) were employed to induce type-2 DNP in rats. Moreover, lipopolysaccharide(LPS) was used to induce the activation of BV2 microglia in vitro to establish an inflammatory cellular model. Fasting blood glucose(FBG) was measured by a blood glucose meter. Mechanical withdrawal threshold(MWT) was assessed with von Frey filaments, and thermal withdrawal latency(TWL) with hot plate apparatus. The protein expression levels of OX42, inducible nitric oxide synthase(iNOS), CD206, p38, and p-p38 were determined by Western blot, the fluorescence expression levels of OX42 and p-p38 in the dorsal horn of the rat spinal cord by immunofluorescence, the mRNA content of p38 and OX42 in rat spinal cord tissue by qRT-PCR, and levels of nitric oxide(NO), interleukin-1β(IL-1β), interleukin-6(IL-6), tumor necrosis factor-α(TNF-α), interleukin-10(IL-10), and serum fasting insulin(FINS) by enzyme-linked immunosorbent assay(ELISA). RESULTS:: showed that the mo-del group demonstrated significant decrease in MWT and TWL, with pain symptoms. THP significantly improved the MWT and TWL of DNP rats, inhibited the activation of microglia and p38 MAPK signaling pathway in rat spinal cord, and ameliorated its inflammatory response. Meanwhile, THP promoted the change of LPS-induced BV2 microglia from the pro-inflammatory M1 phenotype to the anti-inflammatory M2 phenotype, suppressed the activation of the p38 MAPK signaling pathway, decreased the expression levels of inflammatory factors NO, IL-1β, IL-6, and TNF-α, and increased the expression level of anti-inflammatory factor IL-10. The findings suggested that THP can significantly ameliorate the pain symptoms of DNP rats possibly by inhibiting the inflammatory response caused by M1 polarization of microglia via the p38 MAPK pathway.
神经病理性疼痛是糖尿病常见的并发症之一。延胡索乙素（THP）是延胡索的主要活性成分，具有出色的抗炎和止痛特性。本研究旨在探讨THP对糖尿病性神经病理性疼痛（DNP）的治疗作用及其潜在机制。采用高脂高糖饮食（4周）和链脲佐菌素（STZ，35 mg·kg⁻¹，单次腹腔注射）诱导大鼠2型DNP。此外，使用脂多糖（LPS）在体外诱导BV2小胶质细胞活化，以建立炎症细胞模型。用血糖仪测量空腹血糖（FBG）。用von Frey细丝评估机械撤针阈值（MWT），用热板仪评估热撤针潜伏期（TWL）。通过蛋白质免疫印迹法测定OX42、诱导型一氧化氮合酶（iNOS）、CD206、p38和p-p38的蛋白表达水平，通过免疫荧光法测定大鼠脊髓背角中OX42和p-p38的荧光表达水平，通过qRT-PCR测定大鼠脊髓组织中p38和OX42的mRNA含量，通过酶联免疫吸附测定（ELISA）测定一氧化氮（NO）、白细胞介素-1β（IL-1β）、白细胞介素-6（IL-6）、肿瘤坏死因子-α（TNF-α）、白细胞介素-10（IL-10）和血清空腹胰岛素（FINS）水平。结果显示：模型组MWT和TWL显著降低，出现疼痛症状。THP显著改善了DNP大鼠的MWT和TWL，抑制了大鼠脊髓小胶质细胞的活化和p38丝裂原活化蛋白激酶（MAPK）信号通路，并改善了其炎症反应。同时，THP促进了LPS诱导的BV2小胶质细胞从促炎M1表型向抗炎M2表型的转变，抑制了p38 MAPK信号通路的活化，降低了炎症因子NO、IL-1β、IL-6和TNF-α的表达水平，并增加了抗炎因子IL-10的表达水平。这些研究结果表明，THP可能通过p38 MAPK途径抑制小胶质细胞M1极化引起的炎症反应，从而显著改善DNP大鼠的疼痛症状。
