Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, The National Key Clinical Specialty, The Engineering Technology Research Center of Education Ministry of China, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Guangzhou, China.
Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, The National Key Clinical Specialty, The Engineering Technology Research Center of Education Ministry of China, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Guangzhou, China.
Neurobiol Dis. 2020 Sep;143:104945. doi: 10.1016/j.nbd.2020.104945. Epub 2020 May 16.
Deafferentation pain (DP), a typical neuropathic pain, occurs due to peripheral or central sensory nerve injury, which causes abnormal discharge of the upstream neurons or C fibers. Current treatment methods for DP have multiple side effects. Bone marrow mesenchymal stem cells (BMSC) have been used to treat neuropathic pain because of their ability to regulate neuroinflammation. Glial cell-derived neurotrophic factor (GDNF) is a neurotrophic mediator that exerts neuroprotective effects in neurological diseases. In this study, we investigated whether DP could be alleviated by BMSCs and the underlying mechanism. In vitro study, microglia was stimulated by lipopolysaccharide and then co-cultured with BMSC, GDNF or siRNA GDNF-BMSC. In vivo study, BMSC or siRNA GDNF-BMSC was transplanted intramedullarily on the 21st day after DP surgery. The expression of inflammatory-related factors were detected by RT-PCR and ELISA, RT-PCR,flow cytometry and immunofluorescence staining were performed to detect the expression of microglial surface markers, and Western blot was used to detect the expression levels of p-NF-kb, pPI3K, and pAKT. The pain-related behavioral changes were detected 7 days after transplantation. ELISA and RT-PCR results showed that the production of inflammatory cytokines in lipopolysaccharide-stimulated microglia and DP model plasma was downregulated, while anti-inflammatory mediators were upregulated significantly following pretreatment with BMSCs or GDNF. Flow cytometry, immunofluorescence staining, and RT-PCR results showed that BMSCs inhibited the microglial M1 phenotype and promoted the M2 phenotype by secreting GDNF. Furthermore, modulation functions of BMSCs involve inhibiting NF-κB while promoting PI3K /AKT signaling pathway activation. We found that our in vivo DP model was completely deafferent and BMSC administration clearly alleviated symptoms of DP. This function was also, at least partly, achieved by GDNF. The present studies demonstrate that BMSC can inhibit neuroinflammation by transforming microglial destructive M1 phenotype into regenerative M2 phenotype, and thus alleviate DP,likely by suppressing the NF-κB signaling pathway while promoting the PI3K/AKT signaling pathway activation through producing GDNF. The present findings are in support of the potential therapeutic application of BMSCs and the pharmaceutical application of GDNF for DP.
去传入神经痛（DP）是一种典型的神经病理性疼痛，发生于外周或中枢感觉神经损伤后，导致上游神经元或 C 纤维异常放电。目前 DP 的治疗方法存在多种副作用。骨髓间充质干细胞（BMSC）因其具有调节神经炎症的能力，已被用于治疗神经病理性疼痛。胶质细胞源性神经营养因子（GDNF）是一种神经营养介质，在神经疾病中发挥神经保护作用。在这项研究中，我们研究了 BMSC 是否可以缓解 DP 及其潜在机制。在体外研究中，用脂多糖刺激小胶质细胞，然后与 BMSC、GDNF 或 siRNA GDNF-BMSC 共培养。在体内研究中，DP 手术后第 21 天，经骨髓腔内移植 BMSC 或 siRNA GDNF-BMSC。通过 RT-PCR 和 ELISA 检测炎症相关因子的表达，通过 RT-PCR、流式细胞术和免疫荧光染色检测小胶质细胞表面标志物的表达，通过 Western blot 检测 p-NF-kb、pPI3K 和 pAKT 的表达水平。移植后 7 天检测疼痛相关行为变化。ELISA 和 RT-PCR 结果表明，脂多糖刺激的小胶质细胞和 DP 模型血浆中炎症细胞因子的产生下调，而预处理 BMSC 或 GDNF 后抗炎介质显著上调。流式细胞术、免疫荧光染色和 RT-PCR 结果表明，BMSC 通过分泌 GDNF 抑制小胶质细胞 M1 表型并促进 M2 表型。此外，BMSC 的调节功能涉及抑制 NF-κB 而促进 PI3K/AKT 信号通路激活。我们发现我们的体内 DP 模型完全去传入，BMSC 给药明显缓解 DP 症状。这种功能至少部分是通过 GDNF 实现的。本研究表明，BMSC 可以通过将小胶质细胞破坏性的 M1 表型转化为再生的 M2 表型来抑制神经炎症，从而缓解 DP，可能通过抑制 NF-κB 信号通路，同时通过产生 GDNF 促进 PI3K/AKT 信号通路激活。这些发现支持 BMSC 治疗 DP 的潜在应用和 GDNF 治疗 DP 的药物应用。
