Netrin-1在电针延缓退变腰椎间盘神经纤维内向生长中的作用及其信号转导机制研究

Lumbar intervertebral disc degenerative diseases are clinical multiple and easy relapse. So researches on prevention and treatment of lumbar intervertebral disc degeneration have been the focus of attention by the international research field. How to delay the intro-growth of myelinated nerve fibers after lumbar intervertebral disc degeneration and relieve disc pain have very important practical significance. Our preliminary studies showed that upregulation of netrin-1 as axon guidance factor in dorsal root ganglion corresponding to degenerated intervertebral disc was closely related to inhibition of intro-growth of myelinated nerve fibers by electroacupuncture applying lumbar disc degeneration model, provided a new opportunity for the study of electroacupuncture on lumbar intervertebral disc degeneration. This project is to clarify the key role of netrin-1 on inhibition of intro-growth of myelinated nerve fibers by electroacupuncture in the degenerated lumbar intervertebral disc, to study the opioid mechanism of electroacupuncture stimulating upregulation of netrin-1, to explore intracellular signal transduction mechanism of electroacupuncture activating UNC5B as inhibitory receptor of netrin-1 by advanced technologies such as DWI, DTI, neural tracing, gene intervenation. This project will help to elucidate the possible mechanisms of electroacupuncture treatment on degenerative disc diseases.

腰椎间盘退变性疾病临床多发，且易复发，因此，对腰椎间盘退变的防治研究，一直是国际相关研究领域关注的焦点。如何延缓腰椎间盘退变后有髓神经纤维内向生长，改善盘源性疼痛，具有十分重要的现实意义。我们前期采用腰椎间盘退变模型，从几种髓鞘相关的轴突导向因子中，筛选出支配退变椎间盘相对应的DRG Netrin-1表达上调与电针抑制椎间盘有髓神经纤维内向生长密切相关，为研究电针治疗腰椎间盘退变性疾病的机制提供了新的契机。本项目采用DWI和DTI、神经示踪、基因干预等先进技术，拟阐明Netrin-1在电针抑制椎间盘有髓神经纤维内向生长中的关键作用，研究电针上调Netrin-1表达的阿片肽机制，并探讨电针激活Netrin-1抑制性受体UNC5B发挥效应的细胞内信号转导机制。本项目研究有助于阐明电针治疗椎间盘退变性疾病的可能机制。

腰椎间盘退变性疾病是临床多发病，因此，对腰椎间盘退变的防治研究，一直是国际相关研究领域关注的焦点。本研究通过建立腰椎间盘退变模型，结合磁共振、免疫荧光组织化学、分子生物学、慢病毒载体构建和病毒包装等关键技术，首先证实电针对退变腰椎间盘模型兔DRG Netrin-1表达的影响，继而研究Netrin-1在电针抑制退变椎间盘有髓纤维内向生长中所起的关键作用，最后探讨电针通过Netrin-1受体UNC5B抑制退变椎间盘有髓神经纤维内向生长的信号转导通路。研究结果发现：电针能减少退变椎间盘神经炎症因子SP和NF200的表达，改善椎间盘组织学评分；电针能上调DRG Netrin-1的蛋白表达，抑制退变椎间盘神经纤维内向生长；上调DRG Netrin-1表达能模拟电针的作用，下调DRG Netrin-1表达可以显著翻转电针抑制退变椎间盘有髓神经纤维内向生长的现象；电针能上调退变椎间盘脊髓背角阿片肽的表达，阿片肽物质含量与DRG Netrin-1表达的有明显的相关性，阿片肽受体拮抗剂能翻转电针的作用；电针能上调DRG Netrin-1受体UNC5B的表达、下调受体DCC表达的，电针能上调DRG cGMP浓度、下调cAMP浓度，椎间盘退变诱导DRG中Ca2+浓度上调，电针能下调Ca2+浓度。结论：电针可能通过内源性阿片肽上调DRG表达轴突导向因子Netrin-1，激活其抑制性受体UNC5B，依赖cGMP的信号转导通路，抑制退变腰椎间盘有髓神经纤维内向生长，缓解盘源性疼痛。