痤疮丙酸杆菌（P.acnes）血源性感染进而诱导／加速椎间盘退变的机制研究

Recent studies suggested Propionibacterium acnes (P.acnes) infection could lead to some clinical symptoms through inducing degeneration of intervertebral discs. However, there is few evidence to explain the source, the planting of P.acnes and the degeneration mechanism it induces.. Based on previous study, we plan to explore the correlation between P.acnes and the number of micro-vessel, the content of facilitating vascularization factors in the clinical discs tissues and utilize the model of disc vascularization which has P.acnes bacteremia to verify the hypothesis of “The P.acnes Blood-borne infection”. Furthermore, we analyze the correlation between P.acnes and the content of lactic acid by Liquid Chromatogram, and use P.acnes continuous incubation, co-culture of P.acnes and nucleus pulposus cells in vivo and vitro to test the theory that the acid micro-environment of degenerative disc is benefit for the P.acnes planting and proliferation. At last, we utilize the clinical date, experiments in vivo and vitro and apoptosis pathway-associated inhibitors and activators to verify that P.acnes can induce nucleus pulposus apoptosis through activating the intrinsic and extrinsic pathways of apoptosis, and then leads to discs degeneration. . Overall, this project will thoroughly investigates the pathway of P.acnes infection and the mechanism of its specific planting in discs and degeneration it induces, which may provide new ideas for understanding and treating degenerative disc diseases.

近十余年来发现，痤疮丙酸杆菌（P.acnes）感染椎间盘可诱导其退变，进而引发临床症状。但有关P.acnes来源、定植及其导致椎间盘退变机制的研究仍十分匮乏。因此，本课题拟探究临床椎间盘标本中微血管及血管形成因子含量与P.acnes之间的相关性，并采用P.acnes菌血症的椎间盘新生血管模型验证“P.acnes血源性感染”假说；基于退变椎间盘酸性微环境利于P.acnes定植及繁殖的认识，利用液相色谱比较分析临床标本中乳酸水平与P.acnes含量的相关性，并通过P.acnes连续孵化技术、体内／外共培养技术进一步验证。此外，采用临床数据、体内外试验及凋亡通路抑制剂／激动剂来验证P.acnes激活髓核细胞凋亡通路、诱导凋亡，从而加速椎间盘退变的发生机制。该项目完整地阐述了P.acnes的感染途径、特异性定植椎间盘机理及其导致退变的机制，有望为理解和治疗椎间盘退行性疾病提供一个全新的体系。

痤疮丙酸杆菌被认为是诱导椎间盘退行性改变和盘源性腰痛的最新病因，但其病理和病理生理机制的研究仍十分匮乏。在我们前期工作中，我们采用严格的对照排除污染可能并利用16Sr DNA PCR检测、HE染色及改良Brown-Brenn染色等多种方法，检测出退变椎间盘组织内痤疮丙酸杆菌的阳性感染率约为21.05%，首次证明了该菌在国人腰椎间盘组织内的潜伏存在。在此基础上，本研究中我们采用临床标本充分论证了痤疮丙酸杆菌感染与椎间盘退变存在的流行病学关联性；采用动物模型模拟了痤疮丙酸杆菌感染后如何诱导椎间盘退变的过程，从Koch法则的角度充分论证了这一病因-病理学联系；论证了痤疮丙酸杆菌椎间盘感染后通过TLR-2/JNK/线粒体途径导致髓核细胞凋亡进而诱导椎间盘退变的机制，并论证了自噬促进痤疮丙酸杆菌诱导的细胞凋亡而进一步加重椎间盘退变；论证了痤疮丙酸杆菌椎间盘感染后通过TLR2-NF-κB/JNK或ROS通路诱导髓核细胞NGF的分泌进而诱导/加重盘源性腰痛，阐述了痤疮丙酸杆菌导致盘源性腰痛的病理生理机制。本项目系统、完整地阐述了痤疮丙酸杆菌在椎间盘疾病中的病理和病理生理机制，建立了较为完善的痤疮丙酸杆菌导致椎间盘退变的理论体系，为后期探索痤疮丙酸杆菌导致退变机制中的潜在治疗靶点及椎间盘退变性疾病转化医学的靶向治疗提供坚实的理论依据。