Monchaux Marie, Forterre Simone, Spreng David, Karol Agnieszka, Forterre Franck, Wuertz-Kozak Karin
Vetsuisse Faculty, Department of Clinical Veterinary Science, University of Bern, Bern, Switzerland.
Competence Center of Applied Biotechnology and Molecular Medicine (CABMM), University of Zurich, Zurich, Switzerland.
Front Immunol. 2017 Dec 4;8:1681. doi: 10.3389/fimmu.2017.01681. eCollection 2017.
Intervertebral disc herniation (IVDH) is an important pathology in humans and also in dogs. While the molecular disease mechanisms are well investigated in humans, little is known about the inflammatory mediators in naturally occurring canine IVDH. The objective of this study was to investigate whether the involved proinflammatory cytokines in human IVDH are also key cytokines in canine IVDH and thus to elucidate the suitability of the dog as a model for human trials. 59 samples from 25 dogs with surgically confirmed thoracolumbar IVDH were collected and classified in three subgroups: herniated (H), affected non-herniated (NH) disc, and adjacent non-affected (NA) disc. Discs from 11 healthy dogs acted as controls (C). Samples were analyzed for IL-1, IL-6, IL-8, and TNF-α expression (qPCR/ELISA) as well as cell infiltration and activation of the MAP kinase pathways (immunohistochemistry). Gene and protein expression of all key cytokines could be detected in IVDH affected dogs. Canine IVDH was significantly associated with a higher gene expression of IL-6 (H > C, NH > C) and TNF-α (H > C, NH > C, NA > C) and a significant down-regulation of IL-1β (H < C). Dogs with spontaneous pain had significantly higher IL-6 mRNA compared to those with pain arising only upon palpation. An inter-donor comparison (H and HN relative to NA) revealed a significant increase of IL-6 gene expression (H > NA, NH > NA). IL-8 (H > C, NA > C) and TNF-α (NH > C) protein levels were significantly increased in diseased dogs while inversely, IL-6 protein levels were significantly higher in patients with better clinical outcome. Aside from resident IVD cells, mostly monocytes and macrophages were found in extruded material, with concomitant activation of extracellular signal-regulated kinase p38 in the majority of samples. Dogs with spontaneous IVDH might provide a useful model for human disc diseases. Although the expression of key cytokines found in human IVDH was also demonstrated in canine tissue, the inflammatory mechanisms accompanying canine IVDH diverges partially from humans, which will require further investigations in the future. In dogs, IL-6 seems to play an important pathological role and may represent a new potential therapeutic target for canine patients.
椎间盘突出症（IVDH）在人类和犬类中都是一种重要的病理状况。虽然人类椎间盘突出症的分子发病机制已得到充分研究，但对于自然发生的犬类椎间盘突出症中的炎症介质却知之甚少。本研究的目的是调查人类椎间盘突出症中涉及的促炎细胞因子是否也是犬类椎间盘突出症的关键细胞因子，从而阐明犬作为人类试验模型的适用性。收集了25只经手术确诊为胸腰椎椎间盘突出症的犬的59个样本，并将其分为三个亚组：突出组（H）、受影响的非突出组（NH）椎间盘和相邻未受影响组（NA）椎间盘。11只健康犬的椎间盘作为对照组（C）。对样本进行了白细胞介素-1（IL-1）、白细胞介素-6（IL-6）、白细胞介素-8（IL-8）和肿瘤坏死因子-α（TNF-α）表达分析（定量聚合酶链反应/酶联免疫吸附测定）以及细胞浸润和丝裂原活化蛋白激酶途径激活情况分析（免疫组织化学）。在患有椎间盘突出症的犬中均可检测到所有关键细胞因子的基因和蛋白表达。犬类椎间盘突出症与IL-6（H＞C，NH＞C）和TNF-α（H＞C，NH＞C，NA＞C）的基因表达升高以及IL-1β（H＜C）的显著下调显著相关。与仅在触诊时出现疼痛的犬相比，自发疼痛的犬IL-6信使核糖核酸水平显著更高。供体间比较（H和HN相对于NA）显示IL-6基因表达显著增加（H＞NA，NH＞NA）。患病犬中IL-8（H＞C，NA＞C）和TNF-α（NH＞C）蛋白水平显著升高，相反，临床结局较好的患者中IL-6蛋白水平显著更高。除了椎间盘固有细胞外，在挤出物中主要发现单核细胞和巨噬细胞，大多数样本中细胞外信号调节激酶p38同时被激活。自发性椎间盘突出症的犬可能为人类椎间盘疾病提供有用的模型。虽然在人类椎间盘突出症中发现的关键细胞因子的表达在犬类组织中也得到了证实，但犬类椎间盘突出症伴随的炎症机制与人类部分不同，这在未来需要进一步研究。在犬类中，IL-6似乎起着重要的病理作用，可能代表犬类患者一个新的潜在治疗靶点。
