Hansen Tove, Smolders Lucas A, Tryfonidou Marianna A, Meij Björn P, Vernooij Johannes C M, Bergknut Niklas, Grinwis Guy C M
1 Department of Clinical Science, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, Uppsala, Sweden.
2 Clinic for Small Animal Surgery, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
Vet Pathol. 2017 Nov;54(6):945-952. doi: 10.1177/0300985817726834. Epub 2017 Aug 29.
Since the seminal work by Hans-Jörgen Hansen in 1952, it has been assumed that intervertebral disc (IVD) degeneration in chondrodystrophic (CD) dogs involves chondroid metaplasia of the nucleus pulposus, whereas in nonchondrodystrophic (NCD) dogs, fibrous metaplasia occurs. However, more recent studies suggest that IVD degeneration in NCD and CD dogs is more similar than originally thought. Therefore, the aim of this study was to compare the histopathology of IVD degeneration in CD and NCD dogs. IVDs with various grades of degeneration (Thompson grade I-III, n = 7 per grade) from both CD and NCD dogs were used (14 CD and 18 NCD dogs, 42 IVDs in total). Sections were scored according to a histological scoring scheme for canine IVD degeneration, including evaluation of the presence of fibrocyte-like cells in the nucleus pulposus. In CD dogs, the macroscopically non-degenerated nucleus pulposus contained mainly chondrocyte-like cells, whereas the non-degenerated nucleus pulposus of NCD dogs mainly contained notochordal cells. The histopathological changes in degenerated discs were similar in CD and NCD dogs and resembled chondroid metaplasia. Fibrocytes were not seen in the nucleus pulposus, indicating that fibrous degeneration of the IVD was not present in any of the evaluated grades of degeneration. In conclusion, intervertebral disc degeneration was characterized by chondroid metaplasia of the nucleus pulposus in both NCD and CD dogs. These results revoke the generally accepted concept that NCD and CD dogs suffer from a different type of IVD degeneration, in veterinary literature often referred to as chondroid or fibroid degeneration, and we suggest that chondroid metaplasia should be used to describe the tissue changes in the IVD in both breed types.
自1952年汉斯 - 约尔根·汉森的开创性工作以来，人们一直认为软骨发育不良（CD）犬的椎间盘（IVD）退变涉及髓核的软骨样化生，而非软骨发育不良（NCD）犬则发生纤维化生。然而，最近的研究表明，NCD和CD犬的IVD退变比最初认为的更为相似。因此，本研究的目的是比较CD和NCD犬IVD退变的组织病理学。使用了来自CD和NCD犬的不同退变等级（汤普森I - III级，每个等级n = 7）的IVD（14只CD犬和18只NCD犬，共42个IVD）。根据犬IVD退变的组织学评分方案对切片进行评分，包括评估髓核中纤维样细胞的存在情况。在CD犬中，宏观上未退变的髓核主要含有软骨样细胞，而NCD犬未退变的髓核主要含有脊索细胞。CD和NCD犬退变椎间盘的组织病理学变化相似，类似于软骨样化生。在髓核中未见到纤维细胞，表明在所评估的任何退变等级中均不存在IVD的纤维退变。总之，NCD和CD犬的椎间盘退变均以髓核的软骨样化生为特征。这些结果推翻了兽医文献中普遍接受的概念，即NCD和CD犬患有不同类型的IVD退变，通常称为软骨样或纤维样退变，并且我们建议应使用软骨样化生来描述两种品种类型IVD中的组织变化。
