title: The dog as an animal model for intervertebral disc degeneration?
abstract: METHODS
  Prospective observational and analytic study.
  
  
  OBJECTIVE
  To investigate whether spontaneous intervertebral disc degeneration (IVDD) occurring in both chondrodystrophic (CD) and nonchondrodystrophic dogs (NCD) can be used as a valid translational model for human IVDD research.
  
  
  BACKGROUND
  Different animal models are used in IVDD research, but in most of these models IVDD is induced manually or chemically rather than occurring spontaneously.
  
  
  METHODS
  A total of 184 intervertebral discs (IVDs) from 19 dogs of different breeds were used. The extent of IVDD was evaluated by macroscopic grading, histopathology, glycosaminoglycan content, and matrix metalloproteinase 2 activity. Canine data were compared with human IVD data acquired in this study or from the literature.
  
  
  RESULTS
  Gross pathology of IVDD in both dog types (CD and NCD) and humans showed many similarities, but the cartilaginous endplates were significantly thicker and the subchondral cortices significantly thinner in humans than in dogs. Notochordal cells were still present in the IVDs of adult NCD but were not seen in the CD breeds or in humans. Signs of degeneration were seen in young dogs of CD breeds (<1 year of age), whereas this was only seen in older dogs of NCD breeds (5-7 years of age). The relative glycosaminoglycan content and metalloproteinase 2 activity in canine IVDD were similar to those in humans: metalloproteinase 2 activity increased and glycosaminoglycan content decreased with increasing severity of IVDD.
  
  
  CONCLUSIONS
  IVDD is similar in humans and dogs. Both CD and NCD breeds may therefore serve as models of spontaneous IVDD for human research. However, as with all animal models, it is important to recognize interspecies differences and, indeed, the intraspecies differences between CD and NCD breeds (early vs. late onset of IVDD, respectively) to develop an optimal canine model of human IVDD.
authors.affiliation: Department of Clinical Sciences of Companion Animals, Utrecht University, Utrecht, The Netherlands. n.bergknut@uu.nl
authors.forename: Niklas
authors.initials: N
authors.lastname: Bergknut
authors.forename: Joost P H J
authors.initials: JP
authors.lastname: Rutges
authors.forename: Hendrik-Jan C
authors.initials: HJ
authors.lastname: Kranenburg
authors.forename: Lucas A
authors.initials: LA
authors.lastname: Smolders
authors.forename: Ragnvi
authors.initials: R
authors.lastname: Hagman
authors.forename: Hendrik-Jan
authors.initials: HJ
authors.lastname: Smidt
authors.forename: Anne-Sofie
authors.initials: AS
authors.lastname: Lagerstedt
authors.forename: Louis C
authors.initials: LC
authors.lastname: Penning
authors.forename: George
authors.initials: G
authors.lastname: Voorhout
authors.forename: Herman A W
authors.initials: HA
authors.lastname: Hazewinkel
authors.forename: Guy C M
authors.initials: GC
authors.lastname: Grinwis
authors.forename: Laura B
authors.initials: LB
authors.lastname: Creemers
authors.forename: Björn P
authors.initials: BP
authors.lastname: Meij
authors.forename: Wouter J A
authors.initials: WJ
authors.lastname: Dhert
mesh_terms: D000375:Aging / Q000473:pathology; D000818:Animals; D004195:Disease Models, Animal; D004285:Dogs; D005260:Female; D051445:Fibrocartilage / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology*; D006801:Humans; D007403:Intervertebral Disc / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology*; D055959:Intervertebral Disc Degeneration / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology*; D008297:Male; D011446:Prospective Studies; D013045:Species Specificity