title: Comparison of animal discs used in disc research to human lumbar disc: axial compression mechanics and glycosaminoglycan content.
abstract: METHODS
  Experimental measurement and normalization of in vitro disc axial compression mechanics and glycosaminoglycan and water content for several animal species used in intervertebral disc research.
  
  
  OBJECTIVE
  To compare normalized axial mechanical properties and glycosaminoglycan and water content from other species to those of the human disc to aid in selection and interpretation of results in animal disc studies.
  
  
  BACKGROUND
  There is a lack of mechanical and biochemical comparative data from animal intervertebral discs with respect to the human disc.
  
  
  METHODS
  Intervertebral disc axial mechanical properties, glycosaminoglycan, and water content were evaluated for 9 disc types in 7 mammalian species: the calf, pig, baboon, sheep, rabbit, rat and mouse lumbar, and the cow and rat tail. Disc area and height were used for calculation of the normalized mechanical parameters. Glycosaminoglycan content was normalized by dry weight.
  
  
  RESULTS
  Many directly measured mechanical parameters varied by orders of magnitude. However, these parameters became comparable and often did not show significant differences after geometric normalization. Both glycosaminoglycan and water content revealed similarity across species.
  
  
  CONCLUSIONS
  Disc axial mechanics are very similar across animal species when normalizing by the geometric parameters of disc height and area. This suggests that the disc tissue material properties are largely conserved across animal species. These results provide a reference to compare disc axial mechanics and glycosaminoglycan and water composition of experimental animal models to the human lumbar disc, to aid in both selection and interpretation of experimental disc research.
authors.affiliation: McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA 19104-6081, USA.
authors.forename: Jesse C
authors.initials: JC
authors.lastname: Beckstein
authors.forename: Sounok
authors.initials: S
authors.lastname: Sen
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Schaer
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Vresilovic
authors.forename: Dawn M
authors.initials: DM
authors.lastname: Elliott
mesh_terms: D000328:Adult; D000818:Animals; D001696:Biomechanical Phenomena / Q000295:instrumentation / Q000379:methods; D002417:Cattle; D019245:Compressive Strength / Q000502:physiology; D005260:Female; D006025:Glycosaminoglycans / Q000032:analysis*; D006801:Humans; D007403:Intervertebral Disc / Q000737:chemistry / Q000502:physiology*; D008159:Lumbar Vertebrae / Q000737:chemistry / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008875:Middle Aged; D010215:Papio; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D012107:Research Design / Q000592:standards; D012756:Sheep; D013045:Species Specificity; D013552:Swine
chemical_list: D006025:Glycosaminoglycans