title: An in vitro organ culturing system for intervertebral disc explants with vertebral endplates: a feasibility study with ovine caudal discs.
abstract: METHODS
  Whole ovine caudal intervertebral discs with vertebral endplates were cultured under uniaxial diurnal loading for 7 days.
  
  
  OBJECTIVE
  To establish and characterize an organ culture system for intervertebral discs, in which disc cells may be "maintained" in their native three-dimensional environment under load.
  
  
  BACKGROUND
  In vitro culturing of entire discs with preserved biologic and structural integrity would be a useful model to study the effects of nutrition and mechanical loading.
  
  
  METHODS
  To maintain endplate permeability, sheep were systemically anticoagulated before death and their caudal vasculature was evacuated with saline postmortem. The first 4 caudal discs were explanted with their adjacent endplates and cultured in bioreactors under uniaxial diurnal loading (0.2 MPa for 8 hours and 0.8 MPa for 16 hours) for 4 or 7 days. Solute transport into the center of the disc was measured after 4 days of culture using a low molecular weight fluorescent marker. Cell viability, glycosaminoglycan synthesis rate, and gene expression profile were measured after 7 days of culture and compared with fresh tissue.
  
  
  RESULTS
  Fluorescent images showed that solutes could diffuse into the disc under both static and diurnal loading, but penetration through the endplate increased with diurnal loading. Cell viability and glycosaminoglycan synthesis rates remained unchanged after 7 days of culture. Expression of catabolic genes was significantly up-regulated, whereas anabolic genes tended to be down-regulated after 7 days.
  
  
  CONCLUSIONS
  With this novel preparation and culturing technique, endplate permeability could be maintained, which allowed culturing of intact disc explants with endplates for up to 7 days.
authors.affiliation: AO Research Institute, Davos, Switzerland.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Gantenbein
authors.forename: Thijs
authors.initials: T
authors.lastname: Grünhagen
authors.forename: Cynthia R
authors.initials: CR
authors.lastname: Lee
authors.forename: Corrinus C
authors.initials: CC
authors.lastname: van Donkelaar
authors.forename: Mauro
authors.initials: M
authors.lastname: Alini
authors.forename: Keita
authors.initials: K
authors.lastname: Ito
mesh_terms: D000818:Animals; D001692:Biological Transport; D019149:Bioreactors; D002470:Cell Survival; D002940:Circadian Rhythm; D015536:Down-Regulation; D005240:Feasibility Studies; D005456:Fluorescent Dyes / Q000493:pharmacokinetics; D015870:Gene Expression; D006025:Glycosaminoglycans / Q000096:biosynthesis; D007403:Intervertebral Disc / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D009924:Organ Culture Techniques; D010539:Permeability; D012756:Sheep; D013131:Spine / Q000378:metabolism / Q000502:physiology; D013997:Time Factors; D015854:Up-Regulation; D016474:Weight-Bearing
chemical_list: D005456:Fluorescent Dyes; D006025:Glycosaminoglycans