title: Spinal traction promotes molecular transportation in a simulated degenerative intervertebral disc model.
abstract: METHODS
  Biomechanical experiment using an in situ porcine model.
  
  
  OBJECTIVE
  To find the effect of traction treatment on annulus microstructure, molecular convection, and cell viability of degraded discs.
  
  
  BACKGROUND
  Spinal traction is a conservative treatment for disc disorders. The recognized biomechanical benefits include disc height recovery, foramen enlargement, and intradiscal pressure reduction. However, the influence of traction treatment on annulus microstructure, molecular transportation, and cell viability of degraded discs has not been fully investigated.
  
  
  METHODS
  A total of 48 thoracic discs were dissected from 8 porcine spines (140 kg, 6-month old) within 4 hours after killing them and then divided into 3 groups: intact, degraded without traction, and degraded with traction. Each disc was incubated in a whole-organ culture system and subjected to diurnal loadings for 7 days. Except for the intact group, discs were degraded with 0.5 mL of trypsin on day 1 and a 5-hour fatigue loading on day 2. From day 4 to day 6, half of the degraded discs received a 30-minute traction treatment per day (traction force: 20 kg; loading: unloading = 30 s: 10 s). By the end of the incubation, the discs were inspected for disc height loss, annulus microstructure, molecular (fluorescein sodium) intensity, and cell viability.
  
  
  RESULTS
  Collagen fibers were crimped and delaminated, whereas the pores were occluded in the annulus fibrosus of the degraded discs. Molecular transportation and cell viability of the discs decreased after matrix degradation. With traction treatment, straightened collagen fibers increased within the degraded annulus fibrosus, and the annulus pores were less occluded. Both molecular transportation and cell viability increased, but not to the intact level.
  
  
  CONCLUSIONS
  Traction treatment is effective in enhancing nutrition supply and promoting disc cell proliferation of the degraded discs.
  
  
  METHODS
  N/A.
authors: From the Institute of Biomedical Engineering, College of Medicine and College of Engineering, National Taiwan University, Taipei, Taiwan.
authors: Ya-Wen
authors: YW
authors: Kuo
authors: Yu-Chun
authors: YC
authors: Hsu
authors: I-Ting
authors: IT
authors: Chuang
authors: Pen-Hsiu Grace
authors: PH
authors: Chao
authors: Jaw-Lin
authors: JL
authors: Wang
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D002470:Cell Survival; D007403:Intervertebral Disc / Q000473:pathology / Q000601:surgery; D055959:Intervertebral Disc Degeneration / Q000473:pathology / Q000601:surgery*; D013552:Swine; D013904:Thoracic Vertebrae / Q000473:pathology / Q000601:surgery*; D014143:Traction; D016474:Weight-Bearing / Q000502:physiology