title: Establishment of intervertebral disc degeneration model induced by ischemic sub-endplate in rat tail.
abstract: BACKGROUND
  Microcirculatory dysfunction of the sub-endplate is considered to reduce nutrient supply to the intervertebral disc (IVD); however, direct interruption or destruction of blood vessels in the bone marrow of the vertebrae body adjacent to the endplate has not yet been described, especially with regard to the calcification and ossification of the cartilaginous endplate occurring during IVD degeneration.
  
  
  OBJECTIVE
  The purpose of the study was to evaluate the causal relationship between IVD degeneration and blocking of the main blood supply gateway through the endplate.
  
  
  METHODS
  The study describes a new IVD degeneration model induced by ischemic sub-endplate.
  
  
  METHODS
  A total of 40 Sprague-Dawley rats were included in the study group.
  
  
  METHODS
  To assess disc height, a radiograph was taken each month for 4 months. Changes in endplate, nucleus pulposus (NP), and annulus fibrosus (AF) were evaluated by histochemical and immunohistochemical staining to detect IVD degeneration.
  
  
  METHODS
  Injection of 30 μL absolute ethanol into the IVD of rat tail at Co7/Co8 was used to induce injury. Controls were injected with 30 μL of phosphate-buffered saline into the IVD at Co8/Co9.
  
  
  RESULTS
  In the ethanol-injected group, disc height gradually decreased and bone sclerosis developed in the endplate. In the NP, cell transformation occurred, changing from predominantly vacuolar cells to chondrogenic cells and eventually fibrocartilaginous cells, along with fibrosis of the NP. As degeneration progressed, the AF developed disordered morphology and rough lamellae, and eventually ruptures and fibrosis. The extent of degeneration increased gradually over time, while the wavy tidemark of the growth plate regressed, and eventually disappeared. Initially positive collagen type II staining gradually decreased on the ischemic side of the sub-endplate. Except at the 3-month time point, expression of collagen type II, aggrecan, and Sox-9 in NP decreased gradually as degeneration progressed, compared with the control group.
  
  
  CONCLUSIONS
  This model successfully reproduced IVD degeneration, which could be used for etiological studies on IVD degeneration and investigation of nutrient supply disturbance, and may provide a theoretical foundation for clinical intervention and therapy for IVD degeneration in the future.
authors: Department of Orthopaedic Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, China; Department of Spinal Disease Unit, Yue Yang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, 200437, China.
authors: Wei
authors: W
authors: Yuan
authors: Department of Orthopaedic Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, China.
authors: Wu
authors: W
authors: Che
authors: Department of Orthopaedic Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, China.
authors: Yun-Qi
authors: YQ
authors: Jiang
authors: Department of Orthopaedic Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, China.
authors: Feng-Lai
authors: FL
authors: Yuan
authors: Department of Orthopaedic Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, China.
authors: Hui-Ren
authors: HR
authors: Wang
authors: Department of Orthopaedic Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, China.
authors: Guo-Li
authors: GL
authors: Zheng
authors: Department of Orthopaedic Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, China. Electronic address: li.xilei@zs-hospital.sh.cn.
authors: Xi-Lei
authors: XL
authors: Li
authors: Department of Orthopaedic Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, China. Electronic address: dong.jian@zs-hospital.sh.cn.
authors: Jian
authors: J
authors: Dong
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D006801:Humans; D007403:Intervertebral Disc / Q000098:blood supply* / Q000473:pathology; D055959:Intervertebral Disc Degeneration / Q000209:etiology* / Q000503:physiopathology; D007511:Ischemia / Q000150:complications*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013623:Tail / Q000098:blood supply*
keywords: Absolute ethanol; Animal model; Endplate; Intervertebral disc degeneration; Rat tail