title: Intervention of rAAV-hTERT-Transducted Nucleus Pulposus Cells in Early Stage of Intervertebral Disc Degeneration: A Study in Canine Model.
abstract: OBJECTIVE
  To investigate the efficacy of recombinant adeno-associated virus (rAAV)-human telomerase reverse transcriptase (hTERT)-transducted nucleus pulposus cells (NPCs) in disc degeneration process in a canine disc degeneration model.
  
  
  METHODS
  The intervertebral disc degeneration of lumbar (L) 1-2, L3-4, and L5-6, from 12 female mongrels was prepared with the 20-gauge biopsy gun. Four weeks after animal model preparation, intervention experiment with rAAV-hTERT-transducted NPCs was conducted: group A, L1-2, serum-free medium with rAAV-hTERT modified NPCs; group B, L3-4, serum-free medium with NPCs; group C, L5-6, serum-free medium alone. Canines underwent digital radiography and magnetic resonance imaging 1 day before intervention, and 4, 8, and 12 weeks after intervention to evaluate the change of disc height and hydration status of interventional intervertebral discs. Twelve weeks after intervention, histological, biomechanical, and biochemical studies were carried out.
  
  
  RESULTS
  The rAAV-hTERT-transducted NPCs were constructed successfully. The mRNA level of hTERT from rAAV-hTERT-transfected NPCs increased obviously. There was no significant change of disc height index observed between groups and within groups. The relative grayscale index (RGI) was maintained 8 weeks after the intervention in group A, whereas in group B and group C, the RGI decreased significantly (p<0.05). No significant differences of the angle of lateral bending and extension-flexion bending were observed in group A compared with other groups (p>0.05). The morphology of disc structure was preserved in group A. In group B, the structure of inner annulus was broken down and the jelly-like nucleus pulposus (NP) tissue transmitted into the fibrocartilaginous tissue. In group C, the jelly-like NP tissue was completely replaced by fibrocartilaginous tissue. In the NP, the content of proteoglycan (PG) and collagen II was higher in group A than in group C (p<0.05). The content of PG was 13, 8.9, and 15.6 times higher than the content of collagen II in group A, group B, and group C, respectively.
  
  
  CONCLUSIONS
  In 12 weeks of observation, rAAV-hTERT-transducted NPCs could delay the degeneration process in the canine model which was superior than the capacity of NPCs in preserving structure integrity, content of extracellular matrix, and mechanical stability.
authors.affiliation: 1 Department of Orthopedic Surgery, Navy General Hospital , Beijing, People's Republic of China .|2 Department of Burn and Plastic Surgery, Navy General Hospital , Beijing, People's Republic of China .
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Shi
authors.affiliation: 1 Department of Orthopedic Surgery, Navy General Hospital , Beijing, People's Republic of China .
authors.forename: Tao
authors.initials: T
authors.lastname: Gu
authors.affiliation: 1 Department of Orthopedic Surgery, Navy General Hospital , Beijing, People's Republic of China .
authors.forename: Hongkui
authors.initials: H
authors.lastname: Xin
authors.affiliation: 1 Department of Orthopedic Surgery, Navy General Hospital , Beijing, People's Republic of China .
authors.forename: Jianhong
authors.initials: J
authors.lastname: Wu
authors.affiliation: 1 Department of Orthopedic Surgery, Navy General Hospital , Beijing, People's Republic of China .
authors.forename: Cheng
authors.initials: C
authors.lastname: Xu
authors.affiliation: 1 Department of Orthopedic Surgery, Navy General Hospital , Beijing, People's Republic of China .
authors.forename: Chao
authors.initials: C
authors.lastname: Zhang
authors.affiliation: 1 Department of Orthopedic Surgery, Navy General Hospital , Beijing, People's Republic of China .
authors.forename: Qing
authors.initials: Q
authors.lastname: He
authors.affiliation: 1 Department of Orthopedic Surgery, Navy General Hospital , Beijing, People's Republic of China .
authors.forename: Dike
authors.initials: D
authors.lastname: Ruan
mesh_terms: D000818:Animals; D000229:Dependovirus; D004195:Disease Models, Animal; D004285:Dogs; D005260:Female; D015316:Genetic Therapy; D006801:Humans; D007403:Intervertebral Disc / Q000201:enzymology* / Q000473:pathology; D055959:Intervertebral Disc Degeneration / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D019098:Telomerase / Q000096:biosynthesis / Q000235:genetics; D014161:Transduction, Genetic
chemical_list: C509186:TERT protein, human; D019098:Telomerase