title: Evaluation of intervertebral disc regeneration with implantation of bone marrow mesenchymal stem cells (BMSCs) using quantitative T2 mapping: a study in rabbits.
abstract: OBJECTIVE
  The aim of the study was to investigate the curative effects of transplantation of bone marrow mesenchymal stem cells (BMSCs) on intervertebral disc regeneration and to investigate the feasibility of the quantitative T2 mapping method for evaluating repair of the nucleus pulposus after implantation of BMSCs.
  
  
  METHODS
  Forty-eight New Zealand white rabbits were used to establish the lumber disc degenerative model by stabbing the annulus fibrosus and then randomly divided into four groups, i.e. two weeks afterwards, BMSCs or phosphate-buffered saline (PBS) were transplanted into degenerative discs (BMSCs group and PBS group), while the operated rabbits without implantation of BMSCs or PBS served as the sham group and the rabbits without operation were used as the control group. At weeks two, six and ten after operation, the T2 values and disc height indices (DHI) were calculated by magnetic resonance imaging (MRI 3.0 T), and the gene expressions of type II collagen (COL2) and aggrecan (ACAN) in degenerative discs were evaluated by real-time reverse transcription polymerase chain reaction (RT-PCR). T2 values for the nucleus pulposus were correlated with ACAN or COL2 expression by regression analysis.
  
  
  RESULTS
  Cell clusters, disorganised fibres, interlamellar glycosaminoglycan (GAG) matrix and vascularisation were observed in lumber degenerative discs. BMSCs could be found to survive in intervertebral discs and differentiate into nucleus pulposus-like cells expressing COL2 and ACAN. The gene expression of COL2 and ACAN increased during ten weeks after transplantation as well as the T2 signal intensity and T2 value. The DHI in the BMSCs group decreased more slowly than that in PBS and sham groups. The T2 value correlated significantly with the gene expression of ACAN and COL2 in the nucleus pulposus.
  
  
  CONCLUSIONS
  Transplantation of BMSCs was able to promote the regeneration of degenerative discs. Quantitative and non-invasive T2 mapping could be used to evaluate the regeneration of the nucleus pulposus with good sensitivity.
authors.affiliation: Department of Orthopedics, Zhong Da Hospital, Southeast University, Nanjing, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Cai
authors.forename: Xiao-Tao
authors.initials: XT
authors.lastname: Wu
authors.forename: Xin-Hui
authors.initials: XH
authors.lastname: Xie
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.forename: Xin
authors.initials: X
authors.lastname: Hong
authors.forename: Su-Yang
authors.initials: SY
authors.lastname: Zhuang
authors.forename: Lei
authors.initials: L
authors.lastname: Zhu
authors.forename: Yun-Feng
authors.initials: YF
authors.lastname: Rui
authors.forename: Rui
authors.initials: R
authors.lastname: Shi
mesh_terms: D053674:Aggrecans / Q000378:metabolism; D000818:Animals; D016026:Bone Marrow Transplantation / Q000379:methods*; D024043:Collagen Type II / Q000378:metabolism; D004195:Disease Models, Animal; D005240:Feasibility Studies; D007403:Intervertebral Disc / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D055959:Intervertebral Disc Degeneration / Q000601:surgery*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D045164:Mesenchymal Stem Cell Transplantation / Q000379:methods*; D011817:Rabbits; D060888:Real-Time Polymerase Chain Reaction; D012038:Regeneration
chemical_list: D053674:Aggrecans; D024043:Collagen Type II