title: Mesenchymal stem cells in rabbit meniscus and bone marrow exhibit a similar feature but a heterogeneous multi-differentiation potential: superiority of meniscus as a cell source for meniscus repair.
abstract: BACKGROUND
  The restoration of damaged meniscus has always been a challenge due to its limited healing capacity. Recently, bone marrow-derived mesenchymal stem cells (BMSCs) provide a promising alternative to repair meniscal defects. However, BMSCs are not ideal chondroprogenitor cells for meniscus repair because they have a high propensity for cartilage hypertrophy and bone formation. Our hypothesis is that mesenchymal stem cells (MSCs) reside in meniscus maintain specific traits distinct from others which may be more conducive to meniscus regeneration.
  
  
  METHODS
  MSCs were isolated from bone marrow and menisci of the rabbits. The similarities and differences between BMSCs and MMSCs were investigated in vitro by a cell culture model, ex vivo by a rabbit meniscus defect model and in vivo by a nude rat implantation model using histochemistry, immunocytochemistry, qRT-PCR and western blotting.
  
  
  RESULTS
  Our data showed that two types of MSCs have universal stem cell characteristics including clonogenicity, multi-potency and self-renewal capacity. They both express stem cell markers including SSEA-4, Nanog, nucleostemin, strol-1, CD44 and CD90. However, MMSCs differed from BMSCs. MMSC colonies were much smaller and grew more slowly than BMSC colonies. Moreover, fewer MMSCs expressed CD34 than BMSCs. Finally, MMSCs always appeared a pronounced tendency to chondrogenic differentiation while BMSCs exhibited significantly greater osteogenic potential, whatever in vitro and in vivo.
  
  
  CONCLUSIONS
  This study shows the similarities and differences between MMSCs and BMSCs for the first time. MMSCs are a promising source of mesenchymal stem cells in repairing meniscus defect.
authors.affiliation: Department of Ophthalmology, The 3rd Affiliated Hospital of Nanjing University of Traditional Chinese Medicine, 1 Jinling Road, Nanjing, Jiangsu, 210001, China. dingzhe75@163.com.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Ding
authors.affiliation: Department of Orthopaedic Surgery, Nanjing First Hospital, Nanjing Medical University, 68 Changle Road, Nanjing, Jiangsu, 210006, China. riversh922@hotmail.com.
authors.forename: He
authors.initials: H
authors.lastname: Huang
mesh_terms: D000818:Animals; D018952:Antigens, CD34 / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D001854:Bone Marrow Cells / Q000166:cytology* / Q000502:physiology; D001861:Bone Regeneration / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology*; D002478:Cells, Cultured; D020219:Chondrogenesis / Q000502:physiology; D005260:Female; D066298:In Vitro Techniques; D007596:Joints / Q000293:injuries*; D008592:Menisci, Tibial / Q000166:cytology* / Q000502:physiology; D045164:Mesenchymal Stem Cell Transplantation / Q000379:methods*; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000502:physiology; D023421:Models, Animal; D039902:Multipotent Stem Cells / Q000166:cytology* / Q000502:physiology; D011817:Rabbits; D051381:Rats; D011923:Rats, Nude; D014945:Wound Healing / Q000502:physiology
chemical_list: D018952:Antigens, CD34; D015415:Biomarkers