title: Comparison between loose fragment chondrocytes and condyle fibrochondrocytes in cellular proliferation and redifferentiation.
abstract: BACKGROUND
  Loose fragments in spontaneous osteonecrosis of the knee (SONK) are usually removed by surgical treatment. However, the healing potential of osteonecrotic loose fragments and their clinical availability, for example as a cell source for cartilage repair and tissue engineering, have not been investigated. The objective of this study was to evaluate the cellular proliferation and redifferentiation ability of loose fragment chondrocytes for the treatment of SONK.
  
  
  METHODS
  Cells were obtained from the remaining cartilage of chondral loose fragments or fibrocartilaginous tissue under the affected femoral condyle in SONK. The proliferation activity of loose fragment-derived chondrocytes and condyle-derived fibrochondrocytes was evaluated. In-vitro differentiation ability was assessed by PCR and histological analysis.
  
  
  RESULTS
  The deposition of proteoglycans and type II collagen were maintained in loose fragments. However, loose fragment-derived chondrocytes had lower proliferating activity than condyle-derived fibrochondrocytes. Chondrogenic redifferentiation ability was lower in loose fragment chondrocytes than in condyle fibrochondrocytes. Differentiation towards adipogenic and osteogenic lineages was not observed in loose fragment chondrocytes. On the other hand, lipid vacuoles were detected in fibrochondrocytes after adipogenic treatment.
  
  
  CONCLUSIONS
  This study demonstrated that loose fragment-derived chondrocytes in SONK had lower potential than fibrochondrocytes in cellular proliferation and redifferentiation. Our experimental results suggest that osteonecrotic loose fragments might have restricted cellular properties in the healing of SONK-related osteochondral defects.
authors: Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, 2-5-1 Shikatacho, Kitaku, Okayama, 700-8558, Japan.
authors: Naoki
authors: N
authors: Takata
authors: Takayuki
authors: T
authors: Furumatsu
authors: Nobuhiro
authors: N
authors: Abe
authors: Keiji
authors: K
authors: Naruse
authors: Toshifumi
authors: T
authors: Ozaki
mesh_terms: D000368:Aged; D002357:Cartilage Diseases / Q000628:therapy*; D002454:Cell Differentiation / Q000502:physiology*; D049109:Cell Proliferation; D019902:Chondrocytes / Q000502:physiology*; D024043:Collagen Type II / Q000378:metabolism; D024061:Collagen Type III / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010020:Osteonecrosis / Q000628:therapy*; D060888:Real-Time Polymerase Chain Reaction; D023822:Tissue Engineering; D014945:Wound Healing
chemical_list: C499177:COL2A1 protein, human; C439971:COL3A1 protein, human; D024043:Collagen Type II; D024061:Collagen Type III