title: Potential of exogenous cartilage proteoglycan as a new material for cartilage regeneration.
abstract: BACKGROUND
  Although proteoglycan (PG) is one of the major components of cartilage matrices, its biological function is not fully elucidated.
  
  
  METHODS
  The objectives of this study were to investigate the proliferation and differentiation of chondrocytes embedded in atelocollagen gel with exogenous cartilage PG (PG-atelocollagen gel) in vitro, and also to evaluate the repair of cartilage defects by PG-atelocollagen gel in vivo. In the in vitro study, rabbit chondrocytes were cultured in the PG-atelocollagen gel. Cell proliferation and mRNA expression levels were measured, and gels were histologically evaluated. In the in vivo study, cultured PG-atelocollagen gel containing chondrocytes were transplanted into full-thickness articular cartilage defects in rabbit knees, and evaluated macroscopically and histologically.
  
  
  RESULTS
  For the in vitro study, chondrocyte proliferation in 5.0 mg/ml PG-atelocollagen gel was enhanced, and the gene expression of Col2a1 and Aggrecan were decreased. In contrast, chondrocyte proliferation in 0.1 and 1.0 mg/ml PG-atelocollagen gel was not enhanced. The gene expression of Aggrecan in 0.1 and 1.0 mg/ml PG-atelocollagen gel was increased. For the in vivo study, the histological average total score of the 0.1 mg/ml PG-atelocollagen gel was significantly better than that of the group without PG.
  
  
  CONCLUSIONS
  Although the appropriate concentration of PG has not been defined, this study suggests the efficacy of PG for cartilage repair.
authors.affiliation: Department of Orthopaedic Surgery, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki 036-8562, Japan. ortho_ohshika@yahoo.co.jp
authors.forename: Shusa
authors.initials: S
authors.lastname: Ohshika
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Ishibashi
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kon
authors.forename: Tomomi
authors.initials: T
authors.lastname: Kusumi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kijima
authors.forename: Satoshi
authors.initials: S
authors.lastname: Toh
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000187:drug effects* / Q000293:injuries / Q000502:physiology; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology / Q000187:drug effects / Q000637:transplantation; D020219:Chondrogenesis / Q000187:drug effects*; D003094:Collagen / Q000494:pharmacology*; D004337:Drug Carriers / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects; D012333:RNA, Messenger / Q000378:metabolism; D011817:Rabbits; D012038:Regeneration / Q000187:drug effects* / Q000502:physiology
chemical_list: D004337:Drug Carriers; D012333:RNA, Messenger; C059821:atelocollagen; D003094:Collagen