title: Fibroblast growth factor-2 promotes the repair of partial thickness defects of articular cartilage in immature rabbits but not in mature rabbits.
abstract: OBJECTIVE
  To investigate cartilage response to fibroblast growth factor-2 (FGF-2) with increasing age in vivo, we examined the effect of FGF-2 on partial thickness defects of immature and mature rabbits.
  
  
  METHODS
  Sixty-nine Japanese white rabbits (34 immature rabbits, 35 mature rabbits) were examined. We made experimental partial thickness defects in articular cartilage of the knees. Then, we injected FGF-2 into the knees eight times, immediately after surgery and every 2 days for 2 weeks. A single dose of FGF-2 was 10 ng/0.1 ml or 100 ng/0.1 ml. In the control group, 0.1 ml saline was injected on the same time schedule. The rabbits were sacrificed at intervals following surgery that ranged from 2 to 48 weeks. The specimens were stained with toluidine blue and examined microscopically. We used a modified semiquantitative scale for evaluating the histological appearance of repair.
  
  
  RESULTS
  In immature rabbits, the cartilage repair in the FGF-2 (100 ng)-treated group was significantly better than that of the other groups. The defects were almost completely repaired with chondrocytes that showed a round to polygonal morphology, and large amounts of extracellular matrix with intense metachromatic staining. In mature rabbits, however, there was apparently no effect from FGF-2 in either group.
  
  
  CONCLUSIONS
  Application of FGF-2 facilitated cartilage repair in partial thickness defects in immature rabbits, but not in mature ones.
authors.affiliation: Department of Orthopaedic Surgery, Osaka-Minami National Hospital, Kawachinagano, Japan. yamatetsu@ommc-hp.jp
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Wakitani
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Imoto
authors.forename: Takako
authors.initials: T
authors.lastname: Hattori
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nakaya
authors.forename: Masanobu
authors.initials: M
authors.lastname: Saito
authors.forename: Kazuo
authors.initials: K
authors.lastname: Yonenobu
mesh_terms: D000375:Aging / Q000473:pathology* / Q000502:physiology; D000818:Animals; D002358:Cartilage, Articular / Q000187:drug effects / Q000293:injuries* / Q000473:pathology; D019902:Chondrocytes / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D016222:Fibroblast Growth Factor 2 / Q000627:therapeutic use*; D007270:Injections, Intra-Articular; D008297:Male; D011817:Rabbits; D011994:Recombinant Proteins / Q000627:therapeutic use; D014945:Wound Healing / Q000187:drug effects* / Q000502:physiology
chemical_list: D011994:Recombinant Proteins; D016222:Fibroblast Growth Factor 2