title: Repair of osteochondral defects with recombinant human type II collagen gel and autologous chondrocytes in rabbit.
abstract: OBJECTIVE
  Recombinant human type II collagen (rhCII) gels combined with autologous chondrocytes were tested as a scaffold for cartilage repair in rabbits in vivo.
  
  
  METHODS
  Autologous chondrocytes were harvested, expanded and combined with rhCII-gel and further pre-cultivated for 2 weeks prior to transplantation into a 4 mm diameter lesion created into the rabbit's femoral trochlea (n = 8). Rabbits with similar untreated lesions (n = 7) served as a control group.
  
  
  RESULTS
  Six months after the transplantation the repair tissue in both groups filled the lesion site, but in the rhCII-repair the filling was more complete. Both repair groups also had high proteoglycan and type II collagen contents, except in the fibrous superficial layer. However, the integration to the adjacent cartilage was incomplete. The O'Driscoll grading showed no significant differences between the rhCII-repair and spontaneous repair, both representing lower quality than intact cartilage. In the repair tissues the collagen fibers were abnormally organized and oriented. No dramatic changes were detected in the subchondral bone structure. The repair cartilage was mechanically softer than the intact tissue. Spontaneously repaired tissue showed lower values of equilibrium and dynamic modulus than the rhCII-repair. However, the differences in the mechanical properties between all three groups were insignificant.
  
  
  CONCLUSIONS
  When rhCII was used to repair cartilage defects, the repair quality was histologically incomplete, but still the rhCII-repairs showed moderate mechanical characteristics and a slight improvement over those in spontaneous repair. Therefore, further studies using rhCII for cartilage repair with emphasis on improving integration and surface protection are required.
authors.affiliation: Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland. hertta.pulkkinen@uef.fi
authors.forename: H J
authors.initials: HJ
authors.lastname: Pulkkinen
authors.forename: V
authors.initials: V
authors.lastname: Tiitu
authors.forename: P
authors.initials: P
authors.lastname: Valonen
authors.forename: J S
authors.initials: JS
authors.lastname: Jurvelin
authors.forename: L
authors.initials: L
authors.lastname: Rieppo
authors.forename: J
authors.initials: J
authors.lastname: Töyräs
authors.forename: T S
authors.initials: TS
authors.lastname: Silvast
authors.forename: M J
authors.initials: MJ
authors.lastname: Lammi
authors.forename: I
authors.initials: I
authors.lastname: Kiviranta
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000000981:diagnostic imaging / Q000473:pathology*; D016022:Case-Control Studies; D019902:Chondrocytes / Q000637:transplantation*; D024043:Collagen Type II / Q000032:analysis / Q000627:therapeutic use*; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D005782:Gels; D006614:Hindlimb; D006801:Humans; D008859:Microscopy, Polarization; D011509:Proteoglycans / Q000032:analysis; D011817:Rabbits; D017550:Spectroscopy, Fourier Transform Infrared; D013264:Stifle; D013314:Stress, Mechanical; D054457:Tissue Scaffolds; D016896:Treatment Outcome; D014945:Wound Healing / Q000502:physiology*; D055114:X-Ray Microtomography
chemical_list: D024043:Collagen Type II; D005782:Gels; D011509:Proteoglycans