Influence of in vitro maturation of engineered cartilage on the outcome of osteochondral repair in a goat model

Eur Cell Mater. 2012 Apr 5;23:222-36. doi: 10.22203/ecm.v023a17.

Abstract

This study was designed to determine if the maturation stage of engineered cartilage implanted in a goat model of cartilage injury influences the repair outcome. Goat engineered cartilage was generated from autologous chondrocytes cultured in hyaluronic acid scaffolds using 2 d, 2 weeks or 6 weeks of pre-culture and implanted above hydroxyapatite/hyaluronic acid sponges into osteochondral defects. Control defects were left untreated or treated with cell-free scaffolds. The quality of repair tissues was assessed 8 weeks or 8 months post implantation by histological staining, modified O'Driscoll scoring and biochemical analyses. Increasing pre-culture time resulted in progressive maturation of the grafts in vitro. After 8 weeks in vivo, the quality of the repair was not improved by any treatment. After 8 months, O'Driscoll histology scores indicated poor cartilage architecture for untreated (29.7 ± 1.6) and cell-free treated groups (24.3 ± 5.8). The histology score was improved when cellular grafts were implanted, with best scores observed for grafts pre-cultured for 2 weeks (16.3 ± 5.8). As compared to shorter pre-culture times, grafts cultured for 6 weeks (histology score: 22.3 ± 6.4) displayed highest type II/I collagen ratios but also inferior architecture of the surface and within the defect, as well as lower integration with native cartilage. Thus, pre-culture of engineered cartilage for 2 weeks achieved a suitable compromise between tissue maturity and structural/integrative properties of the repair tissue. The data demonstrate that the stage of development of engineered cartilage is an important parameter to be considered in designing cartilage repair strategies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cartilage Diseases / metabolism
  • Cartilage Diseases / pathology*
  • Cartilage Diseases / surgery
  • Cartilage, Articular / cytology*
  • Cartilage, Articular / growth & development
  • Cartilage, Articular / metabolism
  • Cells, Cultured
  • Chondrocytes / cytology*
  • Chondrocytes / metabolism
  • Chondrocytes / transplantation
  • Collagen Type I / metabolism
  • Collagen Type II / metabolism
  • Durapatite / chemistry
  • Female
  • Goats
  • Hyaluronic Acid / chemistry
  • Time Factors
  • Tissue Engineering / methods*
  • Tissue Scaffolds / chemistry
  • Tissue Transplantation / methods
  • Transplantation, Autologous
  • Wound Healing

Substances

  • Collagen Type I
  • Collagen Type II
  • Hyaluronic Acid
  • Durapatite