Rabbit Articular Cartilage Defects Treated With Autologous Cultured Chondrocytes

TLDR

Adult New Zealand rabbits received autologous chondrocytes that were expanded in vitro and transplanted into 3‑mm patellar chondral defects, with healing evaluated at 8, 12, and 52 weeks by gross, light‑microscopic, and histological scoring. Transplantation of cultured chondrocytes markedly increased repair tissue volume and histologic quality compared with periosteal flaps or cell‑free scaffolds, with continued maturation toward hyaline cartilage over one year, although bonding to adjacent cartilage remained incomplete.

Abstract

Adult New Zealand rabbits were used to transplant autologously harvested and in vitro cultured chondrocytes into patellar chondral lesions that had been made previously and were 3 mm in diameter, extending down to the calcified zone. Healing of the defects was assessed by gross examination, light microscope, and histological-histochemical scoring at 8, 12, and 52 weeks. Chondrocyte transplantation significantly increased the amount of newly formed repair tissue compared to that found in control knees in which the lesion was solely covered by a periosteal flap. In another experiment, carbon fiber pads seeded with chondrocytes were used as scaffolds, and repair significantly increased at both 12 and 52 weeks compared to knees in which scaffolds without chondrocytes were implanted. The histologic quality scores of the repair tissue were significantly better in all knees in which defects were treated with chondrocytes compared to knees treated with periosteum alone and better at 52 weeks compared to knees in which defects were treated with carbon scaffolds seeded with chondrocytes. The repair tissue, however, tended to incomplete the bonding to adjacent cartilage. This study shows that isolated autologous articular chondrocytes that have been expanded for 2 weeks in vitro can stimulate the healing phase of chondral lesions. A gradual maturation of the hyalinelike repair with a more pronounced columnarization was noted as late as 1 year after surgery.