UC San Diego

Few studies have examined the response of whole or hemi joints to culture in a configuration where the cartilage tissue is retained on its natural bone support. Such a configuration may minimize the drawbacks of conventional explant culture, including chondrocyte death at cut surfaces and disruptions to the cells' microenvironment. Maintaining the biological and biomechanical properties of articular cartilage in a hemi-joint culture system would be beneficial for basic science studies on cartilage metabolism as well as storage applications for therapeutic allografts. The distal humerus of the elbow joint was harvested bilaterally from adult goat forelimbs and incubated in a static vessel in medium supplemented with 10% FBS for twelve days at 37⁰C. The chondrocytes from freshly explanted and cultured samples were largely viable in the full-thickness vertical profile (>85%) and in the superficial en face profile (>90%). The articular cartilage structural properties of thickness and stiffness, as well as the biochemical properties of collagen and DNA content were maintained with culture. The Glycosaminoglycan (GAG) content within the tissue decreased 36% in comparison to the freshly explanted samples. However, overall GAG in the culture system, determined as the sum of that remaining in the cartilage and released into the medium, increased 5%. Multiple regression analysis showed stiffness to be inversely correlated with cartilage thickness as well as positively correlated with GAG content. These results suggest that large joint segments consisting of articular cartilage on its natural bone support can be maintained at high viability during prolonged culture. Such culture methods may be useful for maintaining allografts with improved efficacy due to better maintenance of cell viability