Chondrocytes within Osteochondral Grafts Are More Resistant than Osteoblasts to Tissue Culture at 37°C

• Published in: Journal of investigative surgery 2011-01, Vol.24 (1), p.28-34
• Main Authors: Bastian, Johannes D., Egli, Rainer J., Ganz, Reinhold, Hofstetter, Willy, Leunig, Michael
• Format: Article
• Language: English
• Subjects: allograft storage; Animals; Bone Transplantation; cartilage repair; chondrocyte; Chondrocytes - physiology; Humeral Head; osteoblast; Osteoblasts - physiology; Swine; Temperature; Tissue Culture Techniques; Transplantation, Homologous
• ISSN: 0894-1939; 1521-0553
• DOI: 10.3109/08941939.2010.523511

ABSTRACT It is proposed that an ideal osteochondral allograft for cartilage repair consists of a devitalized bone but functional cartilage. The different modes of nutrient supply in vivo for bone (vascular support) and cartilage (diffusion) suggest that a modulation of storage conditions could differentially affect the respective cells, resulting in the proposed allograft. For this purpose, osteochondral tissues from porcine humeral heads were either cultured at 37°C for up to 24 hr or stored at 4°C for 24 hr, the temperature at which osteochondral allografts are routinely stored. Functionality of the cells was assessed by in situ hybridization for transcripts encoding collagen types I and II. At 37°C, a time-dependent significant reduction of the bone surface covered with functional cells was observed with only 5% ± 5% coverage left at 24 hr compared with 41% ± 10% at 0 hr. Similarly, cartilage area containing functional cells was significantly reduced from 84% ± 7% at 0 hr to 70% ± 3% after 24 hr. After 24 hr at 4°C, a significantly reduced amount of functional cells covering bone surfaces was observed (27% ± 5%) but not of cells within the cartilage (79% ± 8%). In the applied experimental setup, bone cells were more affected by tissue culture at 37°C than cartilage cells. Even though chondrocytes appear to be more sensitive to 37°C than to 4°C, the substantially reduced amount of functional bone cells at 37°C warrants further investigation of whether a preincubation of osteochondral allografts at 37°C-prior to regular storage at 4°C-might result in an optimized osteochondral allograft with devitalized bone but viable cartilage.