Lubricin reduces cartilage-cartilage integration

摘要

Cartilage integiation in vivo does not occur, such that even cartilage fissures do not heal This could be due not only to the limited access of chondrocytes to the wound, but also to exogenous factors. In this papei, we tested the hypothesis that lubricin, a lubricating protein physiologically present in the synovial fluid, reduces the integrative cartilage repair capacity Disk/ring composites of bovine articular cartilage were prepared using concentric circular blades and cultured for 6 weeks with or without treatment with 250 /Ug/ml lubricin applied three times per week Following culture, the percentage of contact area between the disks and the rings, as assessed by light microscopy, were equal in both groups. The adhesive strength of the integration interface, as assessed by push-out mechanical tests, was markedly and significantly lower in lubricin-treated specimens (2.5 kPa) than in the controls (28 7 kPa). Histological observation of Safranin-0 stained cross-sections confirmed the reduced integiation in the lubricin treated composites Our findings suggest that the synovial milieu, by providing lubrication of cartilage surfaces, impairs cartilage-cartilage integration.