Affiliations: Departments of Surgery and of Research, University Hospital Basel, Switzerland | Department of Medicine, Section of Emergency Medicine and Division of Engineering, Brown University, Providence, RI
Note: [] Address for correspondence: Ivan Martin, Institute for Surgical Research and Hospital Management, University Hospital Basel, Hebelstrasse 20, ZLF, Room 405, 4031 Basel, Switzerland. Tel.: +41 61 265 2384; Fax: +41 61 265 3990; E‐mail: imartin@uhbs.ch.
Abstract: Cartilage integration 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 paper, 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 μg/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‐O stained cross‐sections confirmed the reduced integration in the lubricin treated composites. Our findings suggest that the synovial milieu, by providing lubrication of cartilage surfaces, impairs cartilage–cartilage integration.
Journal: Biorheology, vol. 41, no. 3‐4, pp. 503-508, 2004
