Articular chondrocyte passage number: Influence on adhesion, migration, cytoskeletal organisation and phenotype in response to nano- and micro-metric topography

The isolation and culture of articular chondrocytes is a prerequisite of their use in tissue engineering, but prolonged culture and passaging is associated with de-differentiation. In this paper we studied the influence of nanometric and micrometric grooves (85 nm to 8 μm in depth and 2 μm to 20 μm in width) on 1st and 2nd passage ovine chondrocytes since our earlier findings indicate that primary cells are not affected by such features. 1st and 2nd passage chondrocytes cultured on grooved substrata showed a polarisation of cell shape parallel to the groove long axis and F-actin condensations were evident at groove ridge boundaries. An increase in cell migration with increasing groove depth was observed. Both passages of chondrocytes maintained type II collagen expression, but to a lesser degree in 2nd. This study demonstrates that passage number alters the response of chondrocytes to micrometric and nanometric topography, and could be important in ex vivo cartilage engineering.