Biostable scaffolds of polyacrylate polymers implanted in the articular cartilage induce hyaline-like cartilage regeneration in rabbits

Abstract

[EN] Purpose: To study the influence of scaffold properties on the organization of ¿in vivo¿ cartilage regeneration. Our hypothesis is that stress transmission to the cells seeded inside the scaffold pores or surrounding it, which is highly dependent on the scaffold properties, determine differentiation of both mesenchymal cells and dedifferentiated autologous chondrocytes. Methods: Four series of porous scaffolds made of different polyacrylate polymers, previously seeded with cultured rabbit chondrocytes or without cells preseeded, were implanted in cartilage defects in rabbits. Subchondral bone was always injured during the surgery in order to allow blood to reach the implantation site and fill scaffold pores. Results: Three months after implant, excellent tissue regeneration was obtained, with a well-organized layer of hyaline cartilage at the condylar surface in most cases of the hydrophobic or slightly hydrophilic series. The most hydrophilic material induced the poorest regeneration. However, few variations were observed between the preseeded and non-preseeded scaffolds. All the materials employed were biocompatible, biostable polymers, therefore, in contrast to other studies, our results are not perturbed by possible effects attributable to material degradation products, or to the loss of scaffold mechanical properties over time due to degradation. Conclusions: Cartilage regeneration mainly depends on the properties of the scaffold, such as stiffness and hydrophility, whereas little differences were observed between preseeded and non-preseeded scaffolds.