[Bio-absorbable Synthetic Polyesters and Tissue Regeneration. A Study of Three-dimensional Proliferation of Ovine Chondrocytes and Osteoblasts]

The tissue engineering area henceforth calls more and more for bioabsorbable substrata made of biopolymers (collagen, laminin...) or polymers (PLA, PLGA, PGA...) to realize the three-dimensional culture of tissue equivalents. The poly (beta-hydroxybutyrate-beta-hydroxyvalerate), a biopolymer considered as being biodegradable and biocompatible, has been recently introduced for orthopaedic biomaterials and regeneration purposes. In our study, a PHB/9% HV polymer was transformed into 3D foams, then applied to the culture 3D of ovine chondrocytes (fibrous rings & growth plates) and osteoblasts (periostum). Sponges made of bovine type I collagen were used as references. Orthopaedic cells were isolated, prepared and sown by simple injection to the geometrical center of the substrata, then incubated from 0 to 35 days by changing the culture medium all 4 days. Maximal densities were reached after 21 days: 18-24.10(6) cells/g for the chondrocytes, 8-10.10(6) cells/g for the osteoblasts. The cellular proliferation was more marked, with highest cell densities, for the collagen sponges. Laser confocal microscopy shows that the cellular diffusion take place throughout the entire volume of the porous artificial substrata. Future studies will allow to apply the porous bioabsorbable substrata to high-density cell cultures, to the tissue engineering and regeneration, for example for orthopaedic tissues: cartilage, fibrocartilage and bone.