Evaluation of the potential of novel PCL-PPDX biodegradable scaffolds as support materials for cartilage tissue engineering.

Cartilage is a specialized tissue represented by a group of particular cells (the chondrocytes) and an abundant extracellular matrix. Because of the reduced regenerative capacity of this tissue, cartilage injuries are often difficult to handle. Nowadays tissue engineering has emerged as a very promising discipline, and biodegradable polymeric scaffolds are widely used as tissue supports. In cartilage injuries, the use of autologous chondrocyte implantation from non-affected cartilage zones has emerged as a very interesting technique, where chondrocytes are expanded in order to obtain a greater number of cells. Nevertheless, it has been reported that chondrocytes in bidimensional cultures suffer a dedifferentiation process. The present study sought, in the first place, to standardize a novel protocol in order to obtain primary cultures of chondrocytes from newborn rabbit hyaline cartilage from the xiphoid process. Second, the potential of porous three-dimensional (3D) biodegradable polymeric matrices as support materials for chondrocytes was evaluated: a novel poly(ε-caprolactone)-poly(p-dioxanone) (PCL-PPDX) blend in a 90:10 w:w ratio and poly(ε-caprolactone) (PCL). After achieving the standardization, a typical round-shaped chondrocyte morphology and the expression of collagen type II and aggrecan, evaluated by RT-PCR, were observed. Second-passage chondrocytes adhered effectively to these scaffolds, although cell growth at 7 days in culture was significantly less in the PCL-PPDX blend. After 3 weeks of culture on PCL-PPDX or PCL, the cells expressed collagen type II. The present study demonstrates the potential, unknown until now, of PCL-PPDX blend scaffolds in the field of cartilage tissue engineering.