Evaluation of type II collagen scaffolds reinforced by poly(epsilon-caprolactone) as tissue-engineered trachea

A novel composite scaffold comprising a poly(epsilon-caprolactone) (PCL) stent and a type II collagen sponge for tissue-engineered trachea was developed. The PCL stent with surface grooves was fabricated by casting and freeze drying the PCL solution in a mold container. The grooves on the stent were filled by the type II collagen with crosslinking treatment (ring-shaped collagen sponge). The rabbit chondrocytes (3 x 10(6) cells for each ring) were seeded onto the collagen sponge of the scaffold. The cell-scaffold constructs were implanted subcutaneously in the dorsum of nude mice. After 4 and 8 weeks, constructs were harvested and dedicated for measurement of mechanical properties, histology, and biochemical assays. It was found that the constructs were strong enough to retain their tubular shape against extrinsic forces in the dorsum of nude mice. The gross appearance of the constructs revealed cartilage-like tissue at 8 weeks, with modulus higher than that of native trachea. Histological and biochemical analyses of the tissue-engineered tracheal cartilage revealed evenly spaced lacunae embedded in the matrix, with abundant proteoglycans and type II collagen. The stent-sponge composite facilitated the proliferation of chondrocytes and was expected to provide adequate mechanical strength, and therefore was a promising material for use in trachea tissue engineering.