In vitro and in vivo evaluation of chitosan–gelatin scaffolds for cartilage tissue engineering

Abstract

Chitosan–gelatin polyelectrolyte complexes were fabricated and evaluated as tissue engineering scaffolds for cartilage regeneration in vitro and in vivo. The crosslinker for the gelatin component was selected among glutaraldehyde, bisepoxy, and a water-soluble carbodiimide (WSC) based upon the proliferation of chondrocytes on the crosslinked gelatin. WSC was found to be the most suitable crosslinker. Complex scaffolds made from chitosan and gelatin with a component ratio equal to one possessed the proper degradation rate and mechanical stability in vitro. Chondrocytes were able to proliferate well and secrete abundant extracellular matrix in the chitosan–gelatin (1:1) complex scaffolds crosslinked by WSC (C1G1WSC) compared to the non-crosslinked scaffolds. Implantation of chondrocytes-seeded scaffolds in the defects of rabbit articular cartilage confirmed that C1G1WSC promoted the cartilage regeneration. The neotissue formed the histological feature of tide line and lacunae in 6.5months. The amount of glycosaminoglycans in C1G1WSC constructs (0.187±0.095μg/mg tissue) harvested from the animals after 6.5months was 14wt.% of that in normal cartilage (1.329±0.660μg/mg tissue). The average compressive modulus of regenerated tissue at 6.5months was about 0.539MPa, which approached to that of normal cartilage (0.735MPa), while that in the blank control (3.881MPa) was much higher and typical for fibrous tissue. Type II collagen expression in C1G1WSC constructs was similarly intense as that in the normal hyaline cartilage. According to the above results, the use of C1G1WSC scaffolds may enhance the cartilage regeneration in vitro and in vivo.