Glycosaminoglycan/Chitosan Hydrogel for Matrix-associated Autologous Chondrocyte Implantation: An In Vitro Study

Matrix-associated autologous chondrocyte implantation (MACI) is an effective treatment for full-thickness cartilage and osteochondral lesions with encouraging outcomes. However, problems include abnormal growth of chondrocytes during cultivation, cell dedifferentiation, and abnormally regenerated cartilage. A matrix that provides a physicochemical and biological microenvironment for restoring hypertrophic chondrocytes would be beneficial for MACI. Accordingly, this study evaluates the feasibility of using an injectable glycosaminoglycan (GAG)/chitosan hydrogel for MACI. Chitosan gel was prepared and GAGs (hyaluronan and chondroitin-6-sulfate) were added to fabricate a GAG/chitosan matrix. Porcine chondrocytes were isolated from articular cartilage and encapsulated within the GAG/chitosan matrix. Cell viability, material-mediated cytotoxicity, cellular proliferation, collagen production, GAG content, and mRNA gene expression patterns of the chondrocytes were evaluated. The cell viability and material-mediated cytotoxicity assay results show that the GAG/chitosan hydrogel has good biocompatibility. Chondrocytes cultured within the matrix had a slower proliferation but higher GAG production compared to those obtained for a monolayer culture. Real-time polymerase chain reaction results show that the mRNA expression of type II collagen was up-regulated but types I and X collagens were down-regulated. This study demonstrates that incorporating GAGs into a chitosan matrix maintains the normal phenotype of chondrocytes, making the GAG/chitosan matrix a candidate for MACI.