1. Hospital of Plastic and Reconstructive Surgery, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100144, China
2. College of Chemical Engineering, Northwestern University, Xi’an 710069,China
3. Institute of Biomedical Research, Northwestern University, Xi’an 710069, China
Articular cartilage injuries and defects are a common and severe clinical challenge without effective treatment, and collagen-based hydrogels is a hotspot for cartilage tissue engineering, but there are still great challenges in developing collagen products with good biocompatibility and safe crosslinking, and the effectiveness of cartilage repair needs improving. In this study, recombinant type I collagen and recombinant type III collagen were crosslinked by EDC/NHS to prepare injectable hydrogels. The two hydrogels exhibited good three-dimensional pore structures, and excellent mechanical properties as well as degradability. It was found that recombinant type I collagen hydrogel (Gel-Ⅰ) and recombinant type III collagen hydrogel (GelⅢ) could promote the glycosaminoglycans secretion of HBMSCs. The effects of the hydrogels on the chondrogenic differentiation of BMSC were analyzed by RFqPCR, and it was found that Gel-Ⅰ significantly up-regulated COLII gene and SOX9 gene, and Gel-Ⅲ significantly up-regulated SOX9 gene. In the rabbit knee articular cartilage repair model, compared with the blank and Gel-Ⅲ groups, Gel-Ⅰ group showed the significant advantage in bone volume size, subchondral bone had been formed and effectively restored, the number and thickness of trabeculae were the highest, the trabeculaes were more uniformly distributed, and the thickness of the new cartilage at the defect was the same as that of the neighbouring cartilage. In conclusion, recombinant type I collagen hydrogel has great potential for clinical application in terms of the effectiveness and safety of cartilage repair.