Production and evaluation of decellularized extracellular matrix hydrogel for cartilage regeneration derived from knee cartilage

Cartilage tissue engineering is the interdisciplinary science that will help to improve cartilage afflictions, such as arthrosis, arthritis, or following joints traumatic injuries. In the present work, we developed an injectable hydrogel which derived from decellularized extracellular matrix of sheep cartilage. Successful decellularization was evaluated by measuring the DNA, glycosaminoglycans (GAG), collagen contents, and histological analyses. There was a minor difference in GAG and collagen contents among natural cartilage and decellularized tissue as well as ultimate hydrogel. Rheological analysis showed that the temperature and gelation time of prepared hydrogel were 37 degrees C and between 5 and 7 min, respectively. Mechanical properties evaluation indicated a storage modulus of 20 kPa. The results show that prepared hydrogel possessed cell-friendly microenvironment as confirmed via calcein staining and MTT assay. Also, cells were able to proliferate which observed by H&E and alcian blue staining. Cell attachment and proliferation at the surface of the decellularized hydrogel was apparent by Scanning Electron Microscope (SEM) images and microphotographs. Furthermore, the cells embedded within the hydrogel were able to differentiate into chondrocyte with limited evidence of hypertrophy and osteogenesis in utilized cells which proved by SOX9, CoL2, ACAN, and also CoL1 and CoL10 gene expression levels. In summary, the results suggest that developed novel injectable hydrogel from decellularized cartilage could be utilized as a promising substrate for cartilage tissue engineering applications.