Cell-mediated injectable blend hydrogel-BCP ceramic scaffold for in situ condylar osteochondral repair

The existing approaches for healing mandibular condylar osteochondral defects, which are prevalent in temporomandibular joint disorders (TMD), are sparse and not reparative. To address this, regenerative medicine in situ has transpired as a potential therapeutic solution as it can effectively regenerate composite tissues. Herein, injectable self-crosslinking thiolated hyaluronic acid (HA-SH)/type I collagen (Col I) blend hydrogel and BCP ceramics combined with rabbit bone mesenchymal stem cells (rBMSCs)/chondrocytes were used to fabricate a new bi-layer scaffold to simulate specific structure of rabbit condylar osteochondral defects. The in vitro results demonstrated that the blend hydrogel scaffold provided suitable microenvironment for simultaneously realizing proliferation and chondrogenic specific matrix secretion of both rBMSCs and chondrocytes, while BCP ceramics facilitated rBMSCs proliferation and osteogenic differentiation. The in vivo results confirmed that compared with cell-free implant, the rBMSCs/chondrocytes-loaded bi-layer scaffold could effectively promote the regeneration of both fibrocartilage and subchondral bone, suggesting that the bi-layer scaffold presented a promising option for cell-mediated mandibular condylar cartilage regeneration.