Repair of Cartilage Defects Using ATDC5 Cells Treated with BBR Loaded in Chitosan Hydrogel

In this study, we explore the cartilage defect repair mechanism by phosphocreatine-grafted chitosan hydrogels loaded with berberine-treated ATDC5 cells (CSMP@BBR@ATDC5). Under the optimal concentrations of LPS and BBR ideal conditions, ATDC5 cell toxicity and proliferation were detected with AM/PI and EdU staining. Additionally, qPCR and Western blot were employed to detect the expression of the SIRT1/BMP4 signaling pathway and chondrogenic-related factors in ATDC5 cells. Moreover, BBR-treated ATDC5 was seeded into a phosphocreatine-grafted chitosan hydrogel system. Subsequently, the cartilage defect was established in mice. After 4, 8, and 12 weeks, knee specimens were collected to evaluate the repair of cartilage defects. According to our findings, BBR can increase ATDC5 viability by LPS treatment. Likewise, it upregulates the SIRT1/BMP4 signaling pathway expression and chondrogenic-related factors. Another, it was shown by histological observation that the cartilage defect had been repaired more effectively in the CSMP@BBR@ATDC5 group than in the other groups. Finally, the expressions of chondrogenic-related factors and SIRT1/BMP4 signaling pathway were upregulates in CSMP@BBR@ATDC5 than in other groups. In vitro, BBR protects inflammatory ATDC5 cells and maintains the expression of chondrogenic-related factors. Subsequently, we successfully use CSMP@BBR@ATDC 5 to repair knee cartilage defects in mice.