Enocyanin promotes osteogenesis and bone regeneration by inhibiting MMP9

Enocyanin (ENO), an anthocyanin extracted from grapes, has been shown to exert inhibitory effects on acid phosphatase and inflammation; however, its role in osteogenesis and bone formation is currently unknown. The present study aimed to investigate the effects of ENO on osteogenesis in vitro and bone formation in vivo, and to explore the rudimentary mechanisms. KusaO cells were employed to evaluate the osteogenic role of ENO in vitro by Alizarin red S staining, ALP staining, quantitative PCR and western blotting, and an in vivo analysis of the therapeutic effects of ENO on a femoral fracture model was performed using stereo microscope, micro-CT and histological staining. To further investigate the underlying mechanisms, mRNA sequencing was employed to investigate the changes in gene expression and the downstream pathways after ENO treatment. The results showed that ENO could promote the osteogenic differentiation of KusaO cells in vitro and bone fracture regeneration in vivo. Mechanistically, ENO was highly related to bone formation, including the 'Wnt signalling pathway', 'bone development' and 'bone mineralization'. In addition, matrix metalloproteinase 9 (MMP9) was identified as one of the targets of ENO in its promotional role in osteogenesis. In conclusion, ENO may represent a therapeutic candidate for bone regeneration in bone fractures by regulating osteogenesis and bone formation via MMP9.