Fig. 7

Effect of BMP9 on bone mineralization and formation in the CIA model. (1) Double-labeling fluorescence results (A): Fluorescence labeling showed that new bone deposition was significantly reduced in the CIA group, with sparse green and red markings, indicating impaired mineralization dynamics. In contrast, the BMP9-treated group exhibited significantly increased new bone deposition compared to the CIA and CIA + GFP groups, with dense fluorescence labeling, approaching the levels observed in the control group. (2) Quantitative analysis (B–D): Mineral apposition rate (MAR) (B): The mineralization apposition rate in the BMP9 group was significantly higher than that in the CIA group (*p < 0.05), and was similar to the normal control group. Bone formation rate (BFR/BS) (C): The BMP9-treated group showed a significantly higher BFR/BS than both the CIA and CIA + GFP groups (**p < 0.01), almost reaching normal levels.Mineralized surface percentage (MS/BS) (D): The BMP9-treated group showed a significant increase in the percentage of the mineralized surface, with a significant difference compared to the CIA + GFP group (*p < 0.05)