Fig. 7

Histologic analysis of the bone defect by H&E staining 4 weeks after mRNA administration. A Images in the bone-regenerating sites (4 × objective, scale bar = 500 µm). Although bone defects filled with scar tissue (S) and muscle (M) were still observed in all samples, increased bone mass (B) was observed in the Runx2 and VEGF coadministration group. B Images of the bone edge by magnifying the square areas in (A) (20 × objective, scale bar = 100 µm). In the Runx2 and VEGF coadministration group, the bone trabeculae were almost confluent (black arrow), and the bone marrow cavity became smaller (yellow arrow). C Masson–Goldner staining on serial sections of (B) (20 × objective, scale bar = 100 µm). In the Runx2 and VEGF coadministration group, newly formed unmineralized bone collagen frames (UB) occupied a smaller area (BD), with more calcified bone areas (CB)