Fig. 3

Histologic views of newly formed bone in 5-mm defect samples. a MSC-CM group, b MSC-CM + anti-VEGF group, c PBS group, and d Defect group. The left image in each group is shown at low magnification (×12.5) and the right image shows a high magnification (×200) view of the framed area of the left image. Hematoxylin and eosin staining was performed. In the MSC-CM group, the defect was filled with newly formed bone although the defects were filled with fibrous connective tissue with a residual collagen scaffold in other groups. In the MSC-CM + anti-VEGF group, the defect was almost covered with fibrous connective tissue and fewer newly formed bone was observed at the cutting edge of the defect