FIG. 4.

In vivo histology and histomorphometric analysis. (A) Representative histology at 2 and 4 weeks postsurgery (decalcified; H&E stain; original magnification 2×). Both the BMSC/BMP2 and BMSC/BMP2/rhPDGF-BB groups showed extensive new bone formation at 2 and 4 weeks. In the BMSC/BMP2/rhPDGF-BB group, bone bridging that covered the central region of the defect area was observed. Arrow: margin of defect. (B) New bone area (mm²) at the defect site. Both the BMSC/BMP2 and BMSC/BMP2/rhPDGF-BB groups showed significantly higher amounts of new bone area at 2 weeks after surgery (ANOVA, p=0.003). However, there was no significant difference between the BMSC/BMP2 and BMSC/BMP2/rhPDGF-BB groups. At 4 weeks, the BMSC/BMP2/rhPDGF-BB group had significantly higher levels of new bone area compared to the other groups (ANOVA, p<0.001). (C) Defect closure (%) within the defects. Both the BMSC/BMP2 and BMSC/BMP2/rhPDGF-BB groups produced a significantly higher percentage of defect closure at 2 weeks (ANOVA, p<0.001). However, there was no significant difference between the BMSC/BMP2 and BMSC/BMP2/rhPDGF-BB groups. At 4 weeks, the defect closure of the BMSC/BMP2/rhPDGF-BB group was significantly higher than the other groups (ANOVA, p<0.001). Defect closure was measured as the ratio of the area of newly formed bone divided by the area of the whole defect. *Statistically different from the BMSCs and rhPDGF-BB groups. ^†Statistically different from the other groups. Values represent mean±SD of six samples.