The microstructure of the newly formed bone was also evaluated in each group using micro-CT imaging. The majority of the orbital bone defects were filled with a substantial amount of newly formed bone tissue in the anti-miR group (
Fig. 3A). In the sagittal view, a small amount of nondegraded and residual β-TCP material was distributed among the new bone. A small amount of new bone and a large amount of β-TCP material residue and honeycomb scaffold structure could also be found in the peripheral area of the repaired defect (
Fig. 3A). The quantity of newly formed bone within the defects was determined using commercial software (GE Healthcare). The percentage of new bone volume relative to tissue volume (BV/TV) in the miR-Neg group (36.32% ± 5.40%) was significantly lower (
P < 0.05) than that in the anti-miR group (41.82% ± 6.54%), but was markedly higher (
P < 0.05) than that in the miR-31 group (20.50% ± 3.47%;
Fig. 3B). Furthermore, the BMDs were 0.460 ± 0.053 g/cm
3 in the miR-Neg group, 0.278 ± 0.046 g/cm
3 in the miR-31 group, and 0.607 ± 0.042 g/cm
3 in the anti-miR group (
Fig. 3C), showing the same pattern as the BV/TV ratios. These findings suggest that miR-31 impairs the potential of BMSCs in promoting orbital bone repair.