Figure 6: Critical-sized calvarial bone-defect repair.

(a) Cell-free NF PLLA scaffolds were directly coated with HP/miR-26a polypexes or the NC polyplexes (miR-26a-bolus or NC-bolus). (b) Cell-free NF PLLA scaffolds were immobilized with PLGA 6.5-K microspheres that contains HP/miR-26a polyplexes or NC polyplexes (miR-26a-HP-short or NC-HP-short). (c) Cell-free NF PLLA scaffolds were immobilized with PLGA 64-K microspheres that contains HP/miR-26a polyplexes or NC polyplexes (miR-26a-HP-long or NC-HP-long). The above six groups of scaffolds were implanted into 5-mm critical-sized calvarial bone defects of C57BL/6d mice. MicroCT images (left) and H&E staining (low magnification (mag) in the middle and high mag on the right) of calvarial defects were recorded after implantation for 2 months. (d) Quantitative microCT analysis showing the regenerated bone volumes and bone mineral densities in the six groups described above. Consistent with significantly increased neo bone volumes, the bone mineral densities of the short-term and long-term miR-26a release groups were also increased. *P<0.05; **P<0.01; #P<0.05; ##P<0.01. All experiments were carried out in triplicate. n=5 per group. Data are mean±s.d. Scale bars, 5 mm (in microCT images), 2.0 mm (in H&E images at right), 200 μm (in higher-mag H&E images at far right).