Fig. 5.

Bone mimetic ECM engineered by cocultured cells enhanced bone regeneration in vivo. (a) Schematic diagram of ECM ornamented SIS scaffolds implanted into mouse cavarial defects (Ф = 4 mm). The tissues with defects were collected after 3 or 6 weeks. (b–c) X-ray images of defects implanted with ECM-SIS scaffolds (M-ECM, MN-ECM and N-ECM) (n = 5) at 6 weeks (b). The relative new bone formation was calculated by normalization to new bone formation area in the defects with M-ECM scaffolds at 6 weeks, which was measured by ImageJ software (n = 5) (c). (d) H&E staining of the cross-sections to show the histological morphology of the regenerated defects at 6 weeks. Green dotted region represented newly formed bone (NB) (black arrow). The blue boxes were magnified to present the details of NB. HB: host bone; yellow arrow: marrow cavity. (e) MTS staining of the cross-sections of the regenerated defects at 3 and 6 weeks. Newly formed collagens were visualized as blue and newly formed mature bones were visualized as red. (f) Bone formation ratio was measured by ImageJ software based on H&E staining of cross-sections of the defects at 6 weeks. Sections with newly formed bone were measured for each mouse and 5 mice were analyzed for each group. (g) Collagen area with blue color and the whole scaffold area were measured by ImageJ staining, and the ratio was calculated. Five random fields were measured for each mouse and 5 mice were analyzed for each group. Scale bars represented 50 μm.