Figure 5: New bone formation in a subcutaneous implantation model.
From: Cell-free 3D scaffold with two-stage delivery of miRNA-26a to regenerate critical-sized bone defects
Continuous high-efficiency delivery of miR-26a significantly increases ectopically formed bone volume in vivo through elevating the expression levels of the key osteogenic factors for a prolonged time. Polymer HP3/miR-26a or NC polyplexes (miR-26a-bolus/NC-bolus) (a), HP3/miR-26a or NC polyplex-loaded PLGA 6.5-K microspheres (miR-26a-HP-short/NC-HP-short) (b) and HP3/miR-26a or NC polyplex-loaded PLGA 64-K microspheres (miR-26a-HP-long/NC-HP-long) (c) were attached directly to PLLA scaffolds, seeded with ∼1 × 105 bone marrow mesenchymal stem cells, and subcutaneously implanted into immunocompromised mice for 2 months. MicroCT images (left) and haematoxylin and eosine staining images (right) of the implants are reported. Formation of bone (B) and connective tissue (CT) around the PLLA scaffolds are highlighted (c). The new bone volume and bone mineral density from these groups are quantified (d). (e) Pattern and time course changes of early-stage and late-stage osteogenic genes in the implants (including Runx2, Alp, OCN and BSP) among the six groups from days 3 to 60 were determined with real-time RT–PCR. **P<0.01; #P<0.05; ##P<0.01. All experiments were performed in triplicate. n=5 per group. Data are mean±s.d. Scale bars, 1 mm (in microCT images), 500 μm (in haematoxylin and eosin (H&E) images at right), 200 μm (in higher-magnification H&E images at far right).
