Alveolar bone repair of rhesus monkeys by using BMP-2 gene and mesenchymal stem cells loaded three-dimensional printed bioglass scaffold

Abstract

Over the past years, the study about bone tissue engineering in the field of regenerative medicine has been a main research topic. Using three-dimensional (3D) porous degradable scaffold complexed with mesenchymal stem cells (MSCs) and growth factor gene to improve bone tissue repair and regeneration has raised much interest. This study mainly evaluated the osteogenesis of alveolar bone defects of animal in the following experimental groups: sham-operated (SO), 3D printed bioglass (3D-BG), 3D-BG with BMP-2 gene loaded CS (3D-BG + BMP/CS) and 3D-BG with rhesus marrow bone MSCs and BMP/CS (3D-BG + BMP/CS + rBMSCs). Simulated human bone defect with critical size of 10 × 10 × 5 mm were established in quadrumana - rhesus monkeys, and in vivo osteogenesis was characterized by X-ray, micro-Computed Tomography (mCT) and history. Our results revealed that 3D-BG + rBMSCs + BMP/CS scaffold could improve bone healing best by showing its promote osteogenic properties in vivo. Considering the great bone repair capacity of 3D-BG + BMP/CS + rBMSCs in humanoid primate rhesus monkeys, it could be a promising therapeutic strategy for surgery trauma or accidents, especially for alveolar bones defects.

Figure 1

SEM micrographs, XRD patterns and FTIR spectra showed the morphology (a), physical structure (b) and chemical structure (c) of 3D-BG scaffold. In vitro ions concentration (Si, Ca and P) in SBF after soaking with 3D-BG scaffold for day 0.5, 1, 3, 5 and 7, which indicated the forming process of calcium phosphate on 3D-BG scaffold’s surface (d).

Figure 2

SEM micrograph of the 3D-BG scaffold after soaking in SBF for different times: 1 day (a), 3 days (b), 5 days (c) and 7 days (d), which showed the deposition process of apatite on the surface of 3D-BG scaffold.

Figure 3

SEM micrograph of the 3D-BG scaffold finally applied in this study ((a): × 50, (b): × 1000).

Figure 4

SEM (a) and TEM (b) images showed the morphology and adhesion property of BMP/CS. Gel block assay (c) showed the bound property between pcDNA3.1(+)-BMP-2 and CS. Western blot assay (d~e) showed the effectiveness of BMP/CS.

Figure 5

In vitro rBMSCs proliferation (a) and osteogenic differentiation (b) on 3D-BG, 3D-BG + BMP, 3D-BG + CS and 3D-BG + BMP/CS scaffolds (*P < 0.05 vs 3D-BG; #P < 0.05 vs 3D-BG + CS; $P < 0.05 vs 3D-BG + BMP).Compared with other groups, 3D-BG + BMP/CS could promote rBMSCs proliferation (a) and osteogenic differentiation signifificantly.

Figure 6

X-radiography showed the different implantation areas after 12w ((a): BC, (b): 3D-BG, (c): 3D-BG + BMP/CS, (d): 3D-BG + rBMSCs + BMP/CS).

Figure 7

Micro-CT 3D reconstructions of implantation areas of rhesus monkey after 12 weeks, which showed the effect of bone regeneration ((a): SO, (b): 3D-BG, (c): 3D-BG + BMP/CS, (d): 3D-BG + rBMSCs + BMP/CS).

Figure 8

The bone volume of new alveolar bone in each group at 12-week post-operation (*P < 0.05 vs 3D-BG; ^#P < 0.05 vs 3D-BG + CS; ^$P < 0.05 vs 3D-BG + BMP).

Figure 9

Hematoxylin and eosin (H&E) staining of bone tissues after implanted in rhesus monkeys for 12 weeks, which showed the effect of bone tissue regeneration; × 100 and × 400 ((a): BC, (b): 3D-BG, (c): 3D-BG + BMP/CS, (d): 3D-BG + rBMSCs + BMP/CS).

Figure 10

Safranine and fast green (S&F) staining of bone tissues after implanted in rhesus monkeys for 12 weeks, which showed the effect of bone tissue regeneration; ×100 and ×400 ((a): BC, (b): 3D-BG, (c): 3D-BG + BMP/CS, (d): 3D-BG + rBMSCs + BMP/CS).