[Application of mechanically reinforced 45S5 Bioglass^®-derived bioactive glass-ceramic porous scaffolds for bone defect repairing in rabbits].

<b>Objective:</b> To evaluate the application of mechanically reinforced 45S5 Bioglass^®-derived glass ceramic porous scaffolds for repair of bone defect in rabbits. <b>Methods:</b> The BG-ZnB powders were added into the 45S5 Bioglass^® powder/paraffin microsphere mixtures and were sintered at 900℃ to obtain porous scaffolds with highly bioactive BG-ZnB of 0%, 2% or 4% of mass fraction (denoted as 45S5/ZnB0, 45S5/ZnB2, 45S5/ZnB4). Phase composition, porosity and compression properties of three kinds of as-sintered scaffolds were characterized by X-ray analysis, mercury porosimetry, and mechanical test. Thirty-six male New Zealand rabbits with critical-sized femoral bone defects were randomly divided into three groups (45S5/ZnB0 group, 45S5/ZnB2 group and 45S5/ZnB4 group, 12 for each), and were implanted with three kinds of porous scaffolds respectively. X-ray, micro-CT three-dimensional reconstruction and tissue slice staining were used to detected the efficiency of bone regeneration at 6 and 16 weeks after operation. The growth of newly formed bone was observed using HE, Masson staining and EnVision method. <b>Results:</b> Phase compositions of 45S5/ZnB2 and 45S5/ZnB4 were the same with 45S5/ZnB0, but the average pore size and porosity of the scaffolds were decreased with the increase of BG-ZnB content. 45S5/ZnB2 and 45S5/ZnB4 scaffolds exhibited higher compressive strength, osteogenesis and trabecular density than those of the 45S5/ZnB0 scaffold (all <i>P</i><0.05). With the mechanical reinforcement of BG-ZnB increased, the content of new bone, collagen type I and osteocalcin increased. <b>Conclusion:</b> Low-melt BG-ZnB-assisted sintering is a promising approach to improve the mechanical strength of 45S5 Bioglass^®.