Bioactive Glass-Polycitrate Hybrid with Osteogenetic Ability Comparable to Autogenous Bone.

Abstract

Significant progress in artificial bone grafts has been achieved in recent years. However, none of them has osteogenic ability that is close to autogenous bones. Hence, improving osteogenic ability of artificial bone is the most prominent and challenging task in this field. In addition, angiogenesis could provide a stable environment and nutrients for survival of the cells and also plays a crucial role to the success of bone transplantation. In the present study, we combined citrate polymer and bioactive glass together as hybrids at the molecular level (PEC-GS/BG), with the expectation of acquiring osteogenic ability and angiogenic ability to repair bone defect that could comparable to autogenous bones. In vitro and in vivo experiment on the femoral condyle critical defects model of Sprague-Dawley rats were conducted for a complete evaluation. In vivo, the bone mineral density (BMD) in defects was no significant difference between autogenous bone groups (517 ± 21 mg/cm³) and PEC-GS/BG groups (509 ± 21 mg/cm³) (p > 0 05) at 12 weeks post-surgery. The BMD of the femoral condyle in normal males at the same age was measured to be 557 ± 16 mg/cm³, only slightly higher than the above date, indicating a nearly complete repair of the defects. It was also found that PEC-GS/BG promoted angiogenesis due to it stimulated organism to release vascular endothecial growth factor (VEGF). PEC-GS/BG also showed great osteogenic ability that was close to autogeneous bones, but much better angiogenic ability. What's more, from both protein and cell levels, PEC-GS/BG accelerated differentiation and mineralization of MC3T3E-1 cells. Consequently, osteogenetic performance of PEC-GS/BG was almost same to autogenous bones in repairing bone defects. Considering the high demand in bone grafts and all the difficulties in autogeneous bone supply, the PEC-GS/BG hybrids developed in this study may open a new horizon for bone repair.