Conclusion
Puerarin-enriched porous PTP scaffold was a promising local delivery system with sustained release of puerarin for facilitating defect repair through getting synergistic angiogenic and osteogenic effects. The translational potential of this article: The PTP scaffold presents a potential drug/device combination medical implant for large bone defect repair, which also provides a new and innovative application for the "old drug" puerarin.
Methods
Puerarin was incorporated into the poly (lactic-co-glycolic acid)/β-calcium phosphate (PLGA/TCP, PT) to form a porous PLGA/TCP/Puerarin (PTP) composite scaffold by low-temperature rapid prototyping technology. Its structural and degradation were analyzed in vitro. Then we employed a rat calvarial critical size defect model to assess the potency of the PTP scaffold. MC3T3-E1 cells and EA. hy 926 cells were used to investigate the underlying mechanism.
Results
PTP scaffold inherited all advantages of PT scaffold in structural, mechanical, and biodegradation, meanwhile puerarin stably and continuously released from PTP scaffold and lasted for 5 months in vitro. At 8 weeks after implantation, the PTP scaffold triggered new bone formation in the macro-pores of the scaffold and inside the scaffold accompanied by the degrading materials. The underlying mechanism revealed that the PTP scaffold induced vascular infiltration and recruit repair cells through stimulating vascular endothelial growth factor (VEGF) and bone morphogenetic protein 2 (BMP-2) expressions to promote angiogenesis and osteogenesis.