A novel icariin-encapsulated PLGA/nBM composite biomimetic microspheres for bone repair

Deer bone in traditional Chinese medicine is valued for its unique biomimetic bone matrix components. Icariin (Ica), which is claimed by Chinese medicine as a bone-repairing agent, is also widely accepted. In this report, a novel Ica-encapsulated PLGA/nano deer bone meal (Ica@PLGA/nBM) biomimetic microsphere was fabricated. The Ica could be released from microspheres in a controlled manner. In vitro results showed that the microsphere had good biocompatibility due to the addition of nBM and the MC3T3-E1 cells could adhere to and grow well on the microspheres. Moreover, Ica and nBM in microspheres could synergically promote the ALP activity of MC3T3-E1 cells significantly ( p < 0.05), which indicated the acceleration of osteogenic differentiation. The RT-PCR results showed that the expression levels of bone matrix proteins (Col1 & OPN) were enhanced by the composite ( p < 0.05). In addition, Ica and nBM in microspheres also obviously promoted the expression of RUNX2 and BMP-2, respectively ( p < 0.05). The in vivo results demonstrated the effective promotion of Ica@PLGA/nBM on complete bony connection to cover the defect site and the bone defect repair. And the Ica(M)@PLGA/nBM microspheres provided the best repair results. All the results confirmed that the Ica@PLGA/nBM composite biomimetic microsphere has the potential for clinical application.