Icariside II-Loaded Calcium Phosphate Cement Scaffolds Combined with Bone Marrow Mesenchymal Stem Cells for Osteogenesis

Purpose: Previous studies have demonstrated the osteogenic effects of icariside II (ICSII), which is a metabolic product of the prenylated active flavonol icariin (ICA) from the roots of Epimedium. However, the in vivo osteogenic effects of ICSII remain unclear. Thus, in this study, we evaluated the osteogenic effects of ICSII in vivo. Methods: Complexes of calcium phosphate cement (CPC) and bone marrow mesenchymal stem cells (BMSCs) with or without ICSII were subcutaneously implanted into nude mice (ectopic osteogenesis test) and into tooth sockets in beagles after maxillary canine tooth extraction (in situ osteogenesis test). The samples were harvested at different time points, and the in vivo osteogenic effect of the ICSII on the BMSCs was evaluated by histology, microcomputed tomography (micro-CT) and the bone mineralization apposition rate (MAR). Results: The proliferation and viability of BMSCs in the ICSII-loaded CPC scaffold were significantly increased (P < 0.01). The new bone area and MAR in the CPC+BMSC+ICSII group were greater than those in the CPC+BMSC group (P < 0.05), but there was no significant difference in markers evaluated by immunohistochemistry and integrated optical density (IOD) analysis (P > 0.05), with the exception of Runx-2 expression in the CPC+BMSC+ICSII group. After 2 months, the bone mineral content (BMC) and specific bone surface (bone surface divided by bone volume, BS/BV) were significantly increased (P < 0.05) in the CPC+BMSC+ICSII group compared with the CPC+BMSC group. The bone mineral density (BMD), bone volume divided by total volume (BV/TV), and trabecular number (Tb.N) were increased in the CPC+BMSC+ICSII group, but the differences were not significant (P > 0.05). Conclusions: Our results suggest that ICSII can likely induce bone formation by BMSCs and be used as a promising factor for building scaffold composites in bone tissue engineering.