Osteogenesis and new bone formation of alendronate-immobilized porous PLGA microspheres in a rat calvarial defect model

In this study, we evaluated in vitro osteogenic differentiation and in vivo new bone formation using the alendronate-releasing porous PLGA microsphere (Aln/PMS) system in rats with a critical-sized calvarial defect. Aln/PMS system significantly enhanced in vitro osteogenic differentiation and maturation, showing significantly enhanced ALP activity, calcium deposition and the expression of osteocalcin and osteopontin, relative to PMS alone. Also, micro-CT analyses and histology results suggested that Aln/PMS system increased mineralization and bone matrix formation compared to PMS alone. This study demonstrated that the local delivery of Aln, a potent-osteoinductive factor, significantly enhances rabbit adipose-derived stem cells osteogenesis and bone regeneration.