Comparison of Proliferation and Osteoblast Differentiation of Marrow-Derived Mesenchymal Stem Cells on Nano- and Micro-Hydroxyapatite Contained Composite Scaffolds

Bones constructed by tissue engineering are being considered as valuable materials to be used for regeneration of large defects in natural bone. In an attempt to prepare a new bone construct, in this study, proliferation and bone differentiation of marrow-derived mesenchymal stem cells (MSCs) on our recently developed composite scaffolds of nano-, micro-hydroxyapatite/ poly(l-lactic acid) were compared with purepoly(l-lactic acid) scaffolds. For this purpose, some passaged-3 rat MSCs were three-dimensionally cultivatedon the scaffold surfaces and their morphology was observed with scanning electron microscopy. Cellproliferations on different scaffolds were examined by MTT assays. Osteogenic cultures were establishedwith the scaffolds loaded with MSCs for 21 days at the end of which culture mineralization; the cell alkalinephosphatase (ALP) Level and the relative expression of selected bone specific genes were quantified andcompared to each other. Our results indicated that the cells having been adhered and assumed sphericalmorphology were able to proliferate in all studied scaffolds. The microenvironment provided by nano-scaffoldsappeared much better medium than those of micro-scaffolds and pure PLLA (P < 0.05). The osteogenesisassays indicated to the superiority of nanoscaffolds in supporting MSCs undergoing bone differentiation,which was reflected in high cellular ALP levels, increased bone-related gene expression and enhanced culture mineralization. Collectively, the bone construct prepared with nano-hydroxyapatite/ poly (llactic acid) scaffold and proliferated MSCs would be suitable candidate for use in bone regenerative medicine.