Simple evaluation method for osteoinductive capacity of cells or scaffolds using ceramic cubes

• Quantified in vivo bone formation for MSCs seeded porous ceramic cubes.
• Useful method for evaluating the osteoinduction ability of target cells.
• Simple and more accurate than critical sized bone defect model for analysis of osteoinduction.
• Can be applied for evaluation of scaffolds for their osteoinductive properties.

Mesenchymal stem cells are good candidates for the clinical application of bone repair because of their osteogenic differentiation potential, but in vivo osteoinduction potential should be verified for culture expanded cells before clinical application. This study analyzed in vivo bone formation by MSCs quantitatively after implantation of MSCs planted porous biphasic ceramic cubes into athymic mice. MSCs were divided into osteogenic differentiation-induced and normal groups and also tested in vitro to evaluate the degree of differentiation into osteoblasts. The osteogenic induced group showed higher alkaline phosphatase and calcium level in vitro and corresponding higher level of bone formation in vivo compared to control group. Whereas there was no bone formation observed in fibroblast-implanted negative control group. In critical sized bone defect models, commonly used for evaluation of bone regeneration ability, it is difficult to distinguish between osteoinduction and osteoconduction, and quantitative analysis is not simple. However, this method for evaluating osteoinduction is both accurate and simple. In conclusion, the analysis of in vivo bone formation using porous ceramic cubes is a powerful and simple method for evaluating the osteoinduction ability of target cells and, furthermore, can be applied for evaluation of scaffolds for their osteoinductive properties.