To determine the in vivo bone formation on an osteoblastic cells-scaffold composite and the best scaffold for bone formation. This study focused on the three-dimensional culture of osteoblastic cells using various tissue-engineered scaffolds and compared the suitability of those scaffolds.

Mesenchymal stem cells were harvested from New Zealand white rabbits and were differentiated into osteoblastic cells. The expression of osteogenic proteins in osteoblastic cells was observed by RT-PCR and a phase of mineralization was checked using von Kossa staining. In addition, three-dimensional cultured osteoblastic cells-scaffolds composites using a variable scaffold were observed by scanning electron microscopy. The cell-scaffold composites were transplanted into athymic nude mice. X-ray, a histochemical study, and immunohistochemistry were used to evaluate the in vivo bone formation.

The mesenchymal stem cells proliferated quite well in the early phase and differentiated into osteoblastic cells by an inducing substance. The osteoblastic cells were observed as spindle and polygonal shapes and were mineralized. Expression of the osteoblastic proteins was observed continuously after 2-3 weeks. The amount of osteocalcin secretion increased for 6-7 weeks. The osteoblastic cells adhered more to the human and porcine bone than to the hydroxyapatite-scaffold. In the case of the PLGA scaffold, the cells proliferated and formed a net-like structure but did not adhere well. No Living cells were observed in the calcium alginate scaffold. However, after the in vivo transplant, abundant cells and new tissue were observed within the human bone, porcine bone, hydroxyapatite, and PLGA but not within the calcium alginate scaffold.

In the three-dimensional cultures, natural bone was found to be a more effective and suitable scaffold for cell culture than the various synthetic polymers.