## 5 Discussion  
Current treatment strategies for the repair or replacement of bone with synthetic implants and stem cells are a new approach to treat different conditions occurring in the medical field. The fabrication of ceramic scaffolds adding the use of autologous _ah_MSCs is aimed at transplantation to a large bone defect site observed in some clinical conditions such as tumour surgery, infections, implant rescue in orthopaedic and oral surgery [2]. An ideal biomaterial scaffold designed for bone tissue engineering must be degraded over time into non-toxic products and requires osteeconductive, osteoinductive and osteogenic properties. Adding inorganic elements to scaffolds could significantly improve the bioactivity of materials as previously seen with bioglass, bioceramics that contain CaO, SiO2 and P2O5 or glass-ceramic [19; 20]. Also, these constructs could include additional growth factors or incorporate undifferentiated MSCs [21]. The osteoinduction of the materials was tested in this study, verifying their ability to lead _ah_MSCs toward an osteoblastic lineage differentiation. Firstly, we examined the shape of the cells cultured on SCP-c by FESEM and their metabolic activity. Theoretically, cells will be spherical initially, then flatten and later sufficiently spread out so that the nucleus becomes prominent [17; 22]. In our experiments, cells attached and adhered on SCP-c were found to be more spread out when they were cultured with OM. It has been noted that changes in expression of integrins, cadherins, and cytoskeletal proteins that occurs in the differentiation of stem cells produce cell morphological changes [23]. Moreover, previous studies have suggested that changes in cell shape can regulate the degree of development of lineage-specific markers, or differentiation, in precommitted preadipocytes or preosteoblasts [24; 25]. For all this, it is possible the morphological  
Figure 5: Real-time polymerase chain reaction (RT-PCR) was used to analyze the expression of genes RUNX2 (**A**), COL1A1 (**B**), BGLAP (**C**), ALPL (**D**), SPARC (**E**), IBSP1 (**F**) and SPP1 (**G**) in the cells seeded on the SCP-c scaffolds compared to cells cultured on plastic (positive controls). (*) denotes significant differences (\(p<0.05\)) between SCP-c and the control for the same experimental time; (\(\alpha\)) denotes significant differences (\(p<0.05\)) between different experimental times obtained for cells growing on SCP-c scaffolds; (\(\beta\)) denotes significant differences (\(p<0.05\)) between different experimental times obtained for control samples. changes observed are related to the differentiation of cells. Remarkably, _ah_MSCs cultured on SCP-c with OM showed major metabolic activity than cells cultured with GM after 28 days. Upon osteogenic induction, the copy number of mitochondrial DNA, protein subunits of the respiratory enzymes, oxygen consumption rate and intracellular ATP content are increased, indicating the upregulation of aerobic mitochondrial metabolism [26]. Therefore, a greater metabolic activity could be related to cellular differentiation mechanisms. The presence of the surface markers CD 105, 90, and 73 is considered as fundamental during the characterization and isolation of _ah_MSCs [27]; these markers were previously used by our research group to characterize _ah_MSCs from mononucleated fraction obtained by SEPAX isolation. The analysis of the cell surface markers showed that cells seeded in indirect contact with SCP-c exhibited a reduction of the expression of CD 105 and CD 90; this fact can be considered a consequence of the differentiation program activation [28]. A common method to evaluate the potential osteoinductivity of a novel biomaterial is to establish genetic expression profiles related to differentiation.