Effect of conditioned medium by mesenchymal stem cells overexpressing bone morphogenetic protein 9 on osteoblast differentiation and bone regeneration

Abstract

Cell therapy approaches using bone marrow-derived mesenchymal stem cells (MSCs) have been investigated in the field of Dentistry and Medicine as a promising alternative to treat bone defects. Bone morphogenetic proteins (BMPs) are cytokines of the transforming growth factor beta (TGF-a) family and are involved in several biological processes, including osteoblastic differentiation and osteogenesis. Among the several BMPs, BMP-9 is considered one of the most osteogenic. Preliminary data of our research group have shown that MSCs overexpressing BMP-9 (MSCsBMP-9) injected into rat calvarial defects increase bone formation compared to MSCs without BMP-9 overexpression. These results may be explained, at least in part, by the fact that MSCsBMP-9 secrete bioactive molecules, which are accumulated in the culture medium when these cells are cultivated, that exert beneficial effects in the cells of the region of interest. In this context, the aims of this study are: (1) to characterize the conditioned media from MSCsBMP-9 regarding the presence of cytokines, growth factors and proteases, (2) to evaluate the effect of MSCsBMP-9 conditioned medium on migration, proliferation and osteoblastic differentiation of mouse bone marrow-derived MSCs and (3) to evaluate the effect of MSCsBMP-9 conditioned medium on bone regeneration of mouse calvarial defects. Quantitative data will be subjected to the normal curve adherence test to determine the appropriate statistical test to be applied, and the level of significance will be set at 5%. (AU)