Introduction : The main purpose of this study was differentiation of bone marrow stem cells (BMSCs) into Schwann-like cells and to determine the intensity of apoptosis in BMSCs during the differentiation process.
Material and methods : Bone marrow stem cells were isolated from the femur of adult rats and the identity of the undifferentiated BMSCs was confirmed by the detection of specific cell surface markers. The BMSCs were differentiated by sequential administration of β-mercaptoethanol and all-trans-retinoic acid as pre-inducer factors and a mixture of forskolin, basic fibroblast growth factor, platelet-derived growth factor-AA and heregulin-b1 as inducer factors. The immunocytochemical properties of differentiated Schwann-like cells were examined at a specified time point. Reverse transcription-polymerase chain reaction (RT-PCR) was used to investigate the gene expression of the undifferentiated and differentiated BMSCs. Cell apoptosis and viability were assessed with annexin V and propidium iodide double staining and dimethylthiazol-2-yl-2, 5-diphenyltetrazolium bromide (MTT) assay.
Results : Immunocytochemistry staining and RT-PCR analysis revealed that the induced BMSCs exhibited Schwann cell-specific markers such as S-100, P75 and glial fibrillary acidic protein (GFAP) at the 14^th day of differentiation. MTT assay and flow cytometry revealed that of the total BMSCs in the differentiation medium, 40% to 50% of the cells died by apoptosis, but the remaining cell population remained strongly attached to the substrate and differentiated.
Conclusions : These findings indicated that BMSCs could differentiate into Schwann-like cells. As a side effect of differentiation an increased cell death rate was noted and our findings indicate that the principle mode of cell death is by apoptosis.