Apoptosis of Rat Adipose-Derived Stem Cells during Transdifferentiation to Schwann-Like Cell

Background: Adipose-derived stem cells (ADSCs) are a population of pluripotent cells used for tissue engineering purposes. The main purpose of the present study was to transdifferentiate the ADSCs to Schwann-like cells and to determine the intensity of apoptosis in ADSCs during the transdifferentiation process. Methods: ADSCs were isolated from the inguinal adipose tissue of adult rats and the identity of the undifferentiated ADSCs was confirmed by the detection of specific cells surface markers. The ADSCs were transdifferentiated by sequential administration of beta mercaptoethanol, all-trans retinoic acid and a mixture of forskolin, beta fibroblast growth factor, platelet derived growth factor and hergulin. The immunocytochemical properties of transdifferentiated Schwann-like cells were examined at specified time point. RT-PCR was used to investigate the gene expression of the undifferentiated and transdifferentiated ADSCs. Cell apoptosis was assessed with annexin/propidium iodide staining and 3-(4, 5-Dimethylthiazol- 2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Results: Expression of Schwann cell marker S100 was determined by immunocytochemical staining. RT-PCR analyses revealed that the induced ADSCs exhibited Schwann cellspecific markers such as S-100, P75, and glial fibrillary acidic protein on the 14th day. MTT assay and flow cytometry studies showed that of the total ADSCs in the differentiation medium, 50% of the cells died by apoptosis, but the remaining cell population remained strongly attached to the substrate and continued to differentiate. Conclusion: ADSCs could differentiate to Schwann-like cells in terms of morphology and phenotype. An increased cell death rate was noted and the principle mode of cell death was apoptosis.