A Study on Transdifferentiation of Bone Marrow Stromal Cells into Neuronal and Glial-Like Cells In Vitro by Different Inducers

There are some evidences to suggest that bone marrow stromal cells (BMSCs) not only differentiate into mesodermal cells, but also adopt the fate of endodermal and ectodermal cell types. BMSCs can be a valuable cell source as an autograft for clinical application involving regeneration of the central nervous system. Bone marrow stromal cells can be expanded rapidly in vitro and can be differentiated into neuronal- and glial-like cells. In this study, we attempted to devise a protocol or protocols for the induction of BMSCs into neuroepithelial- and neuroglial-like cells. Bone marrow was extracted from the femur and tibia of adult rat, and then bone marrow stromal cells with 4 passages were proliferated and cultured and then were evaluated with fibronectin by immunocytochemistry and Oct-4 by semi quantitative RT-PCR techniques. Also in this stage expression of Nestin, NF68, GFAP and O4 antibodies respectively markers of neuroepithelial, neuron, astrocytes and oligodendrocytes cells, were assessed. Rat BMSCs were differentiated by two consequent inductors into neuroepithelial, neuronal and glial-like cells. At pre-induction stage dimethyl sulfoxide (DMSO), β-mercaptoethanol (βME) or biotylated hydroxyanisol (BHA) were separately and without fetal bovine serum (FBS) added to alpha minimal essential medium (α-MEM), and then at induction stage the medium was replaced by retinoic acid (RA) and 15% FBS in α-MEM. Four days later, expressions of neuronal and glial markers were assessed. In addition, expression of NeuroD and Oct-4 mRNA were assessed in these cells. More than 92% of BMSCs was fibronectin positive at passage 4. A few percent of BMSCs differentiated into neuroepithelial and neuron-like cells but no astrocyte and oligodendrocyte-like cells were detected. Oct-4 mRNA was highly expressed in these cells while NeuroD mRNA expression was not detcted. Induction of BMSCs by DMSO-RA differentiated BMSCs into neuroepithelial and neuronal-like cells significantly compare to βME-RA and BHA-RA. Transdifferentiation of the treated BMSCs into astrocytes and oligodendrocyte-like cells was less than 5 %. Induction of BMSCs by DMSO-RA resulted in expression of NeuroD mRNA but Oct-4 mRNA was not expressed in none of treatment groups. Induction of BMSCs by different inducers specially DMSO-RA could highly transdifferentiate BMSCs into neuroepithelial and neuronal-like cells, whereas glial-like cells transdifferentiation was very low.