Spontaneous Expression of Neurotrophic Factors and TH, Nurr1, Nestin Genes in Long-term Culture of Bone Marrow Mesenchymal Stem Cells

Objective: It has been reported that rat bone marrow stromal cells (BMSCs) can be spontaneouslydifferentiated into neural-like cells without any supplemental growth factorsand/or chemical treatment after long-term culture.This study aims to determineWhether,growth factors secreted by MSCs could induce self-differentiation into neural-like cells ina long-term culture.Materials and Methods: This study consisted of two groups: i. rat BMSCs (passage 5)were cultured in alfa- minimal essential medium (α-MEM) and 10% fetal bovine serum(FBS) without the addition of inducer and exchanging medium for three weeks, as theexperimental group and ii.rat BMSCs (passage 5) as the control group. Each group wasanalysed by reverse transcriptase polymerase chain reaction (RT-PCR) to evaluate theexpressions of neurotrophic factors and neural marker genes.Statistical analyses were carried out using one-way analysis of variance (ANOVA) andTukey’s multiple comparison with SPSS software (version 16). P< 0.05 was consideredstatistically significant.Results: The experimental group (fifth passage of BMSCs) obtained from adult rats spontaneouslydifferentiated into neural precursor cells after long-term culture. Cultured cellsexpressed tyrosine hydroxylase (TH), Nurr1 and nestin genes. Furthermore, some growingcells in suspension became neurosphere-like. Self-differentiated rat MSCs (SDrMSCs)expressed significantly higher levels of NGF (0.96 ± 0.16), nestin (0.63 ± 0.08), and Nurr1(0.80 ± 0.10) genes (p<0.05).Conclusion: In this study, we reported that rMSCs in long-term culture underwent spontaneoustransformation to neural precursors without the supplement of growth factors andspecific chemicals. Cells expressed neural markers such as: TH, Nurr1, and nestin genes.