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 spontaneously differentiated into neural-like cells without any supplemental growth factors and/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 in a 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 the experimental group and ii.rat BMSCs (passage 5) as the control group. Each group was analysed by reverse transcriptase polymerase chain reaction (RT-PCR) to evaluate the expressions of neurotrophic factors and neural marker genes. Statistical analyses were carried out using one-way analysis of variance (ANOVA) and Tukey's multiple comparison with SPSS software (version 16). P< 0.05 was considered statistically significant. RESULTS The experimental group (fifth passage of BMSCs) obtained from adult rats spontaneously differentiated into neural precursor cells after long-term culture. Cultured cells expressed tyrosine hydroxylase (TH), Nurr1 and nestin genes. Furthermore, some growing cells 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 spontaneous transformation to neural precursors without the supplement of growth factors and specific chemicals. Cells expressed neural markers such as: TH, Nurr1, and nestin genes.