Spontaneous expression of neurotrophic factors and TH, Nurr1, nestin genes in long-term culture of bone marrow mesenchymal stem cells

ABSTRACT

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 determine whether, growth factors secreted by MSCs could induce self-differentiation into neural-like cells in a long-term culture. This study consisted of two groups i. rat BMSCs [passage 5] were cultured in alfa- minimal essential medium [alpha-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. 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]. 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