Gene Expression Pattern Of Neurotrophins And Their Receptors During Neuronal Differentiation Of Rat Bone Marrow Stromal Cells

Objective:To study the gene expression pattern of neurotrophins and their receptors during neuronal differentiation of rat bone marrow stromal cells (BMSCs) in vitro and explore a mechanism of the differentiation from bone marrow stromal cells into neurons.Methods:BMSCs were separated from rat bone marrow with percoll (1.073 g/mL) reagent and cultured in vitro. The induction of BMSCs to differentiate into neurons by means of dimethylsulfoxide (DMSO) and butylated hydroxyanisole (BHA) was done and observed, and morphological changes were observed and recorded under inverted microscope. The immunofluorescence method was used to identify the differentiated BMSCs which would express neuronal marker. The expression levels of neurotrophines NGF, BDNF , NT-3 and their high or low-affinity (TrkA,TrkB,TrkC, p75NTR) receptors before and at 2, 6, 12, 24 and 48h following the initiation of differentiation of BMSCs were investigated by RT-PCR.Results:1. Two hours after the induction, the differentiated BMSCs had morphological changes showed as ball-like shape with short prominence, like neurons. Immunofluorescence detection showed that the differentiated BMSCs expressed neuron marker neurofilament protein, but it was failed to detect the expression of astrocyte marker glial fibrillary acidic protein under this induction condition.2. The NGF and BDNF mRNA could be detected in BMSCs during the whole stage, and the expression levels of NGF mRNA gradually decreased after induction. Also RT-PCR revealed that both TrkA and TrkB expression were detected at 12h following the onset of differentiation while not expressed before. However no detectable expression of NT-3 and TrkC were observed in these cells either before or during differentiation.3. p75NTR appeared about 6h following the induction of differentiation and persisted until 12h time point, but significantly declined and quickly diminished thereafter.Conclusion:BMSCs can be induced to differentiate into neurons in vitro. Significant changes of the expression of neurotrophins (NT) NGF, BDNF , NT-3 and their high or low-affinity (TrkA,TrkB,TrkC,p75NTR) receptors were observed as BMSCs undergo neuronal differentiation. The signaling pathway of NT and their receptors may take part in the differentiation of BMSCs into neurons.