Abstract: Objective To investigate the potential mechanism of basic fibroblast growth factor (bFGF)-chitosan carrier to induce neural stem cells to differentiate into neurons. Methods After purification, the neural stem cells were cocultured with chitosan, soluble bFGF and bFGF-chitosan carrier. Three hours, twenty-four hours, three days and seven days after induction, immunofluorescence staining of Nestin, beta tubulin III, microtubule-associated protein-2 (MAP2), and fibroblast growth factor receptor 1 (FGFR1) were used to observe the expression of FGFR1; real-time fluorescent quantitative polymerase chain reaction (qRT-PCR) and Western blotting were used to detect RNA and protein level changes after induction. Results Three hours after induction, there was no significant difference in the expression of FGFR1 among three groups. Twenty-four hours after induction, the expression level of FGFR1 was significantly higher in the bFGF-chitosan carrier group than in the chitosan group and the soluble bFGF group (P<0.001); three days and seven days after induction, the expression of FGFR1 decreased significantly in the chitosan group and soluble bFGF group (P<0.001), however, it was still higher in the bFGF-chitosan carrier group; moreover, the expression of genes associated with the pathway of extracellular regulated protein kinases/mitogen activated protein kinase (Erk/MAPK) was significantly higher in the bFGF- chitosan carrier group than in the chitosan group and soluble bFGF group (P< 0.001). Conclusion bFGF-chitosan carrier might upregulate the expression of FGFR1, then activate Erk/MAPK signal pathways, and finally promote the differentiation of neural stem cells into neurons.

Key words: basic fibroblast growth factor, chitosan, neuron, neural stem cell, differentiation, rats