Abstract: Objective To explore the effect of basic fibroblast growth factor (bFGF)-chitosan carriers on neural differentiation of neural stem cells (NSCs). Methods NSCs were isolated from spinal cord of a neonatal Wistar rat and cultured. Purity of cultured NSCs was identified with Nestin immunofluorescent staining. The 10 mg/ml chitosan carriers, 20 ng/ml bFGF or 10 mg/ml bFGF-chitosan carriers were added into medium of P3~P4 NSCs respectively. NSCs were observed with immunofluorescent staining: 3 days after incubation with Nestin and β-tubulin III; 7 days after incubation with microtubule-associated protein-2 (MAP2), glial fibrillary acidic protein (GFAP) and myelin basic protein (MBP); and 14 days after incubation with synapsin-1 and MAP2. The electrophysiological activity of cells was detected with MED64. Results 3 days after incubation, all the NSCs differentiated into Nestin+/β-tubulin III+, and the length of neurofilament was the highest in those co-cultured with bFGF-chitosan carriers. 7 days after incubation, NSCs differentiated into MAP2+, GFAP+ and MBP+, and more NSCs differentiated into MAP2+ with bFGF-chitosan carriers. 14 days after incubation, NSCs differentiated with bFGF-chitosan carriers express synapsin-1+/MAP2+ and showed electrophysiological activity. Conclusion bFGF-chitosan carriers can induce NSCs to differentiate into neuron with high percentage and the differentiated neurons can form synapses with electrophysiology activity.

Key words: neural stem cells, basic fibroblast growth factor, chitosan, neural differentiation, synapses, neurons