Abstract: Objective To compare directed differentiation potential into neurons between neural stem cells(NSCs) from early embryonic rats and immortalized neural stem cell line C17.2(C17.2-NSC), and to establish a screening assay on the level of NSCs for high content screening in order to discover drugs that induce directed neurons differentiation of NSCs. Methods Three types of cells, the C17.2-NSC, 17 days embryonic hippocampus NSCs and 11 days embryonic cerebral cortex NSCs were used in this study. Cells from each type were divided into the control and experimental groups, and induced to differentiate by 0 μmol/L and 1 μmol/L retinoic acid (RA) for 5 days under DMEM/F12 medium containing 2%(V/V) B27 and 37℃, 5% CO2 normal culture condition. The variability of expression level of nestin and βⅢ tubulin (Tuj1), which are the specific markers of neural stem and progenitor cells and neurons, respectively, in both control group and experimental group were detected throughimmunohistochemistry. BR>Results Compared with the control group, C17.2-NSC did not differentiate into neurons under the induction of 1 μmol/L RA, but 17-day embryonic hippocampus NSCs and 11-day embryonic cerebral cortex NSCs effectively differentiated into neurons under the same treatment.Conclusion The directed differentiation capacity of early embryonic NSCs into neurons is higher than that of C17.2-NSC, thus early embryonic NSCs are suitable for high content drug screening which aims to discover new types

Key words: Neural stem cell, Neuron, Cell differentiation, Retinoic acid, Nestin, βⅢ tubulin, Immunohistochemistry, Rat