Abstract: OBJECTIVE: Inactivation of the Janus kinase 2(JAK2)/signal transducer and activator of transcription 3(STAT3) signaling axis plays a crucial role in determining the fate of neural stem cells(NSCs).Qingnaoyizhi decoction(QNYZD) has been used for the treatment of vascular dementia and has shown to improve synaptic remodeling. The aim of this study was to evaluate the effect of cerebrospinal fluid(CSF) containing QNYZD(CSF-QNYZD) on the differentiation of cultured NSCs and the involvement of the JAK2/STAT3 pathway.METHODS: The protein expression levels of glial fibrillary acidic protein(GFAP), tubulin, drosophila mothers against decapentaplegic protein(SMAD-1), STAT3, and phosphorylated-STAT3 were detected by western immunoblot analysis in the groups: control, CSF, JAK/STAT inhibitor(AG490),CSF-QNYZD, and CSF-XDZ(CSF-Xidezhen). The differentiation of NSCs was determined by immunofluorescence staining. The proliferation of NSCs was measured using the Cell Counting Kit-8 proliferation assay.RESULTS: Compared with the control group,CSF-QNYZD and AG490 significantly increased the number and expression of tubulin-positive cells, reduced the number and expression of GFAP-positive cells, and down-regulated the expression of p-STAT3. However, CSF-QNYZD also decreased the expression of SMAD-1 and STAT3.CONCLUSION: Enhanced neuronal differentiation may be associated with the down-regulation of glial differentiation instead of promoting proliferationin treated NSCs. Furthermore, QNYZD may play a direct role in suppressing the formation of GFAP-positive cells and enhancing neuronal differentiation by inhibiting JAK2/STAT3 activation. Overall, these results provide insights into the possible mechanism underlying QNYZD-mediated neurogenesis.

Key words: Neural stem cells, Glial fibrillary acidic protein, Cell differentiation, Janus kinase 2, STAT3 transcription factor, Qingnaoyizhi decoction