Abstract: Objective To investigate the effect of lithium chloride(LiCl),an inhibitor of glycogen synthase kinase-3beta(GSK-3beta),on proliferation and differentiation of neural stem cells(NSCs).Methods The NSCs were isolated from cortex of rat fetus and expanded in culturing system.Their morphological changes and attachment process were observed under microscope.The cell cycle dynamics of NSCs was examined with flow cytometry.And the expression of GSK-3β and β-catenin was examined quantitatively with Western blot.Results The culturing NSCs treated with LiCl were usually floated and much dispersed in the media.Many of the neurospheres became small and the time of attachment after serum induction became longer.Using flow cytometry,it was detected that the proportion of G1 phase NSCs declined gradually accompanying the increased concentration of LiCl,while the percentage of S and G2/M phase cells showed an increasing trend.Western blotting results revealed β-catenin expression increased whereas Gsk-3βdecreased gradually under the treatment of LiCl and also showed a dose dependent manner.Conclusion These results suggest that LiCl may promote the proliferation of NSCs and prevent them from differentiating,which may partly involve the activation of wnt/β-catenin signaling pathway.

Key words: lithium chloride, neural stem cells, glycogen synthase kinase-3beta, proliferation, differentiation