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.
ABSTRACT
Objective To compare the distribution and expression differences of glycogen synthase kinase-3?(GSK3?) among normal adult,aged and amyloid beta(A?)-induced neurodegenerative rat brains,so as to explore its functional role in neurodegeneration. Methods Aggregated A? was microinjected into normal adult rat hippocampus under a stereotaxic system. The rats over 12 months were defined as aged rats. The distribution and localization of GSK3? were examined using immunohistochemistry. Western blotting was performed to assess expression change in cortex and hippocampus quantitatively. Results The GSK3? positive cells were distributed extensively around the whole brain and almost with neuron-like morphology. In normal adult rats,the strong anti-GSK3? immunoreactivity located in the neocortex pyramidal layer,hippocampus pyramidal layer,dentate gyrus,thalamus,substantia nigra,etc. The amount of GSK3? positive cells was much more in the aged and A?-injected group than in normal ones. The immunoreactive signals usually extend to the distal area of neurite in the A?-injected ones. Western blot showed that the expression intensity of GSK3? was stronger in the aged and neurodegenerative rat brain than in the normal adult rat brain. Conclusion The expression of GSK3? increases apparently in the neurons of aged and A?-injected brain. It may play a role in the neurodegenerative process.