Objective    To compare the distribution and expression differences of glycogen synthase kinase-3β(GSK3β) among normal adult

aged and amyloid beta(Aβ)-induced neurodegenerative rat brains

so as to explore its functional role in neurodegeneration.     Methods    Aggregated Aβ 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 GSK3β were examined using immunohistochemistry. Western blotting was performed to assess expression change in cortex and hippocampus quantitatively.     Results    The GSK3β positive cells were distributed extensively around the whole brain and almost with neuron-like morphology. In normal adult rats

the strong anti-GSK3β immunoreactivity located in the neocortex pyramidal layer

hippocampus pyramidal layer

dentate gyrus

thalamus

substantia nigra

etc. The amount of GSK3β positive cells was much more in the aged and Aβ-injected group than in normal ones. The immunoreactive signals usually extend to the distal area of neurite in the Aβ-injected ones. Western blot showed that the expression intensity of GSK3β was stronger in the aged and neurodegenerative rat brain than in the normal adult rat brain.     Conclusion    The expression of GSK3β increases apparently in the neurons of aged and Aβ-injected brain. It may play a role in the neurodegenerative process.