Estrogen protects learning memory and hippocampus neurons in rats with Alzheimer's disease

Objective: To study the effects of estrogen on the impairment to learning memory and hippocampus neurons in rats with Alzheimer's disease(AD),and to explore its mechanism of neuroprotection.Methods: Twenty-four female rats were equally randomized into a normal control,an AD+E2 and an AD group.The performance of learning memory was tested by Morris water maze,the tau hyperphosphorylation and the activity of GSK-3β detected by immunohistochemical staining,and the pathological changes of hippocampus observed by H-E and Bielschowski staining.Results: Compared with the AD group,results showed a significant improvement in the performance of learning memory(P0.01),regular morphology of the neurofibrils in the hippocampus,a remarkable decrease in the number of P-Tau positive cells(P0.01),as well as in the total amount of GSK-3β and the content of phosphorylation of GSK-3βand Tau protein in the hippocampus.Conclusion: Estrogen can improve Aβ-induced impairment to learning memory and hippocampus neurons in AD rats.The neuroprotection mechanism of estrogen may be involved in its dephosphorylation of the Tau protein by alteration of GSK-3β.