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Background and Objective: Adult neurogenesis occurs in most mammalian species in two main areas of brain: 1- subventricular zone 2- the dentate gyrus of the hippocampus. Many factors such as 17-B estradiol affect neurogenesis in the hippocampus. The aim of this study was to investigate the effect of exogenous 17-B estradiol on neurogenesis and astrocyte functions in the ovariectomized mice.
Methods: In this experimental study; NMRI mice were allocated into five experimental groups including Sham, Control, Treatment with single dose of 17-B estradiol two weeks after ovariectomy (OVX) and were sacrificed 24 hours later, Treatment with single dose of 17-B estradiol two weeks after Ovx and were sacrificed 48 hours later and   Treatment with single dose of Seasame Oil 2 weeks after OVX and were sacrificed after 24 hours. Animals were transcardially perfused with paraformaldehyde. Brains were removed and its sections for cresyl fast violet staining and GFAP immunohistochemistry were prepared. Cells were counted and investigated.
Results: Neuronal density and Proliferation of hippocampal progenitor cells in the CA1 region of 17-B estradiol treated mice significantly increased up to 24 hours (P<0.05). Density of glia and particularly astrocytes in different regions of the hippocampus significantly reduced after treatment with 17-B estradiol (P<0.05).
Conclusion: Density of hippocampal CA1 neurons are influenced by 17-B estradiol. Also, density and morphology of glia cells, especially astrocytes in different regions of the hippocampus are affected by 17-B estradiol.