en فاقدکاراکترفارسی است آناتومی آناتومی پژوهشي(توصیفی- تحلیلی) Research فاقدکاراکترفارسی است <strong><em>Background & Aims</em></strong><strong>:</strong> Adult neurogenesis occurs in the two main areas of the brain of most mammalian species in; sub ventricular zone, and the dentate gyrus of the hippocampus. Many factors such as 17-&beta; estradiol affect neurogenesis in the hippocampus. The aim of this study was to investigate the effect of exogenous 17-&beta; estradiol on neurogenesis in the ovariectomized (OVX) mice.<br> <strong><em>Materials & Methods</em></strong><strong>:</strong> NMRI mice were divided into five experimental groups: 1- Sham, 2- Control, 3- Treated with single dose of 17-&beta; estradiol two weeks after ovariectomy and euthanized 24 hours later, 4- Treated with single dose of 17-&beta; estradiol two weeks after OVX and euthanized 48 hours later, 5- Treated with single dose of Sesame Oil (vehicle) 2 weeks after OVX and euthanized after 24 hours. Animals were perfused transcardially with paraformaldehyde. Brains were removed and its sections for cresyl&nbsp;fast&nbsp;violet staining and Glial fibrillary acidic protein (GFAP) and BrdU immunohistochemistry were prepared. Cells were counted and investigated using light and fluorescent microscopy.<br> <strong><em>Results</em></strong>: Neuronal density and Proliferation of hippocampal progenitor cells in the CA1 region of 17-&beta; estradiol -treated mice were significantly increased up to 24 hours. The density of astrocytes in different region of the hippocampus was significantly increased after treatment by 17-&beta; estradiol.<br> <strong><em>Conclusion</em></strong>: Cell shape and density of hippocampal CA1 neurons are influenced by 17-&beta; estradiol. In addition, density and morphology of glial cells, especially astrocytes in different regions of the hippocampus are affected by 17-&beta; estradiol. Thus, 17-&beta; estradiol can improve neurogenesis in the CA1 region of the hippocampus. 17-β estradiol, Ovariectomy, Neurogenesis, Hippocampus, Dentate Gyrus 17-β estradiol, Ovariectomy, Neurogenesis, Hippocampus, Dentate Gyrus 511 521 http://umj.umsu.ac.ir/browse.php?a_code=A-10-3371-2&slc_lang=en&sid=1 Maryam Azari Maryam Azari ghorbanian@du.ac.ir 3700319475328460022152 3700319475328460022152 Yes School of Biology and Institute of Biological Sciences, Damghan University, Damghan, Iran فاقدکاراکترفارسی است Mohammad Taghi Ghorbanian Mohammad Taghi Ghorbanian ghorbanian@du.ac.ir 3700319475328460022153 3700319475328460022153 No School of Biology and Institute of Biological Sciences, Damghan University, Damghan, Iran فاقدکاراکترفارسی است