Thesis (Ph.D.) - Cairo University - Faculty of Veterinary Medicine - Department of Histology and Cytology

Sheep is the most abundant animal raised for food in Egypt. So, studying reproductive characteristics is important to improve management of this population. Therefore, this investigation focused on studying the histomorphology, histochemistry, electron microscopy, immunohistochemistry and immunofluorescence of the epididymis of ram. This study was conducted on 60 sexually mature ram (Rahmani breed) with average age ranged from (2_4) years and average weight ranged from (50_65) kg. After slaughtering of rams, small pieces from efferent ductules, initial duct, central caput, distal caput, corpus epididymis, proximal cauda epididymis and distal cauda epididymis were collected and examined. The epididymis of mature ram was composed of efferent ductules and epididymal duct. The efferent ductules were lined with a pseudostratified columnar epithelium with few intraepithelial lymphocytes were scattered frequently. The ciliated cells possessed kinocilia. The nonciliated cells were classified into three subtypes; type I cells (possessed numerous vacuoles), type II cells (contained both granules and vacuoles), and type III cells (had abundant granules). The epididymal duct was subdivided into six histological segments. Three of them were located in the caput, one in the corpus and two in the cauda epididymis. The epididymal duct was lined with a pseudostratified columnar epithelium which composed of two major cell types (principal cell and basal cell). Moreover, migrating cells (intraepithelial lymphocytes and macrophages) were frequently scattered throughout the epididymal duct. Other minor cell types had been observed in certain segments as apical cells and narrow cells. The principal cell was the only cell type which showed marked cytological differences among the different segments.Estrogen receptor alpha was strongly immuno_expressed in the nuclei of the nonciliated cells of the efferent ductules

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