Histological, ultrastructural and immunohistochemical study of the effect of estrogen intake on the thymus of female albino rat before and after puberty

This study was conducted on 24 healthy female albino rats to domenstrate histological and immunohistochemical changes which may occur in the thymus after injection of diethylstilbestrol. The animals were divided into two main groups [12 animals each]: prepubertal and postpubertal. Each group were subdivided into control and treated groups [6 animals each]. The control groups were subcutaneously daily injected with corn oil. While, the treated groups were injected with 17.5 microg/ 100 grams body weight of diethylstilbesterol. After 14 days of injections. the thymuses were dissected, divided into two parts, one for histological and estrogen receptors study, while the second part for ultrastructural study. The thymus of the control prepubertal group appeared with many packed thymocytes and dark star shaped reticular epithelial cells in-between. However, control postpubertal thymus appeared with mild thickening of interlobular septa, less packed thymocytes. Many cells noticed with small electron dense nuclei, peripheral condensation of heterochromatin, irregular nuclear membrane and unrecognized cell organoids [apoptotic cells]. In addition to pale cells with large wide processes and dark star shaped cells with slender narrow processes in-between thymocytes. Sections of treated prepubertal thymus glands showed, thickening of the thymic capsule with fat infiltration and loss of distinction between the cortex and medulla. There was an increase in the number of Hassall s corpuscles and large reticular cells with large pale nuclei and pale cytoplasm in the thymic medulla. Additionally, transmission electron microscope study of this group revealed, many cells at different stages of apoptotsis. However, treated postpubertal thymus appeared with marked depletion of the cortical thymocytes of some Lobules and many cells at different stages of apoptosis. The immuriostainirig for estrogen receptor showed that, estrogen receptor was expressed in some thymic cells of the cortex especially, the subcapsular, around interlobular septa and at the corticomedullary zones. However, the thymocytes appeared negatively reacted. In the medulla, the Hassall s corpuscles were weak positively reacted. The intensity of the reaction appeared varied according to the age of the animals and appeared to increase after the treatment. In conclusion, estrogen administration revealed many histological and immunohistochemical changes in pre and postpubertal thymuses which may alter the immune responses. So, contraception methods must be chosen carefully especially in young aged females

Histological study and epidermal growth factor changes in rabbit olfactory mucosa at different ages

This study was conducted to investigate the histological structure of the rabbit olfactory epithelium at different ages, in addition to evaluate the epidermal growth factor localization in this organ. Two fetuses and six healthy male rabbits were used at the following stages [two animals each]: neonatal, adult and aged Upon sacrifaction, the olfactory epithelium of each animal was prepared for general histological structure and with improved Biotin-Streptavidin amplified detecting staining methods to localize the sites of epidermal growth factors.The olfactory mucosa of fetal and neonate rabbit specimens was uniform, resting on a richly vascularized lamina propria and houses serous glands. The luminal surface showed dark line and tangled with meshwork of microvilli and cilia on the surface.Within the olfactory epithelium thickness there were many layers of nuclei which was difficult to distinguish individual cell types. Positive iminunoreactions were noticed in all layers of the fetal and neonatal olfactory epithelium stained by anti-epidermal growth factor polyclonal IgG. The olfactory mucosa of adult rabbit specimens was noticed irregularly arranged; diminished thickness with scattered few goblet cells. Lamina propria was noticed supported by thicker loose connective tissue. Positive immunoreactions were noticed confined in the basal layer of adult olfactory epithelium.The olfactory mucosa of aged rabbit specimens was noticed irregularly arranged and with diminished thickness and tangled with variable length of microvilli and cilia on the surface. Apical cells were noticed with apical oval nuclei and their luminal borders had microvilli. Thick lamina propria appeared and houses less number of serous glands with pyknotic nuclei in their cells. Positive immuno reaction to epidermal growth factor was identified only in the basal layer of the aged olfactory epithelium and the number of regions in which EGF were identified in the basal layer decreased compared to adult one.The present data suggest that, the number of proliferating cells in the olfactory epithelium decreased rapidly with age. These changes in proliferating cells, which seem to result in atrophy of the olfactory epithelium, coincided with changes in epidermal growth factors in the olfactory epithelium of rabbit

Histological and immunohistochemical studies of the rabbit ovary at different physiological conditions

This study was conducted on twenty healthy female balady rabbits to investigate the histological structure of the rabbit ovary at different physiological conditions, in addition to evaluate cytokeratin 7 localization in this organ. The animals were classified into four groups each comprised five animals: neonates, adult non-pregnant non-lactating, adult pregnant and adult lactating rabbits. Upon sacrifaction, ovaries samples were prepared for general histological structure and with improved Biotin-Streptavidin amplified detecting staining methods to localize the sites of intermediate filaments cytokeratin 7. Moreover, minute parts were prepared for transmission electron microscope examination.Light microscopic examination of the ovarian sections showed an outer broad cortex and an inner narrow medulla with no line of demarcation in between. Also, a dense tunica albuginea was organized under the covering epithelium and appeared well developed in adult pregnant rabbit ovary. The cortex, in neonates contained only primordial follicles which differentiated to various ovarian follicles at adult ages. But, it was noticed that atretic follicles were found more abundant in the ovarian cortex during pregnancy. The medulla was formed of fibrovascular connective tissue stroma which became more vascular with pregnancy. The corpus luteum of pregnancy was large in size and accounted for more than one half the volume of the ovary and characterized by the presence of numerous lipid droplets in the small luteal cells cytoplasm. The ovarian interstitial tissue was ill developed at neonate stage. While, in adult age it appeared formed of polygonal cells with pale cytoplasm and rounded nuclei. With pregnancy they became hypertrophied with vacuolated cytoplasm and vesicular nuclei. The ovary of lactating female was similar in its histological structure to that of the cyclic one. In conclusion, the present study showed that rabbit ovaries at different physiological conditions had its own characteristic histological features which suit its functional demands. Cytokeratin 7 was found to be represented in the ovarian surface epithelium, all stages of follicular development, oocyte, luteal cells and in the medullary stroma mainly around the blood vessels. So, from this study, it could be recommended that cytokeratin 7 could be used as a tumour marker to distinguish different types of ovarian tumours