Aspects of development of bone marrow in male albino rats: Light and electron microscope study

Twenty five healthy male albino rats were utilized in this study to throw more light on the histological and ultra structural changes in femur's bone marrow at different ages in albino rats. They were classified into five groups [5 animals each]: group A, [prenatal, 17-19 days of gestation], group B [newborn, I-day old], group C [one week old], group D [adult, 3-6 months old], and group E [senile, more than I8-months old]. The animals were sacrificed and small pieces of femurs were taken and processed for light and electron microscopes examination. The bone marrow was consisted of vascular and non vascular elements. The vascular elements of the prenatal group showed small capillaries and many dilated blood sinusoids. They were lined with flat endothelial cells with little cytoplasm. Large cells[adventitial cells] with large nuclei, pale cytoplasm and long processes were noticed on the abluminal side of dilated sinusoids in the marrow of the newborn. The marrow arterioles of 1 week- old and adult groups were lined with cuboidal lining cells and surrounded by pericytes with flat nuclei and long processes. However, in the senile group, multiple thick walled arterioles with narrow lumen were detected. The non vascular elements of the marrow were formed of hemopoietic and non hemopoietic cells. In the prenatal group, some cells showed small electron dense nuclei, dense cytoplasm and irregular cell membrane [apoptotic cells]. Many large macrophages with eccentric nuclei were seen in cIose relation with the apoptotic cells. Giant cells with multiple nuclei and vacuolated cytoplasm [osteoclasts] were noticed adjacent to calcified spicules. Many hemopoietic cells at different stages of development were noticed at 1-day of age. Apoptotic neutrophils with dark nuclei and muddy cytoplasmin together with mitotic cells were also observed. Hemopoietic cells were markedly increased at the age of I-week, adult, till senile. Fat cells and many megakaryocytes were also marked. The megakaryocytes appeared as large cells with multilobulated nuclei and numerous electron dense granules in their cytoplasm. Also, intracytoplasmic canaliculi appeared as elongated vesicles which may branch. These canaliculi were of smooth surface and enclosed empty cores. With senility, there was marrow hypocellularity. Most of the cells were apoptotic. In conclusion, bone marrow started its function as a hemopoietic organ postnatally. In senile group apoptosis predominated mitosis. Predominance of mitosis in young ages making them more recommended as a potent source for bone marrow transplantation

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 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

Histological study of the taste buds of the circumvallate papilla in the tongue of male albino rat in different ages

Twenty male albino rats were utilized in this study to investigate the histological, and ultrastructural modification in the circumvallate papillae of male albino rat with special attention to the development of taste bud during prenatal, postnatal development and aging. The animals were divided into five groups [four animals each] according to the their age Group A prenatal animals [18-19 day of gestation] group B [0 day old] group C [2 week old, group D [adult 5-7 months] and group E senile [18-24 months]. The animals were anaesthetized using ether inhalation, their tongues were dissected immediately and processed for light and electron microscope examinations. The circumvallate papilla of the prenatal group was dome shaped elevation covered with non keratinized stratified squamous epithelium and surrounded by a closed furrow from both sides, No taste buds were observed. In 0 day old rats the circumvallate papilla was surrounded by a partially obliterated furrow and the papillary wall was lined by immature taste buds, formed of few clusters of dark and light cells without taste pore. Their nuclei were found at the apical and basal poles of the buds, also unmyelinated nerve fibers were detected between these cells. By the age of two weeks the circumvallate papilla was surrounded by an opened furrow which lined by immature taste bud without taste pore. Many light cells and some dark cells were noticed on the apical and basal pole of the buds. In addition unmyelinated nerve fibers were detected between taste cells. In adult group, the circumvallate papilla was surrounded by an opened furrow and its wall was lined by many mature taste buds with taste pores. Each task bud was formed of elongated cells, that converge at the taste pore, their nuclei occupied the basal half of the bud. The taste bud was formed of dark, light, intermediate and basal cells. The dark cells were small irregular in their outline with electron dense cytoplasm and nuclei. They extended cytoplasmic processes that separated and surrounded the other taste cells and intragemmal nerve fibers. The apical part of these cells contained dense secretory granules. The light cells were larger than dark cells and contained large smooth outline oval. They were characterized by electron lucent vesiculated cytoplasm. The intermediate cells were less common type of cells found in the adult rat taste buds. They were found to share characteristic of both light and dark cells and their cytoplasm were moderate in electron density between light and dark cells. In senile group, the circumvallate taste buds were formed from few elongated cells that converge at the taste pore and their nuclei occupied the basal half of the bud. Each taste bud was formed of dark and light cells. The dark cells were the commonest cell type and they were small irregular in outline with electron dense cytoplasm and nuclei. Few light cells with electron lucent cytoplasm and large oval nuclei Unmyelinated nerve fibers were observed between these cells. It become clear that the peripheral gustatory system was maintained histologically over a wide age range. Thus the change in the taste acuity reported in old age may be due to histological or biochemical changes in the taste cells

Histological study of age related changes in the non-gustatory portion of the tongue in male albino rats

Twenty male albino rats were utilized in this study to investigate the histological and ultrastructural changes that occur during morphogenesis of the filiform papillae in the rat. The animals were divided into five groups [four animals each] according to their age. Group A [18-19 day of gestation], group B [0 day - old] group C [2 week old], group D [5-7 months] and group E [18-24 months]. The animals were anaesthetized using ether inhalation, their tongue were removed immediately and processed for light and electron microscope examination. The dorsal surface of the tongue of the prenatal group is covered with the rudiments of the filiform papillae; they were rounded elevation covered by 4-5 layers of epithelial cells with no evidence of keratinization. Scanty collagen fibers appeared in between the lingual muscles. In the 0 day old rat, the filiform papillae were rounded, however a keratinization layer was clearly visible on the tip of each filiform papillae. The distributions of collagen fibers were few in between the lingual muscles and below the mucosa of dorsal surface. In the 2 weeks old rats the filiform papillae on the anterior part of the tongue were conical with pointed tips and covered by a thick keratin layers. Its epithelium was differentiating into anterior and posterior cells columns. The anterior cell column was formed of several layers of flattened epithelial cells. Their cytoplasm were fined with many keratohyaline granules of different size and shapes and few tonofilaments. The cells of the posterior column were elongated with oval nuclei. The cells in this layer were fined with large number of tonofibrils in both the deep and the shallow intermediate layers. Some collagen fibers were increased in between the lingual muscle fibers and in the lamina propria and connective tissue core of the papillae. In the adult group the filiform papillae on the anterior part of the tongue were compactly distributed. They were long, slender and covered by a thick keratin layer. Its epithelium was differentiated into anterior cell column and the posterior cell columns of the filiform papillae and interpapillary cell columns contained keratohyaline granules. Many collagen fibers were increased between the lingual muscle fibers and in connective tissues underlying the papillae. In the senile animals the filiform papillae were less distributed on the dorsal surface of the tongue. They were conical in shape with pointed tips. Their epithelium differentiated into anterior cell columns of filiform papillae fined with many keratohyaline granules and posterior cell columns fined with tonofibrils. The interpapillary cell columns appeared wide and their superficial cells were fined with many keratohyaline granules of different sizes and shapes. Extensive distribution of the collagen fibers in the lamina propria and in the connective tissue core of the papillae. These results indicate that, in rat the morphgenesis of filiform papillae was advanced in parallel with keratinization of the lingual epithelium from the stage just before birth to a stage a few weeks after birth. In senile group the collagen fibers were increased in lamina propria and connective tissue of filiform papillae. These changes affect the distribution and function of these papillae

Light and electron microscope study of albino rat testis at different ages

Forty male albino rats were used to study the histological picture of testis at different age groups. They were classified into three groups; prepubertal [20 rats divided equally into two subgroups: A [7 days], and B [21 days]], adult [10 rats, 3-4 months] and senile [10 rats, 16-18 months]. After anesthesia, small pieces of testes were dissected and processed for light and electron microscope study. In rats aged 7 days, the testis showed seminiferous cords lined by spermatogonia and Sertoli cells. Large rounded, pale-stained gonocytes occupied their centers. The cords were surrounded by more than one layer of myoid cells. Leydig cells were small and found in clusters. Their cytoplasm showed many lipid droplets and mitochondria with disrupted cristae. At 21 days of postnatal life, most cords turned into tubules lined by spermatogonia, spermatocytes and Sertoli cells, whereas, apoptotic gonocytes appeared towards the adluminal side. Tight junctions began to appear on cell membrane of Sertoli cells. In the adult group, the seminiferous tubules were lined by stratified germinal epithelium with spermatids at different stages of development and surrounded by a single layer of flattened myoid cells. Inter-Sertoli tight junctions divided the tubules into basal and adluminal compartments. Leydig cells had oval nuclei and their cytoplasm showed sER. mitochondria, few lipid droplets of variable sizes. In old aged rats, there were wide interstitial spaces. Some tubules showed wide lumina and reduced epithelial lining. They were surrounded by thickened irregular basement membrane. Germ cells of such tubules showed pyknotic nuclei and wide intercellular spaces. Sperms had highly attenuated darkly stained head, and malformed tail. Sertoli cells showed large lysosomes and vacuoles. Leydig cells appeared with irregular nuclei and their cytoplasm showed many lipid droplets and vacuoles. It could be concluded that the two extremities of age have adverse effects on fertility in males. Giving birth at senility for good generations is in doubt

Light and electron [SEM and TEM] microscope study of the fourth ventricle ependymal lining in rabbit

The ependymal structure of the floor of the fourth ventricle of adult rabbit was investigated using light, scanning and transmission electron microscopy. Eight adult healthy male rabbits were anaesthetized with ether and sacrificed. Small pieces of the floor of fourth ventricle were taken. They were processed for preparation of paraffin sections, stained with Hx and E and examined by L/M. Other minute pieces of them were processed for scanning and transmission electron microscope study. The ependymal cells of the fourth ventricle were seen forming a single row of cuboidal cells with prominent rounded nuclei. Scanning electron microscope showed that the floor of the fourth ventricle exhibited different zones separated by prominent grooves. The ependymal cells exhibited a dense netweek of long cilia. These cilia gradually decreased towards the median sulcus where the ependymal cells were devoid of cilia, but instead they had microvilli on their luminal surfaces. Also pit-like holes appeared in the ependymal lining along the median sulcus, globular supra-ependymal surface projections were noticed. The transmission electron microscope showed that the cells apart from the median sulcus had long and profuse network of interwoven microvilli and cilia over their luminal surface. The cell bodies exhibited supranuelear Golgi complexes, few electron dense granules and multivesiculated bodies. These features suggested a secretory and/or absorptive role

Histological and histochemical studies on the effect of alloxan induced diabetes on the skeletal muscles of the rabbit

The present work deals with the histological and histochemical changes in the rabbit gastrocnemius muscle fibers due to alloxan induced diabetes. Thirty healthy male New Zealand rabbits were utilized. The rabbits were divided into two groups; The Animals of the control group [ten rabbits] were injected singly with sterile saline [1 mI/kg body weight] in their ear veins. Each animal of the experimental diabetic group [twenty animals] was injected with a single dose of Alloxan [100 mg dissolved in 1 mI sterile saline/kg body weight] in 1 st ear vein to induce diabetes. The experimental group was further subdivided into two subgroups; [a] Subgroups B: were sacrificed 8 weeks after Alloxan injection. 1b] Subgroup B: they were sacrificed 16 weeks after Alloxan injection. Specimens from gastrocnemius muscles of all animals were prepared for histochemical staining. Other specimens were also prepared for transmission electron microscope examination. The collagen fibers between the muscle fibers were increased in diabetic animals. Electron microscopy revealed a marked decrease in the number of mitochondria, the cristae of which were also diminished or oven lost, moreover, the electron-dense granules in the mitochondrial matrix were increased. Thickening of the basement membrane of the muscle capillaries was also noticed in the diabetic animals. Regarding the histochemical changes of the muscle fibers of diabetic animals; it was found that the glycogen content of these fibers was deceased, while the lipid content was unchanged. The activities of both, Alkaline phosphatase and Acid phosphatase enzymes were increased, but the activity of Succinc dehydrogenase enzyme was markedly diminished. No changes could be detected in the activity of Adenosine triphosphatase enzyme in the diabetic muscle fibers. This work concluded that diabetes mellitus has serious effects of the muscle fibers affecting mainly the mitochondria and the oxidative enzymes resulting in weak contractility and rapid fatigue of the muscles