Postnatal development of the albino rat renal cortex [histological study]

Renal development involves 2 basic processes: morphologic formation and acquisition of function. The aim of the present study was to obtain histological information about the postnatal development of the filtration barrier and to throw more light upon the concomitant developmental changes of the convoluted tubules in albino rat's renal cortex. Ten pregnant female rats were utilized. Fifteen of their off springs were taken and divided into 3 groups: Group A: studied at the 2[nd] day postnatal. Group B: studied at the 10[th] day postnatal. Group C: studied at the 21[st] day postnatal. Kidneys were removed then 5 micro m thick paraffin sections were obtained and stained with haematoxylin and eosin stain for light microscope study. Renal cortex was cut into minute pieces and prepared for electron microscope study. Light microscope examination of 2 days renal cortex exhibited two cortical zones. The subcapsular zone contained immature forms of the renal developmental stages; the juxtamedullary zone contained mature renal corpuscles. While, electron microscope examination showed podocytes with flat cytoplasmic sheets and foot processes. Endothelial cells had few fenestrations. The filtration barriers revealed double basement membrane. The lining cells of proximal tubules had few short apical microvilli, mitochondria randomly oriented and few basal infoldings. Also, those of distal convoluted tubules appeared with randomly oriented mitochondria and some basal infoldings. The light microscope examination of 10 days renal cortex showed disappearance of all immature forms and maturing glomeruli were observed. Electron microscope examination showed podocytes with its primary processes and foot processes. The endothelial cells showed numerous fenestrations. The filtration barriers revealed fused basement membranes with presence of outpockets. The lining cells of proximal tubules had numerous tall tightly packed apical microvilli. Mitochondria appeared lodged in the basal infoldings in both proximal and distal tubules. The light microscope examination of 21 days renal cortex revealed mature renal corpuscles with lobulated glomeruli. Electron microscope examination demonstrated mature glomeruli showing podocytes with numerous foot processes. The filtration barrier showed regular basement membrane with no outpockets. The endothelial cells appeared attenuated with numerous fenestrations. Proximal and distal tubules showed mature picture. It has been proposed that adult renal diseases may be determined by events that occurred during fetal development. Therefore, results of studies on renal development in experimental models need to be interpreted and correlated carefully with the concomitant functional changes

role of hormone replacement therapy on structural integrity of lacrimal gland in ovariectomized albino rats [histological and immunohistochemical study]

Sex steroid hormones are important regulators of lacrimal gland functions. In addition, dry eye syndrome is conmion in menopausal women. This work was conducted to demonstrate the role of hormone replacement therapy [HRT] on structural integrity of the lacrimal gland of ovariectomized rats. Thirty six adult female albino rats, were used in the present work divided into three equal groups: Group I [control] and group II [bilaterally ovariectomized rats] sacrificed 1 and 12 weeks following ovariectomy. The third group contained ovariectomized rats receiving HRT was subdivided into: Subgroup lila received estradiol benzoate and subgroup III b received androgen. Small pieces of the gland were obtained and processed for different histological and immunohistochernical stains. One week after ovariectomy the connective tissue septa was thickened. Collagen fibers were abundant with extensive cellular infiltration around dilated ducts and congested blood vessels. Some acinar cells were vacuolated and others contained darkly stained nuclei. Twelve weeks after ovarictomy, the acini were lined with low cuboidal cells and their lumina were widened with increased collagen fibers inbetween. In hormone treated group, the gland nearly regained its normal architecture, however few acinar cell nuclei showed hyperchrornatism. In estrogen treated group some interlobular septa were widened. Concerning fiRs inimunoreactivity, in group 11, the acinar cell nuclei showed strong positive reaction in the first week then the reaction was negative after 12 weeks. The immune reaction for ERs remained negative after the HRT. One week after ovariectomy, the immune reaction for bcl-2 was weak in the cytoplasm of ductal cells and moderate in interstitial cells. After 12 weeks, they became immune negative and after estrogen and androgen treatment marked rise in their bcl-2 immune reactivity was observed. Sex hormone balance was proved to be a crucial factor in maintaining structural and functional integrity of lacrirnal gland. So, future clinical therapeutic strategies based on estrogen and/or androgen replacement therapy for aged women and patients with premature ovarian failure could help in preventing or curing dry eye syndrome associated with lacrimal deficiency is adivsed

Immunohistochemical and ultrastructural assessment of folliculostellate cells in rabbit pituitary gland at different ages

This study was performed on nine male Balady rabbits classified into three groups [three animals each]; young [3-months old], adult [6-8 months old] and old [20-months old]. At the time of scarification, the pituitary glands were dissected and processed for light and electron microscopy examinations. The immunohistochemical reaction to S-100 protein revealed a significant decline in the localization of the folliculostellate [FS] cells positively immunolabelled in the pars distalis of the old rabbit pituitary compared with the young and adult animals. By electron microscope, FS cells were found with clear cytoplasm, devoid of secretory granules and had long narrow processes, that intermingled with neighboring cells. They appeared in a close contact with all types of secretory cells, especially gonadotrophs. Cellular junctions sealed were detected either between the FS and hormone- secreting cells or linking two FS cells. Adult rabbit anterior pituitary showed FS cells with prominent RER. Many FS cells from the old rabbit pituitary showed dispersed heterochromatic nuclei and distorted mitochondria, vacuolated cytoplasm were often seen with numerous microvilli on their borders. Remarkable changes appeared with age in the different types of endocrine cells including vacuolated cytoplasm and dilated granular endoplasmic reticulum