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

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