Metabolic disorders induced the changes in the expressions of TNFα, E-cadherin and ultrastructural alteration of liver cells in a typical animal model of type 2 diabetes: Psammomys obesus.

By using a unique animal model of type 2 diabetes mellitus, Psammomys obesus induced by a high-calorie diet (HCD) for nine months, we showed for the first time, in the liver, the impact of inflammation on the remodeling of intercellular junction molecules E-cadherins during the progression of steatohepatitis. Under the effect of HCD, the expressions of immunohistochemical markers, Tumor Necrosis Factor alpha (TNFα) and E-cadherins were inversely correlated. Ultrastructural examination revealed the involvement of destabilization and loss of E-cadherins in the process of hepatic pathogenesis. This mechanical maintenance stress was favored by the recruitment of immune cells which contributed to the triggering and progression of fibrosis by the enlargement of the intercellular space and the invasion of collagen fibers. Furthermore to escape cell death, loss of E-cadherins played a major role in mediating fibrosis. Psammomys obesus is a promising model for experimental research, enabling the extrapolation of observed structural and functional alterations in humans, the objective to find new therapeutic targets. The physiological resemblance between Psammomys obesus and humans enhances the precision and relevance of biomedical research efforts.

Light and electron microscopic studies of the Gerbillus tarabuli (Thomas, 1902) Harderian gland.

The purpose of this investigation was to study the morphological aspects of the Harderian gland in Gerbillus tarabuli. Tissues were obtained from both male and female adult Gerbillus tarabuli and processed for light and electron microscopy. The Harderian gland in gerbil is large and well developed, covered by a thin capsule, from which thin septae extend, subdividing the gland into lobes and lobules. The endpieces of the gland are tubuloalveolar, which produce a secretion of lipid character. The glandular epithelium is pseudostratified with two types of secretory cells, the type C cells are columnar in shape with large lipid vacuoles, and type P cells pyramidal and serous, they are basally located with no luminal aspect. The epithelium possesses well-developed myoepithelial cells. The wide lumina are filled with lipid vacuoles, cellular debris, and porphyrins. The Harderian gland of the gerbil has no morphologically distinct duct system; a single extraglandular excretory duct is detected. Electron microscopic examination revealed that type C cells contain large electron-light lipid vacuoles, a well and extensive reticulum endoplasmic and a large number of mitochondria. The pyramidal cells are characterized by a small number of PAS-positive granules at the basal region; these cells exhibit one or two round nuclei, many electron-dense granules, crystalloid bodies, abundant mitochondria and many ribosomes in their cytoplasm. The three mechanism of secretion are seen in the Harderian gland of Gerbillus tarabuli. In its overall characteristics, the Harderian gland of Gerbillus tarabuli conforms to the general pattern observed in rodents. However, further research will be needed to correlate the presence of cytoplasmic slashes, crystalloids bodies and glycoproteins in epithelial cells with the biology of these animals and to their functional significance.