Prenatal metanephrogenesis of the camel: morphological evidence of epithelial-mesenchymal interaction

Differential expression of epithelial and smooth muscle lineage-specific markers of metanephros in one-humped camel foetuses

The development of the metanephros in one-humped camels involves a complex series of interactions between epithelial and mesenchymal cells. As a result, there is a synchronized differentiation process of stromal, vascular and epithelial cell types during glomerulogenesis, angiogenesis and tubulogenesis. In the current work, the metanephros of camel foetuses were divided into four stages where kidneys from each stage were processed and immunoassayed, followed by quantitative analysis to determine target protein intensities throughout metanephrogenesis in the camel. This study demonstrated robust expression of α-smooth muscle actin (α-SMA) in the glomerular mesangium, as well as in interlobular and glomerular arterioles during the earlier stages of development. However, in the late stages, α-SMA expression became more localized around the blood capillaries in both the cortex and medulla. Strong expression of CD34 was observed in the immature glomerular and peritubular endothelial cells within the subcapsular zone, as well as in the glomerular, proximal tubular and distal tubular epithelium of stage one foetuses, although its expression gradually diminished with foetal maturation. The expression pattern of osteopontin was prominently observed in the distal convoluted tubules throughout all stages, however, no expression was detected in the proximal tubules, glomeruli and arterioles. E-cadherin was detected in the developing renal tubular epithelial cells but not in the glomeruli. In conclusion, this study reveals the spatiotemporal distribution of key proteins, including α-SMA, CD34, Osteopontin and E-cadherin, which play a crucial role in metanephrogenesis in camel foetuses.

Scanning electron microscopy and morphometric analysis of superficial corneal epithelial cells in dromedary camel (Camelus dromedarius)

It is likely that superficial corneal epithelial cells (SCECs) of the dromedary camels have a significant role in their survival at arid and semiarid regions. To the best of our knowledge, SCECs of camels' eyes have not been characterized previously using scanning electron microscopy (SEM), combined with morphometric analysis. Therefore, in the current study, we aim to describe the shape, topographical distribution, and density of SCECs associated with morphometric analysis using SEM. Twelve healthy adult camels' corneas were obtained immediately after slaughter. Each cornea has been divided into nine parts: central (C), middle dorsal (MD), middle ventral (MV), middle nasal (MN), middle temporal (MT), peripheral dorsal (PD), peripheral ventral (PV), peripheral nasal (PN), and peripheral temporal (PT). SCECs were distinguished and characterized into light, medium, and dark mosaics. The polygonal cells have been externally covered with microplicae that were more numerous above the light cells. The topographic distribution of light, medium, and dark cells revealed a well-defined concentration of light cells in excess of other cells in all parts as follows: PV (92.5%), PN (78.5%), MN (78%), MT (74.7%), PD (73.8%), PT (70.7%), MV (68.7%), MD (66.3%), and C (19.3%). The PV part recorded the highest density of light cells, while the C portion showed the lowest density for the same cells. We concluded that the light cells extensively predominate in all parts of the camels' cornea except the C part, indicating an adaptive modification to the harsh environment. Additionally, the PV and PN parts represent the permanent and endogenous source as well as a proliferative reserve for SCECs in dromedary camel.

Survey of nuclear progesterone receptor expression in the uterus of the cyclic and pregnant camel (Camelus dromedarius)

Progesterone receptors (PR) are necessary to mediate the biological effects of progesterone and are integral to the regulation of a number of different aspects of reproduction in mammals including ovulation of the oocyte, implantation of the conceptus and maintenance of pregnancy. This study investigated the expression and localization of progesterone receptors in the uterine wall of both pregnant and cyclic (nonpregnant) camels. Uterine tissue samples were collected from healthy animals and processed for routine histological and immunohistochemical staining techniques to reveal nuclear PR. Demonstration of PR was performed by indirect immunohistochemical techniques using monoclonal antibodies raised against human PR. Immunolocalization of PR was more intense in all four endometrial zones (I-IV) as well as the myometrium of non pregnant (cyclic) animals (animals with newly formed corpus luteum). In contrast, PR immunostaining in both the endometrium and the myometrium was greatly reduced in pregnancy, particularly in the latest stage examined (approximately 366 days of gestation). In conclusion, a better understanding of the expression of steroid hormones and their receptors, including progesterone and the PR is critical to improving the reproductive health and pregnancy in the domesticated dromedary camel.