Ultrastructural Analysis of Metanephros Development in Dromedary Camel Fetuses: Insights from Scanning and Transmission Electron Microscopy

Background and Objective: The metanephros, the definitive kidney in mammals, undergoes complex morphogenesis and differentiation during fetal development. Understanding its ultrastructure in dromedary camel fetuses provides insights into renal adaptation in arid environments. The objectives of this investigation were to study the morphology of the metanephros in the camel fetus using standard techniques. Materials and Methods: A total of 73 fetuses (30 males and 43 females) of dromedary camels (Rashaidi, Bishari, and their crosses) their ages ranged between 71 and 426 days were collected from Tambool slaughter point, preserved in standard international fixatives and divided into three groups according to their age. The curved crown-rump length (CVRL) equation Y = 0.366X-23.99 was used to determine the age of the fetus (x) in days from the known (y) CVRL in centimeters. Results: Nephrogenesis in dromedary camel fetuses occurred in the metanephros from 74 to 339 days of age. Ampullae developed from collecting ducts during this period, while podocytes began forming their complex architecture in the first trimester. Distal convoluted tubules differentiated earlier than proximal ones, with the latter developing from the distal tubule’s end. Immature podocytes featured a junctional complex (zonula occludens, zonula adherens, and desmosomes), and the basal lamina showed localized thickening in the nephrons. The metanephros of the dromedary camel fetus is characterized by wide medullae, narrow cortex, long loops of Henle, long proximal and distal tubules, long collecting tubules, and small renal corpuscles. The ratio of the thickness of the cortex to the medulla during the first trimester was 1:1, during the second trimester was 1:1.5, and during the third trimester was 1:4 to 1:5. Rich in blood and nerve supply, thickening of the basal lamina at various locations in the nephrons. Conclusion: The specialized characteristic structures provide the type of adaptation or mechanical support for the cells, particularly during states of dehydration and sudden rehydration resulting from the sudden consumption of large amounts of water.