Basement membranes in the kidney of the dromedary camel (Camelus dromedarius): An immunohistochemical and ultrastructural study

Abstract

Basement membranes consist of various proteins, the major ones being laminin and collagen type IV. Primary defects in these two proteins have been extensively associated with kidney pathologies. This study aimed to establish baseline information on the immunohistochemical distribution of laminin and collagen type IV, and to corelate these with the ultrastructure of basal laminae in the uriniferous tubules of the dromedary camel. Tissue samples were taken from the kidneys of eight adult female camels, and processed for immunohistochemical and ultrastructural investigations. Strong intensity of collagen type IV was observed within the basement membranes of Bowman’s capsule. The thickness of the basal lamina of the parietal layer of Bowman's capsule varied extensively depending on the region of the renal corpuscle; the thicker areas were always associated with cuboidal epithelial cells. The glomerular basement membrane revealed strong immunostaining of laminin, whereas the mesangial matrix was strongly immunoreactive to collagen type IV. Abundant amount of laminin was found in the basement membranes of proximal convoluted tubules, thin limbs of the loop of Henle, and collecting ducts. Dense immunostainings of laminin and collagen type IV were observed in the medullary regions of uriniferous tubule, in which numerous projections extended from the basal laminae into the subjacent connective tissue. Overall, the present study revealed marked variations in the distribution of the basement membrane markers laminin and collagen type IV in the uriniferous tubules of camel kidney. The results have also shown difference in the thickness of basal laminae. This variation in thickness, however, was unlikely to be influenced by the amount of laminin and collagen type IV.