Comparative Histology and Histometry of the Renal Capsule in Dromedary She Camel (Camelus dromedarius), Cow (Bos indicus) and Ewe (Ovis aires)

Abstract

Kidneys from adult she camels, cows and ewes (eight from each) were investigated using histologic and histometric techniques to study the renal capsule. The capsule in the kidney of the three species was made up of two layers, outer and inner. The outer layer of the renal capsule was composed mainly of dense collagenous fibres arranged in wavy bundles. The outer layer was the thicker in she camel (396 µm) as compared to cow (39 µm) and ewe (36 µm). The outer layer represented about 82% of the total thickness of the capsule in she camel and cow whereas it was only 37% in ewe. The inner layer in the three species was mainly formed of smooth muscle fibers, and fine collagen and reticular fibres. The reticular fibres in the inner layer of the renal capsule were markedly extensive in ewe and cow compared to she camel. Smooth muscle fibres formed a distinct thick layer in ewe and a thin one in cow; however, in her camel they were randomly distributed. No elastic fibres were present in all capsules studied. The inner layer was observed to be thick in ewe as it constituted about 63% (61.2 µm) of the total thickness of the capsule compared to only 18% in both cow (8.4 µm) and she camel (84.3 µm). The study revealed that the renal capsule was thickest in she camel (480.4 µm) compared to ewe (97.5 µm) and cow (47.3 µm). It is concluded that the renal capsules of she camel, cow and ewe showed remarkable variation in thickness as well as the amount of the histological components. It is suggested that such variation might influence the function of the renal capsule.