Histological structure of the kidneys of South Ural sheep in the postnatal period of ontogenesis at six, eighteen and thirty-six months

The purpose of research is to study the features of the histological structure of the kidneys in sheep of the South Ural breed in the postnatal period of ontogenesis. The material for the study was the kidneys of sheep of the South Ural breed from 18 individuals of both sexes, delivered from the household plot of Baymukhambetov K.T. in the Orenburg Region. Animals were divided into 3 age groups based on the classification of periods of development. The study was conducted in the conditions of the Department of Morphology of Physiology and Pathology of the Orenburg State Agrarian University. For histological examination, the material was taken no later than two to three hours after the slaughter of the animal. Pieces of tissue were fixed in 10 % neutral formalin solution. After fixation and compaction, the pieces were embedded in paraffin. Histological sections 5-7 µm thick were stained with hematoxylin-eosin. On histological preparations, the thickness of the connective tissue capsule, cortex and medulla of the organ, the diameter of superficial, intracortical and juxtamedullary nephrons, as well as the diameter of the vessels of the microvasculature of the kidneys were determined. Morphometric parameters were obtained using a screw eyepiece-micrometer MOV-1-15x (GOST 15150-69) and an eyepiece ruler, followed by statistical processing of quantitative parameters of histological structures. Analyzing the morphometric data of the studied postnatal period of ontogenesis, we can conclude that there is an active process of increasing the linear parameters of the structural and functional tissue components of the kidneys up to six months of age; in general. The dynamics of morphometric parameters of adult animals from one and a half to three years is less significant. By the age of six months, the processes of completion of nephron histogenesis in the subcapsular zone are noted, probably stimulated by the process of weaning (3 months) of lambs and complete transition to solid food, as well as the formation of a specific micromorphology of the organ, which indirectly indicates the formation of the function of the organ. In the studied sex and age groups, the wave-like dynamics of morphometric parameters and the absence of pronounced qualitative changes indicate the full morphological maturity of the organ.