Nefodova О. О., Аzarov О. І., Harets V. I., Kuznetsova O. V., Zhitniy M. I., Shevchenko I. V. Malchuhin R. K.

MORPHOLOGY

Scentific article

Abstract. Exposure to cadmium compounds leads of serious adverse effects on human health, which include severe diseases of the reproductive system, the development of the cardiovascular system, kidneys and liver. In the process of metabolism in humans and animals, final products are formed, which, accumulating in the body, can cause poisoning.In this regard, their removal is one of the fundamental and vital functions of the body, violation of which leads to incompatible with life consequences.The main part of this function is accounted for by the urinary system, which, in addition, removes excess water, salts and xenobiotics from the body. The purpose of the presented experimental study is an analysis of the results of chronic effects of cadmium salts (chloride/citrate) on the development of the kidneys of rat embryos when administered intragastrically to females throughout pregnancy. In addition to the control group, there were 2 groups of isolated administration of cadmium (chloride/citrate) at a dose of 1.0 mg/kg of body weight of the female and 6 groups of combined administration of cadmium salts with metal citrates:cerium (1.3 mg/kg), zinc (1.5 mg/kg), iron (1.5 mg/kg).The cadmium chloride solution had an ionic form.In our experimental models we used solutions of cadmium, iron, cerium and zinc citrates obtained by aquananotechnological methods.The test solutions were administered to pregnant females from the first day of pregnancy daily intragastrically (by probing).The results of the effect of the studied substances on embryos were evaluated after euthanasia of females under anesthesia of sodium thiopental on the 13th and 20th day of pregnancy and on the 10th day of postnatal development of rats.The kidneys of embryos and rats were subjected to histological examination.A ZEISS Axiocam ERc 5s light microscopy camera with a P95-C 1/2 «0.5x adapter connected to a ZEISS Primo Star microscope was used to obtain digital images and then calculate the dimensions of the structures.To determine the possible nephrotoxic effect of the test agents on histological specimens, the average values were calculated according to the following data: renal mass (mg), M ± m; the thickness of the renal cortex (μg), M ± m; the thickness of the cerebral substance of the kidney (μg), M ± m; diameter of the glomerulus of the nephron (μm), M ± m; the area of the glomerulus of the nephron, (μm), M ± m. Analysis of the effect of cadmium salts on the development of the kidneys of 13-day-old embryos showed that, despite the same doses of cadmium chloride and cadmium citrate, the changes in nephrogenesis were clearly different.Exposure to cadmium chloride led to an increase in mesonephros and mesonephric duct, and exposure to cadmium citrate reduced the studied parameters.In the groups of combined administration of cadmium salts with iron, zinc and cerium citrates, the nephrotoxic manifestations of cadmium at this time were significantly reduced, which was manifested in the reproduction of mesonephros and duct thickness to sizes close to control values. Examining the renal parenchymal zonation of 20-day-old embryos, we calculated the ratio of the cerebral cortex (thickness, μm) to the cortical to exclude errors associated with changes in weight in the experimental groups.It is proved that the increase in body weight in the group exposed to cadmium chloride was due to an increase in the thickness of the brain substance and the cortical layer of the kidney embryos,while when exposed to cadmium citrate, the thickness of the cortical part increased insignificantly compared to the control, and the thickness of the cerebral layer decreased insignificantly.The calculation of the above indicators in the form of the ratio of the thickness of the cerebral layer to the cortical is a clear proof of the degree of developmental disorders of the developing parenchyma of the developing kidneys.The calculation of this ratio in the control group is – 2.59, while the effect of cadmium chloride reduces the ratio to 2.21, although the weight of the kidney increases.At isolated introduction of cadmium citrate, despite decrease in average indicators of weight of body, the ratio is equal – 2,26, that is the indicator is closer to control values.Thus, the obtained indicators indicate a different degree of kidney damage when exposed to the same doses of different cadmium salts.The following dynamics of the ratio was determined in the groups of combined introduction of cadmium salts with citrates of the investigated metals.In the groups of combined administration with cadmium chloride, the highest degree of restoration of zonation of the embryonic kidney parenchyma was observed to 2.46 in the group with iron citrate, 2.42 – with cerium citrate and 2.37 with zinc citrate.That is, the highest compensatory qualities of nephrotoxicity of cadmium chloride has iron citrate when combined in an experiment on rats.In the groups of combined administration with cadmium citrate the closest to the control was the ratio of the layers of the renal parenchyma of 20-day-old embryos in the group with a combination of cerium citrate – 2.44, and in the groups with zinc citrate and iron citrate this figure reached 2.39. Despite the lower degree of nephrotoxicity of cadmium citrate, the level of compensatory reaction with the studied biometals was lower. The effect of cadmium salts led to a decrease in the diameter of the renal corpuscle and the area of the cavity of the capsule of the nephrons,but the studied parameters of nephrogenesis determined a lower level of nephrotoxic cadmium citrate compared to cadmium chloride, despite the identity of the dose of exposure.In the groups of combined administration of cadmium with cerium, zinc and iron citrates, a decrease in the nephrotoxic effect of cadmium on the studied parameters was determined,which allows us to consider metal citrates as bioantogonists of cadmium in these doses in an experiment on rats

rat embryo, kidney, cadmium, iron citrate, zinc citrate, cerium citrate

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«Bulletin of problems biology and medicine» Issue 1 (159), 2021 year, 224-230 pages, index UDK 616.61:591.3:546.48:612.6

10.29254/2077-4214-2021-1-159-224-230