RU2252766C1 - Method for preventing toxic action of cadmium in experimental animals in case of chronic intoxication - Google Patents

Abstract

FIELD: ecology, medicine, toxicology, experimental biology.

SUBSTANCE: the present innovation deals with studying the mechanisms to withdraw heavy metals, cadmium, in particular, out of the body in animals and preventing intoxication due to introducing zeolite irlite-1 as 6%-suspension through the probe into animal's stomach at the quantity of 2.5% against body weight simultaneously with daily introduction of cadmium sulfate solution either subcutaneously or through the probe into animal's stomach at the dosage of 0.5 mg/kg.

EFFECT: higher efficiency of prophylaxis.

2 ex, 4 tbl

Description

The invention relates to ecology, medicine, toxicology, experimental biology and can be used to study the mechanisms of excretion of heavy metals, in particular cadmium, from the body.

Cadmium is not a vital trace element for humans, and when it is excessively absorbed into the body, it exerts a pathological effect on various levels of metabolism: for example, at the molecular level, cadmium is able to combine with mercapto groups of various enzymes; disconnect the processes of oxidative phosphorylation; to replace zinc in a number of metallozymes, changing their activity (M.R. Fox, 1976). In a number of studies, the dependence of the exchange of vital electrolytes, in particular calcium, on the toxic effects of cadmium compounds, including at the level of membrane transport, has been identified, the relationship of the pathogenetic effect of cadmium on calcium metabolism with its specific effect on alkaline phosphatase has been identified (N.Yu. Tarasenko et al. ., 1975) and increased excretion of calcium from the body (Kazantis F. et al., 1963; Likutova I.V. et al., 1987). The process of cleansing the body of cadmium is characterized by a very low speed with an effective half-life of 140 ± 20 days; it is released mainly through the digestive tract and kidneys.

Increasing in recent decades, the industrial production and use of cadmium leads to an increase in its level in the environment and the development of severe conditions associated with excessive penetration and accumulation of cadmium in the body. In this regard, there was an urgent need to create and develop methods for preventing the intake and enhancing the elimination of excess cadmium from the body.

Many detoxicants are known that can remove heavy metals from the body. These include thiol compounds - unitiol, succimer, sodium thiosulfate, various complexones - pentacin, disodium salt of ethylenediaminetetraacetic acid, deferoxamine, α-penicillamine, etc. (Mashkovsky M.D. Medicines: in 2 volumes. T.2. - Kharkov: Torsing, 1998. S.212-220). The use, especially long-term, of these synthetic drugs can cause various side effects: gastrointestinal tract disorders, allergic reactions, leukopenia, thrombocytopenia, etc. Also, along with toxins, they are able to remove trace elements from the body and such vital ions as iron, calcium, etc., and cause metabolic disturbances, which complicates their long-term and preventive use.

The attention of many researchers was attracted by natural minerals, unique in their physicochemical properties and breadth of use, zeolites, which are aluminosilicates of alkali and alkaline earth metals. Due to their structure and variety of material composition, they have sorption, ion exchange, and catalytic properties (A.V. Gorbunov et al., 1990; N.I. Petunkin, A.A. Mikhailov et al., 1990; Leach et al., 1990 ) The sorption properties of zeolites are due to the specific open rigid microporous crystalline lattice of the frame type with a special ability to attach and easily remove water without destroying the structure of the mineral. Zeolites can act as an enterosorbent, promoting the excretion of various compounds from the body, such as urea, creatinine, etc., which leads to a decrease in the proportion of substances excreted by the kidneys (A.D. Gerasev et al., 2001), are capable of adsorbing heavy metal salts, have a detoxifying effect on nitrates, nitrites, and mycotoxins (B.A. Timofeev et al., 1981; A.F. Kuznetsov et al., 1992). Due to its ion-exchange properties, zeolites can act as sources of trace elements and ions necessary for the body. So, in the works of researchers (V.V. Bayrakov et al., 1985; N. Herron, 1989; I.D.Tmenov et al., 2000; I.D.Tmenov, B.A. Dzagurov, 2001) it was shown that due to the presence of zeolites in the diet of animals, the digestibility coefficient of calcium, phosphorus, iron, zinc and other ions increases. Zeolites of different deposits have some differences in physicochemical properties and, consequently, in the degree of positive effect. In 1995, in the mountains of the North Caucasus, on the territory of North Ossetia-Alania, a deposit of natural formations was identified, classified as a zeolite, which surpasses previously known zeolites in many respects. They were called Irlites. They later began to distinguish between two types - irlit-1 and irlit-7. We set the task to study the preventive effect of the natural zeolite Irlit-1 on the accumulation of cadmium in animals during chronic intoxication.

The closest is the method (L.N. Gamko, T.A. Talyzina. Natural zeolite as an absorbent of heavy metals in the body of pigs // Zootechny. - 1997. - No. 2. - S.14-16) removal of lead and cadmium from the body pigs using mineral substances - zeolites - in the amount of 4-6% of the diet, which we took as a prototype.

The disadvantage of the prototype is that zeolites are used as feed in the diet, which reduces the accuracy of controlling the dose-dependent effect, and the prophylactic effect of zeolite in chronic intoxication has not been investigated.

The invention is aimed at solving the problem of developing a method for preventing the toxic effects of cadmium in chronic poisoning, including the introduction of natural zeolite irlit-1 simultaneously with the introduction of a solution of cadmium sulfate subcutaneously or intragastrically.

The solution to this problem provides a significant reduction in the toxic effect of cadmium in chronic poisoning by reducing the accumulation and increasing the excretion of heavy metal.

To achieve this technical result, the claimed invention has a method of preventing the toxic effects of cadmium in experimental animals with chronic poisoning, including the introduction of zeolite, has the following significant features: the animals are injected with a natural sorbent zeolite irlit-1 every other day in the form of 6% suspension through a tube into the stomach in an amount of 2 , 5% of body weight simultaneously with the daily administration of a solution of cadmium sulfate subcutaneously or through a tube into the stomach at a dose of 0.5 mg / kg.

The proposed method differs from the prototype, firstly, by the fact that dosed introduction of zeolite irlit-1 is carried out, which facilitates precise control of the dose-dependent effect, and secondly, the simultaneous administration (which means the introduction within the same period - 2 months) of irlit-1 and cadmium sulfate provides a decrease in the accumulation of cadmium in the body and an increase in its excretion.

The prophylactic administration of natural zeolite - irlit-1 in the form of 6% suspension through a tube into the stomach, in an amount of 2.5%, every other day, simultaneously with the introduction of a solution of cadmium sulfate subcutaneously or intragastrally, leads to an increase in the elimination of cadmium from the body through the gastrointestinal tract , a decrease in its content in blood plasma, a decrease in accumulation in the tissues of the liver and kidneys, and a decrease in the pathological effects of heavy metal in experimental animals. The claimed method is effective, cost-effective and easily reproducible.

According to the information available to the authors, the set of essential features characterizing the essence of the claimed invention is not known, which allows us to conclude that the invention meets the criterion of “novelty”.

According to the authors, the essence of the claimed invention should not be obvious to specialists from a known level of medicine, since the above mentioned possibility of obtaining a method for the prevention of the toxic effects of cadmium in experimental animals with chronic poisoning, including the introduction of zeolite - irlit-1 in the form of 6, is not revealed % suspension through a probe into the stomach, every other day, in an amount of 2.5% of body weight simultaneously with the daily administration of a solution of cadmium sulfate subcutaneously or through a probe into the stomach, which allows us to conclude with meeting the criterion of "inventive step".

The set of essential features characterizing the essence of the invention, in principle, can be repeatedly used in medicine to obtain a result consisting in an effective and easily reproducible method of preventing the toxic effects of cadmium by reducing accumulation and increasing its elimination from the body in chronic poisoning, which allows us to conclude compliance of the invention with the criterion of "industrial applicability".

This method is as follows.

To obtain a toxic substance, cadmium sulfate is dissolved in sterile distilled water in such a way that 0.5 mg of cadmium (in terms of metal) falls per unit of solution equal to 1 ml. For every 100 g of rat weight, 0.1 ml of a toxic solution is injected, which is not an excessive water load on the body of the experimental animal. By grinding and dissolving the zeolite Irlit-1 in water, a 6% aqueous suspension is prepared and introduced in an amount of 2.5% of body weight. The cadmium sulfate solution is administered subcutaneously or through a tube into the stomach daily 1 time per day for two months to two groups of animals (No. 1 and No. 2). At the same time, from the first day of the administration of cadmium sulfate to group No. 2, a suspension of zeolite is introduced through the probe into the stomach every other day using a refillable syringe with a specially curved needle on which the probe is worn.

After the experiment (2 months), the cadmium content in the urine and feces was determined in both groups of animals. Rats were killed using thiopental to study the accumulation of cadmium in the liver and kidney tissue, to determine its concentration in blood plasma. The results obtained in group No. 2 were compared with the control (column No. 1) and background indicators of the intact group.

For histological studies, tissue samples (liver, kidney, heart) were fixed in 10% neutral formalin, and then subjected to paraffin filling, followed by preparation of sections 7-8 microns thick. Sections were stained with hematoxylin and eosin. The sections were studied in transmitted light using a Mikmed-1 microscope under a magnification of 80 × 200 × 400.

Example 1. Two groups of male rats (No. 1 control, No. 2) of the Wistar line weighing 200-300 g were injected subcutaneously with a solution of cadmium sulfate at a dose of 0.5 mg / kg every day for two months. Natural zeolite Irlit-1 in the form of 6% suspension in the amount of 2.5% of body weight is introduced through a probe into the stomach of group No. 2 every other day. After 2 months, a study was conducted of the cadmium content in the tissues of the kidneys and liver, its concentration in blood plasma, in urine and feces in two groups of animals. An analysis of the data showed (Table 1; 2) that subcutaneous administration of cadmium sulfate leads to a significant accumulation of heavy metal in the tissues of the liver and kidneys, an increase in its content in blood plasma, urine and feces. However, in group No. 2, against the background of simultaneous administration of irlit-1 clay, significantly lower values of cadmium accumulation in the tissues of the liver (p <0.05) and kidneys (p <0.05), as well as plasma concentrations of this metal ( p <0.05) and urine (p <0.05). Excretion of cadmium with feces in this group becomes higher (p <0.01)

Table 1
The accumulation of cadmium in the tissues of the liver and kidneys with subcutaneous administration of cadmium sulfate at a dose of 0.5 mg / kg. Preventive effect of iritis-1 (M ± m) Groups Kidney, mcg / g Liver, mcg / g BACKGROUND 0.156 ± 0.03 0.466 ± 0.18 No. 1 (CdSO ₄ 0.5 mg / kg 254.7 ± 12.8 452.5 ± 43.7 No. 2 (CdSO ₄ 0.5 mg / kg + iritis) 220.3 ± 10.8 *) 345.3 ± 33.1 *) *) - p relative to experience table 2
The cadmium content in blood plasma, urine and feces with subcutaneous administration of cadmium sulfate at a dose of 0.5 mg / kg Preventive effect of iritis-1 (M ± m) Groups Plasma, μg / ml Urine, soda, mcg / ml Feces
mcg / g BACKGROUND 0.0096 ± 0.002 0.024 ± 0.032 0.406 ± 0.3 No. 1 (CdSO ₄ 0.5 mg / kg 0.619 ± 0.096 2.85 ± 1.02 3.74 ± 1.9 No. 2 (CdSO ₄ 0.5 mg / kg + iritis) 0.397 ± 0.044 *) 0.72 ± 0.24 *) 11.8 ± 1.3 *) *) - p relative to experience

Histological examination revealed alterative and necrobiotic processes in all examined organs. Focal dystrophic and necrobiotic changes in the epithelium of the convoluted tubules were noted in the kidneys. Loosening, mucoid swelling of the membrane structures of the capillary loops of the glomerular glomeruli and Bowman-Shumlyansky capsules and others. In the liver, histostructural changes are presented in the form of focal dystrophic (fatty degeneration) and necrobiotic changes in hepatocytes, Kupffer cells with pronounced discirculatory (plasmapapiative pulmonary pulmonary pulmonitis) in the system of intralobular and portal microcirculation. In the group with the prophylactic administration of iritis-1, pathomorphological changes are much less pronounced, the reaction of immunocompetent tissue to damage to the stromal-vascular structures (hyperplasia of lymphohistiocytic elements, extravasates, endothelial and macrophage activity) is noted.

Example 2. Two groups of male rats (No. 1 control, No. 2) of the Wistar strain weighing 200-300 g were injected through a tube into the stomach with a solution of cadmium sulfate at a dose of 0.5 mg / kg every day for two months. Natural zeolite - Irlit-1 form of 6% suspension in the amount of 2.5% of body weight is introduced through a probe into the stomach of group No. 2 every other day. After 2 months, a study was conducted of the cadmium content in the tissues of the kidneys and liver, its concentration in blood plasma, in urine and feces in two groups of animals. Comparison of the results presented in tables 1; 2, it can be noted that with intragastric administration of cadmium sulfate, the use of irlit-1 significantly reduces the accumulation of cadmium in the liver tissue (p <0.05) and kidneys (p <0.001), as well as the content in blood plasma (p <0.001) and urine (p <0.05). A significant increase in the excretion of cadmium with feces (p <0.02) is noted.

Table 1
The accumulation of cadmium in the tissues of the liver and kidneys with intragastric administration of cadmium sulfate at a dose of 0.5 mg / kg The effect of irlite-1 (M ± m) Groups Bud,
mcg / g Liver,
mcg / g BACKGROUND 0.156 ± 0.03 0.466 ± 0.18 No. 1 (CdSO ₄ 0.5 mg / kg 31.29 ± 1.38 18.14 ± 2.89 No. 2 (CdSO ₄ 0.5 mg / kg + iritis) 19.87 = H, 13 *) 12.7 ± 1.9 *) *) - p relative to experience table 2
The cadmium content in blood plasma, urine and feces with intragastric administration of cadmium sulfate at a dose of 0.5 mg / kg The effect of irlite-1 (M ± m) Groups Plasma; mcg / ml Urine, soda;
mcg / ml Feces;
mcg / g BACKGROUND 0.0096 ± 0.002 0.024 ± 0.032 0.406 ± 0.3 No. 1 (CdSO ₄ 0.5 mg / kg 0.116 ± 0.005 0.605 ± 0.135 9.57 ± 2.7 No. 2 (CdSO ₄ 0.5 mg / kg + iritis) 0.075 ± 0.0017 *) 0.22 ± 0.135 *) 16.2 ± 0.5 *) *) - p relative to experience

Histological studies, as in the first example, revealed a positive effect of the prophylactic administration of iritis-1 during chronic cadmium intoxication, which manifested itself in a much less pronounced degree of dystrophic changes in the nephrothelium of tubular structures, the appearance of restitution sites (complete regeneration) of cortical and medullary nephrothelium, signs active regeneration of endothelium and podocytes (compensatory cell repair). In the liver, moderate fatty degeneration of hepatocytes with signs of their focal regeneration, proliferation and hypertrophy of Kupffer cells, perivascular and stromal lymphoid cell reaction (indicators of immunological activity) were noted.

It can be seen from the foregoing that the prophylactic administration of zeolite - irlit-1 is an effective way to reduce the accumulation and correction of the toxic effect of cadmium in case of chronic poisoning by its compounds.

Claims (1)

A method for the prevention of toxic effects of cadmium in experimental animals with chronic poisoning, including the introduction of zeolite, characterized in that the animals are injected every day with the natural sorbent zeolite Irlit-1 in the form of 6% suspension through a tube into the stomach in an amount of 2.5% of body weight simultaneously with daily the introduction of a solution of cadmium sulfate subcutaneously or through a tube into the stomach at a dose of 0.5 mg / kg