ROLE OF ΚB AND AP-1 TRANSCRIPTION FACTORS IN CHANGES IN NITRIC OXIDE PRODUCTION AND UTILIZATION IN THE HEART OF RATS UNDER CHRONIC FLUORIDE INTOXICATION

Fluorides, being hazardous contaminants of soil and drinking water, can get in excessive amounts into human and animal bodies. This is especially true for regions where the fluoride content in soils is very high, for example, Poltava, Dnipropetrovsk, and Kirovohrad regions in Ukraine. Excessive fluoride intake can change the rate of nitric oxide production. The impact of fluorides on changes in nitric oxide production and metabolism in the heart and the role of redox-sensitive transcription factors in these changes are poorly understood. The aim of this study was to determine the effect of activation of κB transcription factors and activator protein 1 on the activity of inducible NO-synthase, constitutive isoforms of NO-synthase, nitrite and nitrate reductase, arginase, concentration of nitrites, peroxynitrite and nitrosothiols in the heart of rats during chronic fluoride intoxication. Materials and methods. The study was performed on 24 adult male Wistar rats weighing 220-260 grams. Animals were randomly divided into 4 groups of 6 animals in each (control, chronic fluoride intoxication group, κB blockade group and activator protein 1 blockade group). The experiment lasted 30 days. We determined the activity of inducible NO-synthase, constitutive isoforms of NO-synthase, the concentration of peroxynitrite alkali and alkaline earth metals, the concentration of nitrites and nitrosothiols, the activity of nitrite reductase, nitrate reductase and arginase. Results. Chronic fluoride intoxication increases the activity of inducible NO-synthase by 1.74 times, does not affect the activity of constitutive isoforms and reduces the activity of arginase by 35.68% compared with the control group of animals. The concentration of nitrites in the heart of rats increases 1.73 times, peroxynitrite 1.43 times, and the concentration of nitrosothiols doubled. The use of κB transcription factor blockers and activator protein 1 reduces nitric oxide production from NO synthases and reduces the concentrations of all nitric oxide metabolites in the heart of rats under conditions of chronic fluoride intoxication. Conclusions. Activation of κB transcription factors and activator protein 1 during chronic excessive intake of fluoride leads to hyperproduction of nitric oxide in the heart of rats due to increased activity of inducible NO-synthase and nitrite reductases. Excess production of nitric oxide under chronic fluoride intoxication leads to the accumulation of nitrites, peroxynitrite and nitrosothiols in the heart of rats.

Problems of formation of the toxic hepatopathy forming in the conditions of chronic fluoride intoxication of the body

Introduction. Aluminium production is characterized by the accumulation of impurities of various toxic and chemical compositions in the air of working areas, the predominant among which are fluoride compounds. The accumulation of fluorides in the body causes the development of osteoarticular and associated systemic pathology. The aim of the study was to evaluate the hygienic and medico-biological features of toxic liver damage in the conditions of chronic fluoride intoxication of the body. Material and methods. The hygienic working conditions of the workers of the primary professions in aluminium production were evaluated. The analysis of hepatobiliary dysfunction based on clinical and instrumental methods was carried out in 263 subjects with fluoride intoxication and a comparison group of 116 persons. Experimental studies of the morpho-functional liver state in modelling chronic fluoride intoxication were carried out based on toxicological, biochemical, pathomorphological methods with histological analysis of tissues. The toxic properties of sodium fluoride were studied in 117 white laboratory male rats with its peroral route intake into the body. Results. The qualitative composition of the air in the working areas in the electrolysis building was analyzed. The prevalence of pathological disorders of the biliary tract in metallurgists engaged in aluminium production was assessed. Clinical studies revealed a significant prevalence of toxic fluoride hepatopathy, fatty hepatosis, cholecystitis and other disorders in the group of patients with chronic fluoride intoxication. The harmful effect of sodium fluoride on hepatocytes, vessels of the portal tract was shown in an experiment. Hyperfunction of the reticuloendothelial system, Kupffer cell proliferation, irreversible destruction of hepatocytes, necrosis against the background of severe dystrophy, and decreased synthetic activity of the liver were determined. Conclusion. The structure of occupational diseases in the workers engaged in the aluminium production is dominated by hepatobiliary pathology caused by toxic liver damage with fluoride confirmed by experimental data on destructive violations of its morphostructure.

Clinical and experimental studies of the effect of chronic fluoride intoxication on the hormonal status of the body and morphological changes in the thyroid gland

Introduction. The systemic violation of the body's homeostasis under the conditions of the negative impact of production factors scientists determine by the mismatch of neurohumoral mechanisms of regulation of metabolic processes. There are endocrinopathies. They occur with disorganization of the metabolism and violation of the thyroid gland's functional activity with disorganization of the metabolism, infringement of the thyroid gland's available action. The study aimed to learn the nature of endocrine dysfunction, histological changes of the thyroid gland associated with the dynamics of chronic fluoride intoxication of the body. Materials and methods. We analyzed the state of bone tissue and assessed the degree of articular syndrome during the large-scale structural reconstruction of the skeleton in aluminum production workers. The scientists examined the workers using double photon densitometry. The researchers studied the metabolic parameters based on a range of biochemical and instrumental methods. The experiment involved sexually mature male white laboratory rats with a bodyweight of up to 300 grams. We analyzed hormonal status disorders with an assessment of the degree of morphological changes in the thyroid gland. Results. The researchers analyzed the severity of disorders of individual endocrine mechanisms of homeostasis regulation and thyroid morph structure in hyperfluorosis. We treat fluorosis as a polyfunctional pathology. A high proportion of endocrinopathies is a clinical syndrome. It increases the pathological course of chronic fluoride intoxication in workers. We confirm the study with experimental data on metabolic disorders with a persistent toxic effect. We revealed hyperfunction of the thyroid gland against the background of a decrease in glucocorticoid activity, stable electrolyte, and mineral shifts. The researchers conducted an experiment on the late stages of fluoride intoxication. Conclusions. Clinical studies of individuals with chronic fluoride intoxication and concomitant endocrinopathy revealed a significant increase in the number of workers with abdominal obesity, musculoskeletal disorders, mineral metabolism disorders. Also, with deforming osteoarthritis of the joints, osteoalgia against the background of thyroid insufficiency. Experimental data confirm this. The fluorine accumulation in the body causes multidirectional disorders of the hormonal mechanisms of regulation of metabolic processes, alternation of hypo- and hyperfunction changes in the thyroid gland associated with fluoride duration intoxication.

ACTIVITY OF THE MICROSOMAL OXIDATION SYSTEM IN RAT LIVER UNDER THE INFLUENCE OF SODIUM FLUORIDE

Summary. The pathogenesis of fluoride intoxication at the molecular, cellular and functional levels has not been sufficiently studied. There are very few modern data on these issues, so they are contradictory, since the effects of this trace element are multifaceted and cannot be characterized unambiguously. The aim of the study – to learn the state of the monooxygenase system of rat hepatocytes under conditions of the formation of fluoride intoxication. Materials and Methods. In the experiment, we used 30 sexually mature rats (N=30) of the Wistar population weighing 200–210 g for 1.5 months. Sodium fluoride solution was administered orally at doses of 1/10 DL50, which was 20 mg/kg of animal body weight. Results. The results of experiments on the study of oxygen consumption by rat liver microsomes under fluoride intoxication indicated that the rate of endogenous respiration of microsomes, the rate of NADPH oxidation, the rate of NADH oxidation in the presence of EDTA, and the rate of lipid peroxidation increase under the influence of fluorides. Sodium fluoride stimulated an increase in all parameters of microsomal oxidation, except for cytochrome b5. It should be assumed that in this case there is an increase in the generation of reactive oxygen species, free radicals, which stimulate the development of free radical processes in the body and are, most likely, the leading link in oxidative stress. Conclusions. These changes indicate a violation of the bioenergetics of hepatocytes associated with the mitochondrial apparatus and the development of hypoxic processes, which lead to a decrease in the activity of redox reactions occurring at the level of intracellular membranes and organelles.

SUBTOXIC EFFECTS OF SODIUM FLUORIDE ON THE ULTRASTRUCTURE OF PITUITARY GLAND IN RATS

The study aimed at investigating the morphofunctional state of the pituitary gland in white rats under the subtoxic exposure to sodium fluoride. Mature male rats (N = 17), weighing 130-150 g, were intragastrically administered with aqueous solutions of sodium fluoride in a dose of 1/10 LD50 ranged from 20 mg / kg of body weight. The duration of the subacute experiment was 60 days. To assess the morphological rearrangement at the subcellular level of organization of the pituitary gland, electron microscopy was performed. The microscopic study revealed changes in the submicroscopic architecture resulted from dystrophic processes caused by the subtoxic exposure to sodium fluoride. Prolonged sodium fluoride intoxication led to a number of changes in the ultrastructure of the pituitary gland, manifested by the development of intracellular oedema, swelling of mitochondria, changes in the density of their matrix, partial reduction and loss of cristae, vacuolization and expansion of the cisterns of the granular endoplasmic reticulum, an increase in the number of primary lysosomes, in the redistribution of chromatin nucleus and a decrease in the number of ribosomes and glycogen granules. Hemocapillaries showed oedema of endothelial cells, uneven thickening of the basement membrane, vasodilatation with the development of stasis and sludge of erythrocytes. As in the vessels of the hypothalamus, the presence of fibrin and a significant number of platelets has been found. These changes indicate a disruption of bioenergetics associated with the mitochondrial apparatus and the development of hypoxic processes, which lead to a decrease in the activity of redox reactions occurring at the level of intracellular membranes and organelles.

INFLUENCE OF NANOSIZED SILICA OXIDE SUSPENSION ON NITRIC OXIDE PRODUCTION IN RATS TESTES DURING CHRONIC NITRATE-FLUORIDE INTOXICATION

In the Poltava region of Ukraine there is a high possibility of combined excessive intake of nitrates and fluorides, since the waters of the Buchaksʹkii aquifer are rich in fluorine ions, moreover, the Poltava region is a region with a developed agriculture. The purpose of this work is to determine the effect of nanosized silicon oxide suspension on the changes in the activity of nitric oxide cycle components, components, and, namely the total activity of NO-synthases (NOS), the activity of constitutive forms of NOS (cNOS), inducible form of NOS (iNOS), nitrate reductase, nitrite reductase, nitrite reductase, nitrite reductase in the testes of rats under the conditions of chronic combined nitrate-fluorodide intoxication. Materials and methods. The study was conducted on 15 mature male Wistar rats weighing 200-253 g. The animals were randomly divided into 3 groups of 5 animals in each. The first group received daily saline solution through a gastric tube. The second group (chronic combined intoxication group) received sodium nitrate and fluoride in a dosage of 500 mg / kg of sodium nitrate and 10 mg / kg of sodium fluoride. The third group against the background of chronic combined intoxication modelling additionally received a suspension of nanosized silicon oxide is a dosage of 100 mg / kg of active substance. Results. Chronic combined intoxication increases total NOS activity by 65.9% compared to the control group. The increase in NO production by NOS is the result of a 4-fold increase in iNOS activity, since the activity of cNOS under these conditions does not change significantly. Nitrite reductase-dependent NO production increases by 66.7%, nitrate reductase activity increases by 77.8%. Nitrite content in the testes homogenate grows in 2.17 times. Hydrolytic cleavage of L-arginine by arginase increases in 2.88 times. The introduction of nanosized silicon oxide suspension under the conditions of chronic combined intoxication did not statistically significantly change the total NOS activity and cNOS activity compared to the group exposed to chronic intoxication. However, iNOS activity reduces in 3.69 times. Nitrate reductase activity decreases in 1.6 times, while nitrite reductase activity decreases in 45%. The activity of arginases lowered in 2.38 times. The nitrite content of the testes cut down by 23.6%. Conclusions. Chronic combined nitrate-fluoride intoxication leads to the development of hyperproduction of nitric oxide in the testes of rats by activating the inducible isoform of NO synthase and nitrite reductases. The use of nanosized silica suspension during chronic combined intoxication is an effective method to correct nitric oxide overproduction in the testes of rats.

The state of oxidative-antioxidant homeostasis under the influence of subtoxic doses of sodium fluoride

The objective of the study was to study the state of oxidative-antioxidant homeostasis under the conditions of the formation of experimental fluoride intoxication.24 white rats of the Wistar population were daily injected with sodium fluoride solution (20 mg/kg of animal weight). The continuation of intragastric xenobiotic intake was 1.5 months. The control group was monitored for 2 weeks toanalyse their condition. After 2 weeks, and The study program was conducted after 2 weeks when healthy mature (3 months) males weighing 180-200 grams were selected . At the end of the experiment, the control and experimental groups were clogged by decapitation. Evaluation of oxidative-antioxidant homeostasis was doneon the basis of the following indicators: the intensity of biochemiluminescence (BCL) of homogenates of internal organs and blood serum, the blood levels of SH-groups, glutathione, haptoglobin, diene conjugates (DC), malondialdehyde (MDA), cysteine, catalase activity, peroxidase, ceruloplasmine, glutathione peroxidase, superoxide dismutase. Vitamin C was determined in the adrenal glands. Analyzing the effect of fluoride intoxication on the state of oxidative and antioxidant system, it was shown that stimulation of free radical lipid peroxidation, the accumulation of peroxides, hydroperoxides, free radicals and inhibition of the antioxidant system are characteristic in this process. The obtained results confirm that all these mechanisms underlie the formation of structural and metabolic mechanisms of the pathogenesis of fluoride intoxication.