State of lipid peroxidation and antioxidant defense in blood and liver in the process of correcting the negative effects of fluoride (experimental studies)
Authors:   Danylo Halytsky Lviv National Medical University, Fedorenko Yu.V. 
Published: November 2024

Objective. To investigate the dynamics of changes in lipid peroxidation and antioxidant defense in blood and liver tissue under conditions of fluoride exposure before and during biological correction. Materials and methods. In the experimental conditions, 4 series of experiments were conducted on mature white Wistar rats weighing 170-200 g, which were administered an aqueous solution of sodium fluoride at a dose of 10 mg/kg of body weight daily for 30 days, separately and with consistent addition of bioprotectors to the animals’ food. In the first series of experiments, fluoride was administered without bioprotectors, in the second series – with pectin, in the third – pectin and calcium, in the fourth – a complex of pectin, calcium and antioxidants – vitamins C, E, β-carotene, selenium. Animals in the control groups were given drinking water and supplemented with appropriate bioprotectors. The content of diene conjugates, malondialdehyde, superoxide dismutase activity, catalase activity, and antioxidant activity index were determined in blood and liver tissue. The integral coefficient characterizing the antioxidant state of the organism was calculated based on the ratios of the activity of antioxidant defense and the intensity of lipid peroxidation processes. Results. It was found that during the experiment, the level of lipid peroxidation products was increased: diene conjugates in the blood by 168% on day 15 of the experiment, in the liver by 29.8%, on day 30 – in the blood by 36.2%, in the liver by 86.5%, malondialdehyde in the blood by 25.0%-53.0%, in the liver by 27.9%-41.7%, respectively, compared to the control group. Meanwhile, in both periods of observation, the activity of superoxide dismutase increased in the blood by 31.4%-46.0%, in liver tissue by 35.2%-75.2%, catalase activity decreased to a greater extent in the blood by 29.2%-51.4%, in liver tissue by 24.1% to 28.2% compared to the control group. The obtained results indicate an increase in oxidative stress in the dynamics of fluoride intoxication, which is confirmed by the low values of the integral coefficients. Pectin practically did not contribute to the improvement of antioxidant defense under conditions of prolonged fluoride intake. The addition of calcium with pectin to the diet of animals significantly improved the course of metabolic processes in the lipid peroxidation-antioxidant defense system. In the liver tissue, lipid peroxidation indicators were recorded at the control level, while in the blood the level of diene conjugates remained high, malondialdehyde exceeded the control values by 27.8%, and antioxidant defense was low. The enzymatic link of antioxidant defense was more active than the non-enzymatic link, with an antioxidant activity index lower by 31.7% compared to the control group. Calcium ions bind fluoride ions to form a hardly soluble calcium fluoride compound in the digestive tract, which inhibits fluoride absorption in the intestines and fluoride intake in the blood. Thanks to pectin, calcium fluoride can be excreted from the body. The addition of antioxidants to the diet of animals normalized the studied indicators of lipid peroxidation and the activity of superoxide dismutase and catalase in liver tissue, the integral coefficients were also almost at or close to the control level. Antioxidant defense is more active in liver tissue than in blood. Conclusions. Sodium fluoride caused oxidative stress in the test animals. The addition of pectin, calcium, vitamins C, E, β-carotene and selenium to the diet of the laboratory animals simultaneously activates metabolic processes, establishes a balance in the lipid peroxidation system - antioxidant defense of blood and liver tissue and can be used to correct antioxidant defense under conditions of negative fluoride exposure. Keywords. Sodium fluoride, blood, liver tissue, conjugated dienes, malondialdehyde, superoxide dismutase, catalase, bioprotectors.