INFLUENCE OF ESTROGENES ON THE OXIDATIVE-ANTIOXIDANT SYSTEM OF LIMBIC SYSTEM OF THE BRAIN

The aging process is accompanied with changes in hormonal balance and the reorganization of the functional brain systems. Substantiation of the topic. With age there is an increase in the formation of free radicals, which provokes multiple dysfunction of signaling pathways. The toxic effect of free radicals is accompanied by a decrease in the activity of antioxidant enzymes. Such changes are a necessary biochemical component of neurodegenerative diseases. The inhibition of estrogen by chronic oxidative stress protects the neuron from mitochondrial dysfunction and inhibits cell aging. Menopause in older women has a definite influence on the prevalence of diabetes mellitus, and chronic hyperglycemia is involved in the pathogenesis of oxidative stress. The purpose of the study was to investigate the influence of sex hormones on the state of the prooxidative antioxidant system in ovariectomized, elderly, and rats with experimental diabetes mellitus. Materials and methods. The study was conducted on 40 sexually mature female rats of 4-5 months and 20 months old. Animals were divided into several groups: a control group of 4-5 months, the study groups: 4-5 month ovariectomized, and with experimental diabetes mellitus, and a group of old rats, and with experimental diabetes. Ovariectomy was performed using the method of Y.M. Shynka. Experimental type 2 diabetes mellitus was reproduced by intramuscular administration of 15 mg / kg of protamine sulphate twice daily for 2 weeks. The content of diene conjugates (DK) and malonic aldehyde (MA) was determined for the evaluation of the intensity of peroxide oxidation of lipids in the homogenates of the brain structures under investigation (the fields of the hippocampus CA1, CA2, CA3). The state of antioxidant protection was assessed by the activity of superoxide dismutase (SOD), catalase (KT) and glutathione peroxidase (GPO). Results and discussion. Ovariectomy caused an increase in the levels of lipid peroxidation and decreased activity of antioxidant enzymes in all areas of the hippocampus, with the predominance of these processes in the field of CA3, which is consistent with the literature data on structural changes that are expressed in decreasing the density of the location of neurocytes and degenerative structural changes. The tendency to increase peroxidation was maintained against the backdrop of developing diabetes mellitus. The results of the study of the influence of age on the reduction of estrogen levels on the background of diabetes indicate an extinction of the oxidative-antioxidant system and indicate a transition to a lower level of functioning, in conditions of impaired blood supply and reduced oxygen supply. Conclusions. The increase in peroxidation after ovariectomy and the age-related decrease in estrogen is due to the antioxidant effect of hormones, which depends on the ability of estradiol to stimulate cellular antioxidant enzymes. The combination of ovariectomy, age, and diabetes is accompanied by an increase in lipid peroxidation and a decrease in antioxidant defense. The combination of age-related changes in enhanced peroxidation and the reduction of antioxidant defense against the background of diabetes mellitus is accompanied by depletion of the prooxidation-antioxidant system.