SUMMARY
Introduction. In recent years, there has been an increase in the prevalence of gastroesophageal reflux disease and autoimmune thyroiditis in young people. This is associated with a hereditary predisposition, viral diseases, which are often recorded in children's and adolescent groups, the unreasonable use of a large number of drugs, as well as the influence of various negative environmental factors, instability of the autonomic nervous system, eating disorders, the presence of bad habits, chronic stress and others. The aim of the work was to investigate the state of total antioxidant status and the content of biomarkers of the second phase of detoxification of xenobiotics - manganese superoxide dismutase and glutathione peroxidase in young people with gastroesophageal reflux disease and autoimmune thyroiditis. Materials and methods. To achieve this goal, 120 patients with a combined course of gastroesophageal reflux disease (GERD) and autoimmune thyroiditis (AIT) were examined, which made up the main group and two comparison groups: with isolated GERD (45 people) and AIT (42 patients). All patients were students of various universities and were between the ages of 18 and 25. Duration of the disease did not exceed 3 years. The total antioxidant status as an indicator of the first phase of defense and the levels of mitochondrial manganese superoxide dismutase and glutathione peroxidase – the second phase of antioxidant defense was determined. Results. The study showed that in all surveyed groups there was a decrease of total antioxidant status, which characterizes the first phase of the antioxidant defense system. Changes in the first phase of antioxidant defense affect the indicators of the second level of the system, which became the basis for studying the activity of mitochondrial manganese superoxide dismutase. Thus, the value of this indicator in all examined individuals exceeded the norm, which confirmed the inclusion of the second controlling phase of antioxidant system into the pathological process. At the same time, an increase inhibition of the glutathione defense link, the second phase of xenobiotic detoxification, were diagnosed. Conclusions. Negative changes occur in the enzyme system of the first line of antioxidant system in patients with GERD and AIT which may be the result of an unfavorable autoimmune background. Control over the work of antioxidant system moves to the second phase of the system, manifested by an increase in the content of mitochondrial manganese superoxide dismutase and inhibition of the activity of glutathione peroxidase in patients with a combination of GERD and AIT.