INVESTIGATION OF OXIDATIVE STRESS AND FUNCTION OF MITOCHONDRIA IN MONONUCLEAR LEUKOCYTES OF BLOOD IN PATIENTS WITH CHRONIC BRONCHITIS AND WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE

Aim. This study is devoted to the investigation of indices of oxidative stress and the function of mitochondria of blood mononuclear leukocytes in patients with chronic bronchitis and chronic obstructive pulmonary disease (COPD) with varying degrees of severity of bronchial obstruction. Materials and methods. The study included 50 patients aged 40 to 75 years (median – 67 [61, 70] years), which were divided into 3 groups. The first group included 13 patients with chronic bronchitis. In accordance with the spirometric classification of the severity of obstruction GOLD, the second and third groups included patients with COPD with moderate bronchial obstruction (50% ≤ FEV1 <80%) (n=17) and severe bronchial obstruction (30% ≤ FEV1 <50%) (n=20). In mononuclear leukocytes obtained from patients' blood, the level of oxidative modification of proteins, antioxidant protection parameters (superoxide dismutase activity) and bioenergetic function of mitochondria (succinate concentration and succinate dehydrogenase activity) were studied. Results. In comparison with the indicators of patients with chronic bronchitis in patients with COPD in mononuclear leukocytes, reliable and significantly less activity of superoxide dismutase and a significantly higher level of spontaneous oxidative modification of proteins are determined. Patients with COPD with severe bronchial obstruction have a significantly lower reserve-adaptation potential of oxidative modification of proteins compared with patients with moderate bronchial obstruction. It was established that in patients with COPD in blood mononuclear leukocytes, statistically significantly lower succinate dehydrogenase activity and succinate concentration were observed comparison with patients with chronic bronchitis. Conclusion. In patients with COPD, the prerequisites for the development of mitochondrial dysfunction of mononuclear leukocytes caused by the development of oxidative stress are created, which is reflected in a statistically significant decrease in the activity of superoxide dismutase and an increase in the degree of oxidative modification of proteins compared with those of patients with chronic bronchitis. In patients with chronic obstructive pulmonary disease with severe bronchial obstruction, a statistically significant reduction in the reserve-adaptive potential of oxidative modification of proteins was revealed than in patients with COPD with moderate bronchial obstruction. Chronic obstructive pulmonary disease is accompanied by the development of mitochondrial dysfunction of blood mononuclear leukocytes, which is expressed by a decrease in the activity of succinate dehydrogenase and a decrease in succinate concentration in comparison with those of patients with chronic bronchitis.