The concentration of thiobarbituric acid reactive substances (TBARSs) in plasma and erythrocytes, the activity of selected antioxidant enzymes in erythrocytes: catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx), and the levels of hemoglobin (HGB) and haematocrit (HCT) were determined in 40 patients with sudden sensorineural hearing loss (SSNHL) subjected to 14 treatment sessions in a Haux Starmed 2200 hyperbaric chamber. Hyperbaric oxygen (HBO) therapy involved breathing 100% oxygen at 0.25 MPa. Blood for analysis was collected from the basilic vein at three time points: before the first HBO session, approximately 5 min after the first session, and after the 14th session. The control group included 20 healthy individuals never before treated with HBO therapy. Compared to the pre-HBO values, a 10% increase (P<0.05) in the TBARS concentration in erythrocytes, a 28% increase in the GPx activity (P<0.05), and a 7% decrease in the SOD activity (P<0.05) were observed after 14 HBO sessions. The CAT activity decreased by 6% (P<0.05) after the first session. The TBARS concentration in plasma was 13% higher (P<0.01), while that in erythrocytes was 24% lower (P<0.001) in the SSNHL patients before the first HBO session compared to the control group. The CAT activity in the SSNHL patients before HBO therapy was 26% higher (P<0.001) than that in the control group. A statistically significant reduction in HGB and HCT after 14 HBO sessions (P<0.01) compared to the pre-HBO values was demonstrated. SSNHL is accompanied by disturbance in the oxidant-antioxidant equilibrium. Repeated stimulation with hyperbaric oxygen modulates the activity of antioxidant enzymes. It seems that the increased generation of hydrogen peroxide is responsible for the changes in the activity of antioxidant barrier enzymes observed after HBO sessions.

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The activity of selected antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) in erythrocytes, and the concentration of thiobarbituric acid reactive substances (TBARS) in blood plasma and erythrocytes, were determined in people subjected to hyperbaric oxygen (HBO) therapy due to sudden sensorineural hearing loss (SSNHL). Venous blood samples were taken immediately before entering the hyperbaric chamber and 5 min after leaving it. In the study group, two age subgroups were distinguished: group I consisting of subjects under 35 and group II consisting of subjects over 50. The obtained values were analysed statistically using Student’s t-test. Differences were considered as statistically significant at p < 0.05. A statistically significant decrease in the CAT activity was shown 5 min after leaving the hyperbaric chamber in pooled subjects (p < 0.01) and group I (p < 0.05). Furthermore, a statistically significant decrease in the erythrocyte TBARS concentration was observed in group II (p < 0.05). It was demonstrated that a single exposure to hyperbaric oxygen affects the oxidant-antioxidant equilibrium as evidenced by, e.g., a statistically significant decrease in the activity of catalase in erythrocytes. It is possible that the antioxidant response to HBO depends on the age of subjects.

Objective. To determine the concentration of thiobarbituric acid reactive substances (TBARS) in erythrocytes and blood plasma, and the activities of selected antioxidant enzymes: catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) in erythrocytes in patients receiving hyperbaric oxygen (HBO) treatment due to difficult-to-heal “skin wounds”. Material and Methods. Indices of oxidative stress were assessed in venous blood taken from 23 patients three times: immediately before HBO procedure, approx. 5 minutes after leaving the hyperbaric chamber, and after 25 HBO procedures. Moreover, selected blood counts were measured in the collected material two times: prior to treatment and after 25 HBO procedures. Results. A statistically significant positive correlation between the CAT activity and the TBARS concentration in the erythrocytes of patients was found before treatment in the hyperbaric chamber (r=0.394; P≤0.05). No statistically significant changes in the TBARS concentration in erythrocytes and blood plasma were observed both after the first HBO procedure and after 25 procedures. No statistically significant changes in the activities of CAT, SOD, and GPx were noted. Platelet count decreased by 18.7% (P≤0.05) after 25 HBO procedures. Granulocyte count decreased by approx. 21% (P≤0.05), and granulocyte percentage by 11.8% (P≤0.01). In turn, the percentage of lymphocytes and monocytes increased after the treatment by 16.6% (P<0.05) and 16.4% (P<0.05), respectively. Conclusions. Exposure to HBO due to difficult-to-heal skin wounds does not significantly affect the levels of oxidative stress in the peripheral blood of patients and, from the point of view of oxidation–reduction processes, appears to be a safe therapeutic method for the treatment of chronic wounds.