COPD is a heterogeneous disease with multiple clinical phenotypes. COPD endotypes can be determined by different expressions of hypoxia-inducible factors (HIFs), which, in combination with individual susceptibility and environmental factors, may cause predominant airway or vascular changes in the lung. The pulmonary vascular phenotype is relatively rare among COPD patients and characterised by out-of-proportion pulmonary hypertension (PH) and low diffusing capacity of the lung for carbon monoxide, but only mild-to-moderate airway obstruction. Its histologic feature, severe remodelling of the small pulmonary arteries, can be mediated by HIF-2 overexpression in experimental PH models. HIF-2 is not only involved in the vascular remodelling but also in the parenchyma destruction. Endothelial cells from human emphysema lungs express reduced HIF-2α levels, and the deletion of pulmonary endothelialHif-2α leads to emphysema in mice. This means that both upregulation and downregulation of HIF-2 have adverse effects and that HIF-2 may represent a molecular “switch” between the development of the vascular and airway phenotypes in COPD. The mechanisms of HIF-2 dysregulation in the lung are only partly understood. HIF-2 levels may be controlled by NAD(P)H oxidasesviairon- and redox-dependent mechanisms. A better understanding of these mechanisms may lead to the development of new therapeutic targets.

To study the effect of microbial proteases on the activity of matrix metalloproteinases and oxidative stress indicators in wound tissue of rats with experimental diabetes mellitus (DM). Methods. Skin burns were induced in the animals without somatic pathology and with the background diabetes mellitus. DM was reproduced by a single injection of streptozotocin, 50 mg/kg. The multi-enzyme proteolytic composition Pronase (Sigma-Aldrich, USA), obtained from the culture fluid of Streptomiceus griseus, was applied to the wound. The content of malonic dialdehyde (MDA), as well as the activities of catalase (CAT), superoxide dismutase (SOD), and glutathione (GSH) were measured on a spectrophotometer. The collagenolytic activity of matrix metalloproteinases (MMPs) of skin tissues was determined by enzymephoresis (gelatin zymography). Results. At the physiological wound healing, an application of the composition increased the activity of total MMPs in homogenate on days 3-14 of the healing process, which enhanced the formation of free radicals and the activity of antioxidant system to compensate tissue damage. Thus, the CAT, GSH and SOD levels were elevated on days 7, 14 and 21, respectively. In case of DM, an application of the composition enhanced the activity of MMPs on days 14-21, which improved the proteolytic degradation of extracellular matrix proteins in the state of excessive glycation and did not worsen oxidative homeostasis state in the wound. Conclusion. The use of exogenous proteases is appropriate to enhance proteolysis in tissues with predominance of glycated proteins in case of chronic hyperglycemia to ensure controlled proteolysis. K e y w o r d s: streptozotocin-induced diabetes, burn wounds, oxidative stress, proteolysis, healing.

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Relevance. The risk of developing of diabetic foot ulcers is 25% over the lifetime of patients with diabetes mellitus. Inhibition of wound healing is associated with impaired macrophage polarization, decreased bioavailability of growth factors, enhanced activation of matrix metalloproteinases, which in turn is probably associated with severity of not only oxidative stress, but also nitrosative one. Objective. To investigate the indices of nitrosative stress in connective tissue regeneration in the healing of burn wound in rats with simulated diabetes, compared with rats without diabetes. Materials and methods. Two groups of laboratory rats of the Wistar line were used: diabetes mellitus and thermal burns were simulated in the experimental group (n=24), and only burns were modelled in the control group (n=24).  Diabetes mellitus was reproduced by administering of streptozotocin at a dose of 50 mg/kg to rats of the experimental group.  Thermal burns with a total area of ​​18-20% of the body surface were reproduced by applying of copper plates heated in water to 100°C to the skin of rats.  Animals were removed from the experiment by decapitation under thiopental anesthesia, 6 rats of each group at a time on 3, 7, 14 and 21 day of observation.  Concentration of inducible NO-synthase (iNOS), 3-nitrotyrosine proteins and vascular endothelial growth factor (VEGF) were measured in tissue regenerate samples by Western-blot analysis.  The content of malondialdehyde (MDA) was determined in the blood serum of rats by reaction with thiobarbituric acid and subsequent spectrophotometric analysis.  The measured values ​​are expressed in arbitrary optical density units (arbitrary units, a.u.). Results. The expression of inducible NO-synthase (iNOS) was shown to be significantly decreased during burn wound healing in diabetes mellitus compared with controls at 7 and 14 day of burn wound healing.  Thus, iNOS level was 1.24±0.05 a.u. in the control group and 0.72±0.03 a.u. in the experimental one at 7 day of observation; 0.93±0.08 a.u. and 0.32 ± 0.02 a.u., respectively, at 14 day.  Statistically significant differences in the level of 3-nitrotyrosine compounds between the control and experimental groups were detected only at 3 day of observation: 1.0±0.05 and 0.69±0.04 a.u., respectively.  The level of malondialdehyde (MDA) increased significantly in the experimental group from 3 to 14 day of observation, from 0.77±0.01 a.u.  to 8.17±0.07 a.u., which indicates the severity of lipid peroxidation in diabetes.  A statistically significant difference in MDA levels between the control and experimental groups was observed at all observation periods: from 4.13±0.09 and 0.77±0.01 a.u., respectively, at 3 day of observation to 4.18±0.09 and 3,46±0.25 a.u., respectively, at 21 day.  A positive correlation between the level of malondialdehyde and 3-nitrotyrosine compounds (R=0.647; р<0.05) in diabetes mellitus is described, while in the non-diabetic group, it was negative (R=-0.528, p<0.05).  A decrease in the level of VEGF in tissue regeneration samples in diabetes mellitus was found compared with the control group at 3, 7 and 21 days of observation, which correlated with impaired expression of iNOS (R=-0.703; p<0.05) in diabetes mellitus. Thus, at 3 day of observation, VEGF level was 1.0±0.06 a.u. in the control group and 0.4±0.03 a.u. in the experimental group; on 7 day - 2.76±0.05 and 1.46±0.08 a.u., respectively;  on 21day  - 2.61±0.09 and 1.26±0.06 a.u., respectively. Conclusions. It is shown that in diabetes mellitus during healing of the burn wound, there is a local decrease in the level of iNOS expression, which leads to inhibition of NO formation and its physiological effects. Increased oxidative stress, while further reducing the bioavailability of NO through the formation of peroxynitrite. One of the important effects of NO during wound healing is the enhancement of VEGF formation. Shown reduction of NO (due to the reduced expression of iNOS) is correlated with the decrease of VEGF level in tissue regeneration in diabetes, which is one of the important factors of impaired wound healing.

The microelements, closely linked to enzymes, vitamins and hormones, cause the metabolic transformations to realize the genetic potential of the productivity in pigs. The use of chelate compounds of microelements as an alternative replacement of mineral salts allows to increase their conversion, to reduce the content in compound feeds, preventing environmental pollution. The purpose of the study was to determine the effect of microelement lactates on prooxidant-antioxidant homeostasis in boars. It was used the adult boars of the Large White breed in the study. The duration of the experiment was 120 days, including: preparatory one is 30 days, basic one is 60 days (feeding boars with zinc, selenium, copper and iron lactates) and the final one is 30 days. In the main period of the experiment, the diet of the animals in the control group remained unchanged, and the two experimental ones were with the addition of zinc, selenium, copper and iron. The level of biologically active components in the diet of the study groups was higher by 10 % and 20 % compared with the control group. In the obtained blood samples it has been determined the state of the prooxidant-antioxidant state. Feeding zinc, selenium, copper and iron lactates in the feed mixture for boars significantly changes the prooxidant-antioxidant state in the blood depending on the amount of micronutrients additionally fed. The addition of these biologically active substances by 10 % above normal after 60 days of feeding helps to preserve the content of vitamins antioxidant action, restored glutathione, stimulates the functional activity of superoxide dismutase by 50 % and catalase by 23.6 % and is accompanied by a slight decrease processes of peroxidation decreasing the concentration of conjugates and TBA-active complexes. The addition of the microelement lactates to the feed mixture by 20 % more than the norma for boars compared with the control group after 30 days of the consumption stimulates the processes of peroxidation, accompanied by intensive use of non-enzymatic – vitamin A (P < 0.05–0.01) and the activation of enzymatic antioxidants – superoxide dismutase (P < 0.05–0.01) and catalase, which lasts for 90 days.