Background: Oxidative stress is the main cause of mortality in chemical burn-induced esophageal injury. Melanin, a natural antioxidant compound from yeast-like fungus Nadsoniella nigra strain X- 1, has been shown to decrease the content of lipid peroxidation products after burn. The aim of this study was to investigate the protective effect of melanin in the treatment of esophageal injury after a chemical burn. Methods: A alkali burn model was used to induce injury to the esophagus in immature rats. Changes in the levels of malondialdehyde, secondary products of lipid peroxidation (thiobarbituric acid reactive substances), superoxidase dismutase, and catalase in the blood, as well as changes in the esophagus tissue, were examined. Results: Melanin decreased the content of lipid peroxidation products following burn injury. Melanin increased the activity of superoxidase dismutase and reduced the activity of catalase, as well as reduced esophagus oxidative injury in our chemical burn model. Conclusion: Melanin treatment may protect against chemical burninduced esophageal injury, possibly by inhibiting burn-induced oxidative stress.

Abstract-Exogenous poisoning with alkalis takes the leading position among causes of acute poisoning. Esophageal burns as a result of accidental swallowing of caustic material are seen frequently in children ages 1 to 8 years. A burn wound is perhaps the most intense stress that a human body can suffer. In the place of chemical trauma localization the processes of synthesis and degradation of proteins increase. As a result the structure and functions of vital organs and immune system suffer. The inflammation process after burn injury is determines the changes in protein expression. In our research we have shown that chemical burn of the esophagus is characterized by decreased level of total proteolytic activity, total protein and development of endogenous intoxication of the body as indicated by elevated MMM level. Obtained results suggest that the development of chemical burns of the esophagus grade 2 is characterized by more substantial changes in the protein composition of blood compared with grade 1. An in-depth study of this disease has a crucial scientific and practical importance for development of pathogenically oriented methods of wound process healing after the chemical esophageal burns depending on the stage and extent of the burn process.

Introduction: As a result of alkaline substances entering the esophagus wall, necrosis occurs, as well as destruction of the mucous, submucosal and muscular layers of the esophagus. The cellular immune system plays an important role in regulating the various phases of the wound healing process, during which, depending on the time and through specific adhesion interactions, polymorphonuclear leukocytes, macrophages, and lymphocytes penetrate the site of the trauma and lead to an intensive proliferation of fibroblasts, endothelial cells, and keratinocytes. The substances of natural origins based on polyphenolic compounds are possible as a remedy for the normalization of physiological and biochemical parameters in a condition of various pathologies. Phaseolus vulgaris pods extract (PVPE) are an example of a rich source of bioactive compounds with proven human health benefits. Our results revealed imbalance of pro-inflammatory and anti-inflammatory cytokines in esophageal homogenates in rats with alkali burn of esophagus II degree, which can indicate a prolonged inflammation in the burned area. In the groups of animals with the alkaline burn of the esophagus, that were injected extract there can be traced a change of the indicators in the direction of normalization, indicating about the therapeutic effect of aqueous extract of pods of Phaseolus vulgaris. Objective: The cellular immune system plays an important role in regulating the various phases of the wound healing process, and can be used as a marker of pathological post-burn wound healing, Phaseolus vulgaris pods extract (PVPE) are an example of a rich source of bioactive compounds with proven human health benefits. The aim of the study was to investigate changes in cytokines levels in rat esophageal supernatants in the condition of alkali burn esophagus second degree (AEB 2) and treatment with Phaseolus vulgaris pods extract. Material and Methods: The animals were experimentally simulated with the alkali esophageal burn with 20% (grade II) solvent of NaOH. Levels of cytokines in esophageal tissue homogenates were done by ELISA. Results: In the present study, we investigate the imbalance of pro-inflammatory and anti-inflammatory cytokines in esophageal homogenates in rats with AEB 2, which can indicate a prolonged inflammation in the burned area. In the groups of animals with the AEB 2, that were injected extract there can be traced a change of the indicators in the direction of normalization. Conclusion: The administration of the extract, in conditions of alkaline burn of the esophagus, contributes change of the indicators in the direction of normalization indicating the therapeutic effect of aqueous extract of pods of Phaseolus vulgaris.

Caustic esophageal burns are among serious medical problems of global significance. Due to a key role in biological processes proteolytic enzymes actively involved in the pathological mechanisms underpinning the development and progression of burn-related complications. Since melanin possesses a broad spectrum of biological activities we have investigated whether this compound can influence the proteolytic activity and level of proteinase inhibitors in the blood of rats with an alkali esophageal burn. Alkaline esophageal burns, which correspond to the first and second degree of burn, were induced by 10% and 20% NaOH, respectively. White, nonlinear, immature (4 weeks old) rats were used in the experiment. Total proteolytic activity was measured using casein as a substrate. The activities of α1- antitrypsin and α2-macroglobulin were measured considering the degree of inhibition of hydrolysis of N-benzoyl-L-arginineethyl ester. The fraction of serine proteinases was obtained by affinity chromatography on a benzamidine sepharose column. The qualitative composition of serine proteinases fraction was analyzed by zymography technique. According to the data obtained, the pathogenesis of alkaline esophageal burn is accompanied by a significant increase in the total proteolytic activity, activity of serine proteinases, and activity of α1-antitrypsin and α2-macroglobulin compared with the control rats. The present results clearly indicated that melanin is able to normalize the proteolytic homeostasis by affecting the activity of serine proteinases and the level of proteinase inhibitors in the plasma of rats with alkali esophageal burns.