The impact of grape pomace extract rich in natural complex of polyphenols on morpho-functional state of leukocytes under experimental diabetes mellitus

Abstract

Background. Diabetes mellitus is one of the most common diseases in the world. Under this pathology all organs and systems of an organism are damaged, inclu­ding the immune system. Peripheral blood leukocytes are an important element of this system that suffer damage under diabetes mellitus due to the influence of reactive oxygen species and reactive nitrogen species, the number of which increases fast and leads to the development of oxidative-nitrative stress. Thus, the discovery of new diabetes-correcting drugs that possess hypoglycemic, antioxidant and immunomodulatory proper­ties is one of the principal tasks. Such properties are inherent in polyphenolic compounds, a large amount of which is contained in the grape pomace. That is why the study of grape pomace extract, rich in a natural complex of polyphenols, is important to evaluate the possibility of further use of these substances as a basis for drugs that can be used in the complex therapy of diabetes mellitus. Materials and Methods. The research used peripheral blood leukocytes of the control rats, the control animals that were treated with grape pomace extract for 14 days, animals with streptozotocin-induced diabetes mellitus and rats with experimental diabetes mellitus that were treated with grape pomace extract for 14 days. To evaluate the corrective effect of the grape pomace extract rich in a natural complex of polyphenols on the state of the antioxidant defense and the L-arginine/NO systems, the activity of antioxidant enzymes, the level of oxidative modification products of proteins and lipids, the activity of NO-synthase, the content of nitrites and nitrates, 3ʹ-nitrotyrosine-modified proteins were studied. The total number of leukocytes, the white blood cell differential and the phagocytic activity, and the average cytochemical coefficients of cationic proteins and NADPH-oxidase activity were indicated to study the effect of the grape pomace extract on the functional state of leukocytes. Results and Discussion. The study revealed normalization of the total number of leukocytes and the white blood cell differential, the activity of NADPH-oxidase, superoxide dismutase, catalase and glutathione peroxidase, and the levels of the oxidative modification products of proteins and lipids, nitrites, nitrates and 3ʹ-nitrotyrosine-modified proteins, as well as an increase in the average cytochemical coefficient of cationic proteins, and a decrease of the inducible NO-synthase activity after grape pomace extract administration for 14 days to animals with streptozotocin-induced diabetes mellitus. Conclusion. The obtained results confirm the antioxidant and immunomodulatory effects of the studied extract and justify the feasibility of using grape pomace complex of polyphenolic compounds as a basis for new drugs that will be used in the complex therapy of diabetes mellitus.