Features of the right atrium structure in experimental diabetes mellitus and use of antioxidants

Abstract

Right atrium cardiomyocytes were studied in conditions of streptozotocin-induced type 1 diabetes mellitus and with the use of N-acetylcysteine as an antioxidant. The study showed that potential damage of fine mechanisms of synthesis and secretion of atrial natriuretic peptide may be the cause of cardiovascular pathology in diabetes. Use of antioxidant drugs has revealed that N-acetylcysteine partially reduces cardiomyocyte swelling, increases the number of atrial granules containing atrial natriuretic peptide and stimulates autophagy. Based on ultrastructural studies of atrial cardiomyocytes in type 1 diabetes it was found that damage to protein synthesis and accumulation and transformation of abnormal proteins happen via their elimination in two ways: through the ubiquitin-proteasomal and autophago-lysosomal systems. Autophagosomes occur both with a double membrane, i.e. the newly formed one, and with a single membrane after contact with lysosomes. These processes take place to maintain homeostasis in cardiomyocytes and in the myocardium as a whole. Impairement of these systems may lead to development of diabetic cardiomyopathy.