Evaluation of selected morphofunctional changes in the myocardium in experimental diabetes mellitus

The article presents the results of a study on morphofunctional changes in the myocardium and the degree of their severity in the context of experimental diabetes mellitus. The authors used a streptozotocininduced diabetes model, which develops after a single intraperitoneal injection of an experimentally determined diabetogenic dose. A comprehensive analysis was conducted of the structural changes in cardiomyocytes, connective tissue, and vascular components under experimental diabetes mellitus. Histological, morphometric, and immunohistochemical examinations of the myocardium were performed in Wistar rats, and the results were statistically evaluated. The study revealed that under the modeled pathology, cardiomyocytes undergo significant morphofunctional changes, expressed in particular by a decrease in the nucleus-to-cytoplasm ratio. Streptozotocin-induced diabetes led to the accumulation of lipid peroxidation products in the myocardium, accompanied by a reduction in the activity of antioxidant defense enzymes. There was a significant increase in the volume density of collagen fibers in the interstitial and perivascular spaces, resulting in fibrosis development. An increase in the Kernohan index demonstrated changes in the vascular wall: thickening of the media and a reduction in the inner diameter of blood vessels led to impaired tissue oxygenation in the myocardium. The morphofunctional changes in the myocardium observed under experimental diabetes mellitus indicate a shift of adaptive-compensatory processes toward decompensation and the development of myocardial dystrophy.