Morphological changes in the parenchymal organs of rats under conditions of the combined effect of metallotoxicosis against the background of immobilization stress and the corrective role of melatonin

Abstract

to establish the features of morphological and ultrastructural changes in the liver and kidney tissues of rats under conditions of combined action of aluminum and lead salts, immobilization stress, and to evaluate the protective effect of melatonin on these processes. Experimental studies were carried out on 5 groups of mature white male rats, where 14-day intoxication with aluminum and lead compounds, 1-hour immobilization stress, and pineal gland hypofunction under 24-hour lighting conditions were modeled; the analysis was performed using light and electron microscopy. It was found that the combined effect of toxic factors and stress causes deep destruction of the vascular bed, endothelium desquamation, disorganization of organ parenchyma in the form of granular, hydropic, and fatty degeneration, as well as focal necrosis of hepatocytes; at the ultrastructural level in the kidneys, local thickening of the glomerular basement membrane and degradation of mitochondria in endotheliocytes were recorded. Hypofunction of the pineal gland significantly aggravates the pathomorphological picture, while the use of exogenous melatonin demonstrated a pronounced cytoprotective and reparative effect, which is confirmed by a decrease in the intensity of dystrophic changes and activation of proliferation of renal tubular epithelial cells.