Morphological features of white adipose tissue in rats with different levels of energy metabolism in visceral obesity

Histomorphological changes of visceral white adipose tissue in obesity as a function of the level of energy metabolism in the body have not been sufficiently studied. The aim of this study was to investigate and compare the structural changes of visceral white adipose tissue in rats with different metabolic levels and severe visceral obesity. The study was carried out on male Wistar rats aged 3 months at the start of the experiment. Control animals received standard diet. Experimental rats were fed a high calorie diet for 12 weeks. At the end of the experiment, rats from both the control and experimental groups were divided into low and high level of energy metabolism depending on the intensity of total oxygen consumption. Histological preparations of visceral white adipose tissue were prepared according to the standard method. Histomorphometry was performed on digital images using the “Image J 1.34p” computer program. Biochemical methods were used to determine the concentration of triglycerides, lipids and cholesterol in blood serum. The method of multifrequency bioimpedance was used to assess the biophysical properties of visceral white adipose tissue. The data obtained were processed by methods of variational statistics using one-way analysis of variance. It was shown that long-term use of a high-calorie diet led to the development of visceral obesity, which was manifested by a significant increase in the weight of visceral fat and an increase in the concentration of indicators of lipid metabolism in blood serum. It was found that a high-calorie diet altered the morphological structure of the rat’s visceral white adipose tissue, leading to adipocyte hypertrophy, reduced blood volume and increased the amount of connective tissue in it. The bioelectrical properties of the visceral white adipose tissue changed, as evidenced by an increase in its electrical impedance and a decrease in its frequency dispersion coefficient. The intensity of structural, biochemical and biophysical changes in the visceral white adipose tissue was more pronounced in rats with low level of energy metabolism and depended on the degree of obesity. The results obtained are important for practical medicine in the development of new effective methods for the prevention and treatment of obesity in patients according to level of energy metabolism.