Comparative assessment of the intestinal microbiota, lipid metabolism and morphological changes of the liver in experimental models of metabolic syndrome

Abstract

Metabolic syndrome (MS) is a widespread polyethiological clustering characterized by metabolic, hormonal disorders and clinical manifestations that significantly increase the risk of developing cardiovascular diseases, atherosclerosis, type II diabetes and other pathological conditions. An important role in the development of MS is assigned to the intestinal microbiota. To develop new therapeutic agents for correction of MS manifestations, it is necessary to develop adequate experimental models. In this paper, comparative studies were conducted to assess the parameters of lipid metabolism, the content of peptide hormones, morphological changes in liver tissue, and the quantitative and generic composition of the intestinal microbiota of mice. Experimental models of experimental hyperlipidemia (HL) caused by the introduction of poloxamer 407 (Pol407) and alimentary MS (a diet with fructose and the addition of cholesterol to the feed) were used. Significant increase in the levels of cholesterol, triglycerides, and low-density lipoprotein (LDL) was found in the group of mice treated with Pol407 injections. To assess the indicators of carbohydrate metabolism in blood serum, the following markers were determined: insulin, adiponectin, leptin. In the alimentary MS model a decrease in adiponectin in the blood serum, while insulin level was increased. In both experimental models, significant changes in the gut microbiota of mice were observed. They were associated with the manifestation of metabolic dysbiosis - an increase in the representation of Firmicutes (staphylococci, streptococci, enterococci) in the biomaterial, changes among representatives of both facultative (E. coli), and transient (Enterobacter bacteria) microflora. In addition, dystrophic, as well as morphological changes and signs of inflammation in the liver tissue were noted in both groups.