Effect of carnosine and α-lipoic acid on hepatocyte apoptosis and the cytokine profile in induced fatty liver disease in Wistar rats

Abstract

Non-alcoholic fatty liver disease (NAFLD) is now a common liver disease affecting about a third of the world's population. In this regard, the issue of studying the pathogenetic factors of the development of this disease in order to select adequate drug therapy and biologically active substances with antioxidant properties regulating the balance of pro- and anti-inflammatory cytokines is of particular relevance. The aim of the study was to assess the effect of minor biologically active substances - carnosine and α-lipoic acid on hepatocyte apoptosis and the cytokine profile in the experimental model of the initial stage of NAFLD. Material and methods. The studies were performed on male Wistar rats with initial body weight of 150±10 g. Animals were divided into 5 groups of 8 rats each. Within 8 weeks, rats of the 1st group (control) received a complete modified diet AIN93M, in which soybean oil was replaced with sunflower oil and lard (1:1). Rats of the experimental groups consumed high-calorie choline-deficient diet (HCCDD), in which fat content was 45%, fructose content - 20% of the energy value of the diet. Rats of the 2nd group were fed HCCDD without any supplements, the 3rd group - with the addition of carnosine (75 mg/kg body weight), the 4th group - with the addition of α-lipoic acid (75 mg/kg body weight), the 5th group - with the addition of carnosine and α-lipoic acid in a total dose of 150 mg/kg body weight. The study of rat hepatocyte apoptosis was performed by flow cytometry. Hepatocytes were stained with annexin V and vital dye 7-aminoactinomycin, followed by detection on an flow cytometer. The content of cytokines and chemokines (IL-1α, IL-10, IL-17А, M-CSF, MIP-1α, MIP-3α, RANTES) in the cytoplasmic fraction of liver tissue was determined by multiplex immunoassay. Results and discussion. On the model of the initial stage of development of NAFLD in male Wistar rats the еnrichment of HCCDD with carnosine and α-lipoic acid had demonstrated a protective effect on hepatocytes with a decrease in apoptosis intensity to the level in control rats. Under the influence of HCCDD, an increase in the content of M-CSF and MIP-1α and a decrease in the levels of MIP-3α and RANTES, stimulating the migration and differentiation of various immunoregulatory populations to the parenchyma at an early stage of the formation of fatty hepatosis, in the cytoplasmic fraction of liver tissue were detected. Moreover, a decrease in the level of proinflammatory cytokines IL-17A and IL-1α and an increase in IL-10 produced mainly by Treg-populations indicate the absence of pronounced inflammatory changes in the liver of male Wistar rats at the initial stages of development of fatty dystrophy. Conclusion. Enrichment of HCCDD with both carnosine and α-lipoic acid in Wistar rats had a protective effect on hepatocytes with a decrease in apoptosis to a level in control rats. The increase in the IL-10/IL-17A ratio indicates the activation of anti-inflammatory mechanisms due to the functional predominance of Treg-cells over Th1/Th17 lymphocytes.